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Full-Text Articles in Physical Sciences and Mathematics

Distinct Conformational Behaviors Of Four Mammalian Dual-Flavin Reductases (Cytochrome P450 Reductase, Methionine Synthase Reductase, Neuronal Nitric Oxide Synthase, Endothelial Nitric Oxide Synthase) Determine Their Unique Catalytic Profiles, Mohammad Mahfuzul Haque, Mekki Bayachou, Jesus Tejero, Claire T. Kenney, Naw M. Pearl, Sang-Choul Im, Lucy Waskell, Dennis J. Stuehr Dec 2014

Distinct Conformational Behaviors Of Four Mammalian Dual-Flavin Reductases (Cytochrome P450 Reductase, Methionine Synthase Reductase, Neuronal Nitric Oxide Synthase, Endothelial Nitric Oxide Synthase) Determine Their Unique Catalytic Profiles, Mohammad Mahfuzul Haque, Mekki Bayachou, Jesus Tejero, Claire T. Kenney, Naw M. Pearl, Sang-Choul Im, Lucy Waskell, Dennis J. Stuehr

Chemistry Faculty Publications

Multidomain enzymes often rely on large conformational motions to function. However, the conformational setpoints, rates of domain motions and relationships between these parameters and catalytic activity are not well understood. To address this, we determined and compared the conformational setpoints and the rates of conformational switching between closed unreactive and open reactive states in four mammalian diflavin NADPH oxidoreductases that catalyze important biological electron transfer reactions: cytochrome P450 reductase, methionine synthase reductase and endothelial and neuronal nitric oxide synthase. We used stopped-flow spectroscopy, single turnover methods and a kinetic model that relates electron flux through each enzyme to its conformational …


Rnase L Contributes To Experimentally Induced Type 1 Diabetes Onset In Mice, Chun Zeng, Xin Yi, Danny Zipris, Hongli Liu, Lin Zhang, Qiaoyun Zheng, Krishnamurthy Malathi, Ge Jin, Aimin Zhou Dec 2014

Rnase L Contributes To Experimentally Induced Type 1 Diabetes Onset In Mice, Chun Zeng, Xin Yi, Danny Zipris, Hongli Liu, Lin Zhang, Qiaoyun Zheng, Krishnamurthy Malathi, Ge Jin, Aimin Zhou

Chemistry Faculty Publications

The cause of type 1 diabetes continues to be a focus of investigation. Studies have revealed that interferon α (IFNα) in pancreatic islets after viral infection or treatment with double-stranded RNA (dsRNA), a mimic of viral infection, is associated with the onset of type 1 diabetes. However, how IFNα contributes to the onset of type 1 diabetes is obscure. In this study, we found that 2-5A-dependent RNase L (RNase L), an IFNα-inducible enzyme that functions in the antiviral and antiproliferative activities of IFN, played an important role in dsRNA-induced onset of type 1 diabetes. Using RNase L-deficient, rat insulin promoter-B7.1 …


Rnase L Interacts With Filamin A To Regulate Actin Dynamics And Barrier Function For Viral Entry, Krishnamurthy Malathi, Mohammad Adnan Siddiqui, Shubham Dayal, Merna Naji, Heather J, Ezelle, Chun Zeng, Aimin Zhou, Bret A. Hassel Nov 2014

Rnase L Interacts With Filamin A To Regulate Actin Dynamics And Barrier Function For Viral Entry, Krishnamurthy Malathi, Mohammad Adnan Siddiqui, Shubham Dayal, Merna Naji, Heather J, Ezelle, Chun Zeng, Aimin Zhou, Bret A. Hassel

Chemistry Faculty Publications

The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells …


Cryoprotective Effect Of L-Carnitine On Motility, Vitality And Dna Oxidation Of Human Spermatozoa, S. Banihani, A. Agarwal, R. Sharma, Mekki Bayachou Aug 2014

Cryoprotective Effect Of L-Carnitine On Motility, Vitality And Dna Oxidation Of Human Spermatozoa, S. Banihani, A. Agarwal, R. Sharma, Mekki Bayachou

Chemistry Faculty Publications

Successful cryopreservation for human spermatozoa markedly influences the reproductive outcomes of assisted reproductive technologies. But in spite of its usefulness, cryopreservation significantly decreases sperm quality. l-carnitine has been found to improve the quality of spermatozoa in selected cases with male infertility. Here, we examined the efficacy of l-carnitine in improving sperm motility and vitality and reducing sperm DNA oxidation during cryopreservation. Semen samples from infertile patients (n = 22) were collected and analysed. Cryopreservation medium supplemented with l-carnitine was mixed with the semen at a ratio of 1 : 1 (v/v). The final l-carnitine concentration in each cryovial was 0.5 …


Metabolomics Of Apcmin/+ Mice Genetically Susceptible To Intestinal Cancer, Jean Eudes J. Dazard, Yana Sandlers, Stephanie K. Doerner, Nathan A. Berger, Henri Brunengraber Jun 2014

Metabolomics Of Apcmin/+ Mice Genetically Susceptible To Intestinal Cancer, Jean Eudes J. Dazard, Yana Sandlers, Stephanie K. Doerner, Nathan A. Berger, Henri Brunengraber

Chemistry Faculty Publications

Background: To determine how diets high in saturated fat could increase polyp formation in the mouse model of intestinal neoplasia, ApcMin/+, we conducted large-scale metabolome analysis and association study of colon and small intestine polyp formation from plasma and liver samples of ApcMin/+ vs. wild-type littermates, kept on low vs. high-fat diet. Label-free mass spectrometry was used to quantify untargeted plasma and acyl-CoA liver compounds, respectively. Differences in contrasts of interest were analyzed statistically by unsupervised and supervised modeling approaches, namely Principal Component Analysis and Linear Model of analysis of variance. Correlation between plasma metabolite concentrations and polyp numbers was …


A New Liquid Chromatography/Tandem Mass Spectrometry Method For Quantification Of Gangliosides In Human Plasma, Qianyang Huang, Xiang Zhou, Danting Liu, Baozhong Xin, Karen Cechner, Heng Wang, Aimin Zhou Jun 2014

A New Liquid Chromatography/Tandem Mