Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

Chemistry Faculty Publications

Discipline
Institution
Keyword
Publication Year

Articles 91 - 120 of 176

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Identification Of The Domains Of Urer, An Arac-Like Transcriptional Regulator Of The Urease Gene Cluster In Proteus Mirabilis, Carrie A. Poore, Christopher Coker, Jonathan D. Dattelbaum, Harry L.T. Mobley Jan 2001

Identification Of The Domains Of Urer, An Arac-Like Transcriptional Regulator Of The Urease Gene Cluster In Proteus Mirabilis, Carrie A. Poore, Christopher Coker, Jonathan D. Dattelbaum, Harry L.T. Mobley

Chemistry Faculty Publications

Proteus mirabilis urease catalyzes the hydrolysis of urea to CO2 and NH3, resulting in urinary stone formation in individuals with complicated urinary tract infections. UreR, a member of the AraC family, activates transcription of the genes encoding urease enzyme subunits and accessory proteins, ureDABCEFG, as well as its own transcription in the presence of urea. Based on sequence homology with AraC, we hypothesized that UreR contains both a dimerization domain and a DNA-binding domain. A translational fusion of the leucine zipper dimerization domain (amino acids 302 to 350) of C/EBP and the C-terminal half of UreR …

Go to article

Crystal Structure Of Bis(7-Nitro-8-Quinolinolato)Copper(Ii), Cuc18h10o6n4 / M. Shoja, H. Gershon And D. D. Clarke Fordham University, Department Of Chemistry, Fordham Road, Bronx, Ny 10458, Usa, Massud Shoja, Herman Gershon, Donald Dudley Clarke Phd Jan 2000

Crystal Structure Of Bis(7-Nitro-8-Quinolinolato)Copper(Ii), Cuc18h10o6n4 / M. Shoja, H. Gershon And D. D. Clarke Fordham University, Department Of Chemistry, Fordham Road, Bronx, Ny 10458, Usa, Massud Shoja, Herman Gershon, Donald Dudley Clarke Phd

Chemistry Faculty Publications

C1sHwCuN406, monoclinic, P121/cl (No. 14), a= 4.567(9) Å, b = 10.723(8) Å, c = 17.095(6) Å, ~ = 100.0(1)0 , v = 824.5 Å3 , Z = 2, Rgt(F) = 0.043, wRgt(F) = 0.067, T = 293 K

Go to article

Synthesis Of 2-Acetamido-5,6-Dihalophenyl Acetates / Donald D. Clarke, Herman Gershon, And John J. Mcmahon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Donald Dudley Clarke Phd, Herman Gershon, John J. Mcmahon Jan 2000

Synthesis Of 2-Acetamido-5,6-Dihalophenyl Acetates / Donald D. Clarke, Herman Gershon, And John J. Mcmahon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Donald Dudley Clarke Phd, Herman Gershon, John J. Mcmahon

Chemistry Faculty Publications

2-Acetamido-5,6-dihalophenyl acetates were synthesized as intermediates for the preparation of 6, 7-dihalo-8-quinolinols via the Skraup procedure

Go to article

Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella Jan 1999

Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella

Chemistry Faculty Publications

Sodium dodecyl sulfate-polyacrylamide gel analysis of lipooligosaccharide (LOS) from Neisseria meningitidis has demonstrated considerable microheterogeneity in the variable region of LOS due to the presence of novel glycoforms. As a step toward understanding the basis for the expression of these novel glycoforms, we have examined the LOS structures and UDP-glucose 4-epimerase (epimerase) activity levels in two strains (NMB and MA-1) and their respective galE mutants. Strain NMB was found to have low epimerase activity and to contain multiple glycoforms, some of which appear to contain only glucose sugars. The galE mutant had only the oligoglucose glycoforms. Strain MA-1 had higher …

Go to article

Preparation And Fungitoxicity Of Some Dichloro-8-Quinolinols / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1999

Preparation And Fungitoxicity Of Some Dichloro-8-Quinolinols / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

2,5-, 3,5-, 3,7-, 4,5-, 5,6-, und 6,7-Dichloro-8-quinolinols were prepared and tested along with their 3,6- and 5,7-ana1ogues against six fungi (Aspergillus niger, A. oryzae, Myrothecium verrucaria, Trichoderma viride, Mucor cirinelloides, and Trichophyton mentagrophytes) in Sabouraud dextrose broth. Most of the compounds were strongly antifungal, inhibiting five of the fungi below 1 μg/ml. This activity is attributed to intramolecular synergism. M. cirinelloides was inhibited less by these compounds

Go to article

Circulation And Energy Metabolism In The Brain / Donald D. Clarke And Louis Sokoloff, Donald Dudley Clarke Phd, Louis Sokoloff Jan 1999

Circulation And Energy Metabolism In The Brain / Donald D. Clarke And Louis Sokoloff, Donald Dudley Clarke Phd, Louis Sokoloff

Chemistry Faculty Publications

No abstract provided.

Go to article

Two-Photon Excitation Of Rhenium Metal-Ligand Complexes, Joseph R. Lakowicz, Felix N. Castellano, Ignacy Gryczynski, Zygmunt Gryczynski, Jonathan D. Dattelbaum Jan 1999

Two-Photon Excitation Of Rhenium Metal-Ligand Complexes, Joseph R. Lakowicz, Felix N. Castellano, Ignacy Gryczynski, Zygmunt Gryczynski, Jonathan D. Dattelbaum

Chemistry Faculty Publications

We describe the emission spectral properties of two rhenium metal-ligand complexes with one and two-photon excitation, Re(bpy)2(CO)3Cl and [Re(bpy)(CO)3CH3CN]+, where bpy is 2,2’-bipyridyl and CH3CN is acetonitrile. Similar emission spectra and intensity decay times characteristic of the metal-to-ligand charge transfer state were observed for one- and two-photon excitation. The lifetime and quantum yield of the acetonitrile complex are approximately 14-fold higher than that of the chloride complex. Both complexes display high anisotropies near 0.33 in frozen solution with one-photon excitation. Two-photon excitation results in anisotropies about 40% larger, …

Go to article

Phorbol 12-Myristate 13-Acetate Stimulates Lysophosphatidic Acid Secretion From Ovarian And Cervical Cancer Cells But Not From Breast Or Leukemia Cells, Zhongzhou Shen, Jerome Belinson, Richard E. Morton, Yan Xu Dec 1998

Phorbol 12-Myristate 13-Acetate Stimulates Lysophosphatidic Acid Secretion From Ovarian And Cervical Cancer Cells But Not From Breast Or Leukemia Cells, Zhongzhou Shen, Jerome Belinson, Richard E. Morton, Yan Xu

Chemistry Faculty Publications

Lysophosphatidic acid (LPA) is present in ascites from patients with ovarian cancer. It stimulates calcium release and growth of ovarian cancer cells bothin vitroandin vivo.Recently, we found that LPA levels were significantly elevated in plasma from patients with ovarian cancer and other gynecological cancers. In contrast, LPA levels were not elevated in patients with breast cancer and leukemias. In view of this, we investigated whether gynecological cancer cells could produce LPA. LPA was extracted from the supernatant of cells culturedin vitroand purified by thin layer chromatography. After hydrolysis and transmethylation, the fatty acid derivatives were analyzed by gas chromatography. We …

Go to article

Simultaneous Formation Of Functional Leading And Lagging Strand Holoenzyme Complexes On A Small, Defined Dna Substrate, Anthony J. Berdis, Stephen J. Benkovic Sep 1998

Simultaneous Formation Of Functional Leading And Lagging Strand Holoenzyme Complexes On A Small, Defined Dna Substrate, Anthony J. Berdis, Stephen J. Benkovic

Chemistry Faculty Publications

The biochemical characterization of leading and lagging strand DNA synthesis by bacteriophage T4 replication proteins has been addressed utilizing a small, defined primer/template. The ATP hydrolysis activity of 44/62, the clamp loading complex responsible for holoenzyme assembly, was monitored during assembly of both the leading and lagging strand holoenzyme complex. The ATPase activity of 44/62 diminishes once a functional holoenzyme is assembled on both the leading and lagging strand. The assembly of the lagging strand holoenzyme is facilitated by several factors including biotinylated streptavidin blocks at the end of the fork strands, preassembly of the leading strand holoenzyme, and by …

Go to article

Crystal Structures Of Copper(Ii) Complexes Of Some 2-Methyl-8-Quinolinols And Implications For Their Antifungal Activity / Massud Shoja, Herman Gershon, Diana Bray, And Donald D. Clarke Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Massud Shoja Phd, Herman Gershon, Diana Bray, Donald Dudley Clarke Phd Jan 1998

Crystal Structures Of Copper(Ii) Complexes Of Some 2-Methyl-8-Quinolinols And Implications For Their Antifungal Activity / Massud Shoja, Herman Gershon, Diana Bray, And Donald D. Clarke Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Massud Shoja Phd, Herman Gershon, Diana Bray, Donald Dudley Clarke Phd

Chemistry Faculty Publications

A hypothesis that the geometry of a potential fungicide must be consistent with that of the pores of the fungal spore wall in order to penetrate it and be toxic has been developed. Certain bis(8-quinolinolato)copper(II) complexes seemed to contradict this. To resolve this issue, structures of bis(7-fluoro-8-quinolinolato )copper(II) (1), bis(2-methyl-8-quinolinolato )copper(II) (2), and bis(2-methyl-7-nitro-8-quinolinolato)copper(II) (3) were solved. The ligands of 1 are square planar with copper at the center of symmetry. In 2 and 3 the methyl group at C2 interacts with the other 8- quinolinol ligand, producing a significant distortion of the square planar geometry which causes a rotation …

Go to article

Revision Of The Assigned Structures Of 5- And 7-Iodo-8-Quinolinols And 5- And 7-Iodo-2-Methyl-8-Quinolinols / Donald D. Clarke, Herman Gershon, Massud Shoja, And Mei-Wen Yen Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Donald Dudley Clarke Phd, Herman Gershon, Massud Shoja Phd, Mei-Wen Yen Jan 1998

Revision Of The Assigned Structures Of 5- And 7-Iodo-8-Quinolinols And 5- And 7-Iodo-2-Methyl-8-Quinolinols / Donald D. Clarke, Herman Gershon, Massud Shoja, And Mei-Wen Yen Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Donald Dudley Clarke Phd, Herman Gershon, Massud Shoja Phd, Mei-Wen Yen

Chemistry Faculty Publications

Revised structures are presented for 5- and 7-iodo-8-quinolinols and for 5- and 7-iodo-2-methyl-8-quinolinols based on NMR studies. UV spectroscopic characterization of the compounds was also carried out

Go to article

Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella Jan 1997

Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella

Chemistry Faculty Publications

Haemophilus influenzae is an important human pathogen. The lipooligosaccharide (LOS) of H. influenzae has been implicated as a virulence determinant. To better understand the assembly of LOS in nontypeable H. influenzae (NtHi), we have cloned and characterized the rfaD and rfaF genes of NtHi 2019, which encode the ADP-L-glycero-D-manno-heptose-6-epimerase and heptosyltransferase II enzymes, respectively. This cloning was accomplished by the complementation of Salmonella typhimurium lipopolysaccharide (LPS) biosynthesis gene mutants. These deep rough mutants are novobiocin susceptible until complemented with the appropriate gene. In this manner, we are able to use novobiocin resistance to select for specific NtHi LOS inner core …

Go to article

Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson Jan 1997

Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson

Chemistry Faculty Publications

To define the role of the surface lipooligosaccharide (LOS) of Haemophilus ducreyi in the pathogenesis of chancroid, Tn916 mutants of H. ducreyi 35000 defective in expression of the murine monoclonal antibody (MAb) 3F11 epitope on H. ducreyi LOS were identified by immunologic screening. One mutant, designated 1381, has an LOS which lacks the MAb 3F11 epitope and migrates with an increased mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gene disrupted by the Tn916 element in strain 1381 was identified by cloning the sequences flanking the Tn916 element. The sequences were then used to probe a lambda DASHII genomic library. …

Go to article

Nerve Tissue-Specific Human Glutamate Dehydrogenase That Is Thermolabile And Highly Regulated By Adp / P. Shashidharan, Donald D. Clarke, Naveed Ahmed, Nicholas Moschonas, And Andreas Plaitakis Department Of Neurology, Mount Sinai School Of Medicine, New York; Department Of Chemistry, Fordham University, Bronx New York, Usa; And Department Of Biology And School Of Health Sciences, University Of Crete, Crete, Greece, P. Shashidharan, Donald Dudley Clarke Phd, Naveed Ahmed, Nicholas Moschonas Jan 1997

Nerve Tissue-Specific Human Glutamate Dehydrogenase That Is Thermolabile And Highly Regulated By Adp / P. Shashidharan, Donald D. Clarke, Naveed Ahmed, Nicholas Moschonas, And Andreas Plaitakis Department Of Neurology, Mount Sinai School Of Medicine, New York; Department Of Chemistry, Fordham University, Bronx New York, Usa; And Department Of Biology And School Of Health Sciences, University Of Crete, Crete, Greece, P. Shashidharan, Donald Dudley Clarke Phd, Naveed Ahmed, Nicholas Moschonas

Chemistry Faculty Publications

Glutamate dehydrogenase (GDH), an enzyme that is central to the metabolism of glutamate, is present at high levels in the mammalian brain. Studies on human leukocytes and rat brain suggested the presence of two GDH activities differing in thermal stability and allosteric regulation, but molecular biological investigations led to the cloning of two human GDH-specific genes encoding highly homologous polypeptides. The first gene, designated GLUD1, is expressed in all tissues (housekeeping GDH), whereas the second gene, designated GLUD2, is expressed specifically in neural and testicular tissues. In this study, we obtained both GDH isoenzymes in pure form by expressing a …

Go to article

Protein-Protein And Protein-Dna Interactions At The Bacteriophage T4 Dna Replication Fork. Characterization Of A Fluorescently Labeled Dna Polymerase Sliding Clamp, Daniel J. Sexton, Theodore E. Carver, Anthony J. Berdis, Stephen J. Benkovic Nov 1996

Protein-Protein And Protein-Dna Interactions At The Bacteriophage T4 Dna Replication Fork. Characterization Of A Fluorescently Labeled Dna Polymerase Sliding Clamp, Daniel J. Sexton, Theodore E. Carver, Anthony J. Berdis, Stephen J. Benkovic

Chemistry Faculty Publications

The T4 DNA polymerase holoenzyme is composed of the polymerase enzyme complexed to the sliding clamp (the 45 protein), which is loaded onto DNA by an ATP-dependent clamp loader (the 44/62 complex). This paper describes a new method to directly investigate the mechanism of holoenzyme assembly using a fluorescently labeled cysteine mutant of the 45 protein. This protein possessed unaltered function yet produced substantial changes in probe fluorescence intensity upon interacting with other components of the holoenzyme. These fluorescence changes provide insight into the role of ATP hydrolysis in holoenzyme assembly. Using either ATP or the non-hydrolyzable ATP analog, adenosine …

Go to article

The Carboxyl Terminus Of The Bacteriophage T4 Dna Polymerase Is Required For Holoenzyme Complex Formation, Anthony J. Berdis, Patrice Soumillion, Stephen J. Benkovic Nov 1996

The Carboxyl Terminus Of The Bacteriophage T4 Dna Polymerase Is Required For Holoenzyme Complex Formation, Anthony J. Berdis, Patrice Soumillion, Stephen J. Benkovic

Chemistry Faculty Publications

To further elucidate the mechanism and dynamics of bacteriophage T4 holoenzyme formation, a mutant polymerase in which the last six carboxyl-terminal amino acids are deleted, was constructed, overexpressed, and purified to homogeneity. The mutant polymerase, designated ΔC6 exo−, is identical to wild-type exo− polymerase with respect to kcat, kpol, and dissociation constants for nucleotide and DNA substrate. However, unlike wild-type exo− polymerase, the ΔC6 exo− polymerase is unable to interact with the 45 protein to form the stable holoenzyme. A synthetic polypeptide corresponding to the carboxyl terminus of the wild-type exo− polymerase was tested as an in vitro inhibitor of …

Go to article

The Lipooligosaccharides Of Haemophilus Ducreyi Are Highly Sialylated, William Melaugh, A A. Campagnari, B W. Gibson Jan 1996

The Lipooligosaccharides Of Haemophilus Ducreyi Are Highly Sialylated, William Melaugh, A A. Campagnari, B W. Gibson

Chemistry Faculty Publications

The major lipooligosaccharides of the sexually transmitted pathogen Haemophilus ducreyi 35000 have been previously found to terminate in N-acetyllactosamine and sialyl-N-acetyllactosamine, Neu5Ac alpha 2-->3Gal beta 1-->4GlcNAc (W. Melaugh, N. J. Phillips, A. A. Campagnari, M. V. Tullius, and B. W. Gibson, Biochemistry 33: 13070-13078, 1994). In this study, mass spectrometry and composition analyses have shown that the lipooligosaccharides from three other H. ducreyi strains also contain N-acetyllactosamine and are highly sialylated (approximately 30 to 50%), although one African strain was found to contain neither of these structural features.

Go to article

Preparation And Fungitoxicity Of 3-Bromo-6-Chloro- And 6-Bromo-3-Chloro-8-Quinolinols / Gershon H., Clarke D. D., Gerhson M, Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1996

Preparation And Fungitoxicity Of 3-Bromo-6-Chloro- And 6-Bromo-3-Chloro-8-Quinolinols / Gershon H., Clarke D. D., Gerhson M, Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

3-Bromo-6-chloro- and 6-bromo-3-chloro-8-nitro, -8-amino-, and -8-hydroxyquinolines along with 3-bromo- and 3-chloroquinolin-6,8-diols were prepared and tested for antifungal activity against six fungi (Aspergillus niger, A. oryzae, Myrothecium verrucaria, Trichoderma viride, Mucor cirinelloides, Trichophyton mentagrophytes) in Sabouraud dextrose broth. Compounds with chlorine in the 3 position were generally more fungitoxic than the corresponding analogues with bromine. 6-Bromo-3-chloro-8-quinolinol inhibited four fungi at levels below 1 μg/ml and A. niger and M. cirinelloides at 2 μg/ml each

Go to article

Antifungal Activity Of Halophenols And Halonitrophenols / H. Gershon, D. D. Clarke, And M. Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1995

Antifungal Activity Of Halophenols And Halonitrophenols / H. Gershon, D. D. Clarke, And M. Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

Thirty one compounds (phenol; its 12 possible monohalo analogues; 18 nitrophenols (2- and 4-nitrophenols, 4-, 5-, and 6-halo-2-nitrophenols, 3-halo-4-nitrophenols)) were tested for antifungal activity against six fungi (A. niger, A. oryzae, M. verrucaria, T. viride, M. cirinelloides, and T. mentagrophytes) in Sabouraud dextrose broth. The two most fungitoxic compounds of those studied were 5-fluoro- and 5-iodo-2-nitrophenols which inhibited all the fungi at concentrations under 10 μg/ml. 6-Iodo-2-nitrophenol inhibited five fungi at a concentration below 10 μg/ml and M. cirinelloides at 10- 100 μg/ ml

Go to article

Substituted 8-Quinolinols: Halo, Nitro, And Sulfonic Acids / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, New York 10458 U.S.A., New York Botanical Garden, Bronx, New York 10458, U.S.A., Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1995

Substituted 8-Quinolinols: Halo, Nitro, And Sulfonic Acids / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, New York 10458 U.S.A., New York Botanical Garden, Bronx, New York 10458, U.S.A., Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

Methods have been systematized for preparing substituted 8-quinolinols. The 5 and 7 positions are those available for electrophilic substitution. The entry position of the electrophile can be controlled by controlling the prototropic form of the 8-quinolinol. Under acidic conditions the 5 position is attacked first and under basic conditions the electrophile is directed to the 7 position. Iodination is the reverse. Regiospecificity also can be achieved by blocking the 5 or 7 position with sulfonic acid groups followed by addition of the electrophile and deblocking by acid hydrolysis, providing the new substituent is stable to acid hydrolysis. When compounds containing …

Go to article

Dissection Of An Antibody-Catalyzed Reaction, Jon D. Stewart, Joseph F. Krebs, Gary Siuzdak, Anthony J. Berdis, David B. Smithrud, Stephen J. Benkovic Aug 1994

Dissection Of An Antibody-Catalyzed Reaction, Jon D. Stewart, Joseph F. Krebs, Gary Siuzdak, Anthony J. Berdis, David B. Smithrud, Stephen J. Benkovic

Chemistry Faculty Publications

Antibody 43C9 accelerates the hydrolysis of a p-nitroanilide by a factor of 2.5 x 10(5) over the background rate in addition to catalyzing the hydrolysis of a series of aromatic esters. Since this represents one of the largest rate accelerations achieved with an antibody, we have undertaken a series of studies aimed at uncovering the catalytic mechanism of 43C9. The immunogen, a phosphonamidate, was designed to mimic the geometric and electronic characteristics of the tetrahedral intermediate that forms upon nucleophilic attack by hydroxide on the amide substrate. Further studies, however, revealed that the catalytic mechanism is more complex and involves …

Go to article

Use Of Pyocin To Select A Haemophilus Ducreyi Variant Defective In Lipooligosaccharide Biosynthesis, A A. Campagnari, R Karalus, M A. Apicella, William Melaugh, A J. Lesse, B W. Gibson Jan 1994

Use Of Pyocin To Select A Haemophilus Ducreyi Variant Defective In Lipooligosaccharide Biosynthesis, A A. Campagnari, R Karalus, M A. Apicella, William Melaugh, A J. Lesse, B W. Gibson

Chemistry Faculty Publications

Haemophilus ducreyi, a cause of genital ulcer disease in developing countries, appears to facilitate the heterosexual transmission of the human immunodeficiency virus in Africa. Despite an increase in studies of this gram-negative human pathogen, little is known about the pathogenesis of chancroid. Our studies have shown that the lipooligosaccharides (LOS) of H. ducreyi may play an important role in ulcer formation. Monoclonal antibody and mass spectrometric analyses identified a terminal trisaccharide present on H. ducreyi LOS that is immunochemically similar to human paragloboside. This epitope is present on the LOS of Neisseria gonorrhoeae, and it may be the site of …

Go to article

Evidence Of Steric Factors In The Fungitoxic Mechanism Of 8-Quinolinol And Its 2-, 3-, 4-, 5-, 6- And 7-Chloro And Bromo Analogues / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1994

Evidence Of Steric Factors In The Fungitoxic Mechanism Of 8-Quinolinol And Its 2-, 3-, 4-, 5-, 6- And 7-Chloro And Bromo Analogues / Herman Gershon, Donald D. Clarke, And Muriel Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

A study was made of the fungitoxicity of 2-, 3-, 4-, 5-, 6- and 7-chloro and bromo- 8-quinolinols against Aspergillus niger, A. oryzae, Myrothecium verrucaria, Trichoderma viride and Trichophyton mentagrophytes in Sabouraud dextrose broth and in Yeast Nitrogen Base supplemented with 1% D-glucose and 0.088% L-asparagine. Based on the presence or absence of synergism between pairs of substituted 8-quinolinols and reversal or nonreversal of toxicity by L-cysteine or Nacetyl- L-cysteine, the following conclusions were reached: (1) substituents on the quinoline ring change the site(s) of action of the toxicant; (2) the sites of action of the 5-, 6-, and 7-chloro-8-quinolinols …

Go to article

Preparation And Fungitoxicity Of 3,6-Dichloro- And 3,6-Dibromo-8-Quinolinols / H. Gershon, D. D. Clarke, And M. Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1994

Preparation And Fungitoxicity Of 3,6-Dichloro- And 3,6-Dibromo-8-Quinolinols / H. Gershon, D. D. Clarke, And M. Gershon Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

3,6-Dichloro- and 3,6-dibromo-8-quinolinols were prepared by direct halogenation of 8-nitroquinoline by N-halosuccinimide in acetic acid or by halogenation of the corresponding 6-halo-8-nitroquinoline prepared via a Skraup reaction. The nitro group was reduced to amino and the amine was hydrolyzed to the phenol in 70% sulfuric acid at 220 °C. The fungitoxicity of 3,6-dichloro- and 3,6-dibromo-8-quinolinols, as well as intermediates in their preparation, against Aspergillus niger, Aspergillus oryzae, Myrothecium verrucaria, Trichoderma viride, and Mucor cirinelloides was determined. 3,6-dichloro-8-quinolinol is the most fungitoxic analogue of this class of compounds observed to date

Go to article

The 2′-Phosphate Of Nadp Is Critical For Optimum Productive Binding To 6-Phosphogluconate Dehydrogenase From Candida Utilis, Anthony J. Berdis, Paul F. Cook Sep 1993

The 2′-Phosphate Of Nadp Is Critical For Optimum Productive Binding To 6-Phosphogluconate Dehydrogenase From Candida Utilis, Anthony J. Berdis, Paul F. Cook

Chemistry Faculty Publications

Initial velocity studies obtained with alternative dinucleotide substrates for the 6-phosphogluconate dehydrogenase reaction suggest that the 2′-phosphate is critical for the optimum productive binding of the dinucleotide substrate. Initial velocity patterns obtained by varying 6-phosphogluconate at different fixed levels of NAD are nearly parallel with apparent competitive substrate inhibition by 6-phosphogluconate at pH 7 and below but intersect to the left of the ordinate at pH 8 and above. Dead-end inhibition studies indicate that the mechanism is random at all pH values. Data are interpreted in terms of a random mechanism with marked antagonism in the binding of NAD and …

Go to article

Investigation Of The Structural Heterogeneity Of Lipooligosaccharides From Pathogenic Haemophilus And Neisseria Species And Of R-Type Lipopolysaccharides From Salmonella Typhimurium By Electrospray Mass Spectrometry, B W. Gibson, William Melaugh, Nancy J. Phillips, M A. Apicella, A A. Campagnari, J M. Griffiss Jan 1993

Investigation Of The Structural Heterogeneity Of Lipooligosaccharides From Pathogenic Haemophilus And Neisseria Species And Of R-Type Lipopolysaccharides From Salmonella Typhimurium By Electrospray Mass Spectrometry, B W. Gibson, William Melaugh, Nancy J. Phillips, M A. Apicella, A A. Campagnari, J M. Griffiss

Chemistry Faculty Publications

Heterogeneity in the lipooligosaccharides (LOS) of pathogenic Haemophilus and Neisseria species is evident from the multiplicity of components observed with electrophoretic analyses. Knowledge of the precise structures that make up these diverse LOS molecules is clearly the key to reaching an understanding of pathogenic processes such as phase variation and molecular mimicry. Except for a few cases, little is known about the specific structural features of LOS that underlie phase variation and molecular mimicry, partly because of the inherent difficulties in the structural elucidation of these complex glycolipids. In the lipopolysaccharides (LPS) from Salmonella typhimurium and Escherichia coli, rough, or …

Go to article

Reexamination Of The Thermolytic Rearrangement Of 4-Halophenyl Azides To 2-Aminophenols And Other Products / H. Gershon, D. D. Clarke, And M. Gershon, Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1993

Reexamination Of The Thermolytic Rearrangement Of 4-Halophenyl Azides To 2-Aminophenols And Other Products / H. Gershon, D. D. Clarke, And M. Gershon, Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, New York Botanical Garden, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

The halogenation of derivatives of 2-aminophenol with N-chloro- and N-bromosuccinimides at ambient temperatures in acetic acid was studied. With the necessary compounds available, a reexamination of the thermolytic rearrangement of 2-halophenyl azides to 2-aminophenols and other products was undertaken. It is certain that the rearrangement of 4-halophenyl azides to 2-aminophenols occurs but the products identified in this study differ significantly from those reported previously by Suschitzky et al. (1963, 1966)

Go to article

Improved Syntheses Of Some Monochloro- And Monobromo-8-Quinolinols / Herman Gershon And Donald D. Clarke Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd Jan 1991

Improved Syntheses Of Some Monochloro- And Monobromo-8-Quinolinols / Herman Gershon And Donald D. Clarke Department Of Chemistry, Fordham University, Bronx, Ny 10458, Usa, Herman Gershon, Donald Dudley Clarke Phd

Chemistry Faculty Publications

Procedures were developed for the preparation of the 2-, 3-, 4-, and 6-monosubstituted chloro and bromo 8-quinolinols which afforded greater yields and/or reduced the number of steps in the preparation. 100 MHz 1H-NMR spectra for the 12 possible monochloro and mono bromo analogues are given

Go to article

Fluoroacetate And Fluorocitrate: Mechanism Of Action / Donald D. Clarke, Donald Dudley Clarke Phd Jan 1991

Fluoroacetate And Fluorocitrate: Mechanism Of Action / Donald D. Clarke, Donald Dudley Clarke Phd

Chemistry Faculty Publications

The concept of lethal synthesis as suggested by Peters is reviewed in the light of the more recent work in this area. It is suggested that fluorocitrate is a "suicide" substrate for aconitase rather than a competitive inhibitor as originally suggested. The use of these substances to study glialneuronal relationships is considered

Go to article

Evidence Of Steric Factors In The Fungitoxic Mechanism Of 8-Quinolinol And Its 5- And 7-Halogenated Analogues / Herman Gershon, Donald D. Clarke, And Muriel Gershon, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon Jan 1991

Evidence Of Steric Factors In The Fungitoxic Mechanism Of 8-Quinolinol And Its 5- And 7-Halogenated Analogues / Herman Gershon, Donald D. Clarke, And Muriel Gershon, Herman Gershon, Donald Dudley Clarke Phd, Muriel Gershon

Chemistry Faculty Publications

Antifungal studies were made of mixtures of minimal inhibitory concentrations (MICs) of 8-quinolinol and its 5- and 7-halo analogues against six fungi: Aspergillus niger, A. oryzae, Trichoderma viride, Myrothecium verrucaria, Mucor cirinelloides, and Trichophyton mentagrophytes. Mixtures of 8-quinolinol with 5- or 7-fluoro-8-quinolinol and of 5- and 7-fluoro-8-quinolinol showed additive activity, and their respective toxicities were reversed by L-cysteine. These results suggested a common mechanism of activity for the three toxicants. Potentiation of the fungitoxicity of mixtures of 8-quinolinol and its 5- and 7-chloro, bromo, and iodo analogues, as well as mixtures of 5- and 7-chloro, 5- and 7-bromo, and 5- …

Go to article

First Prev Next Last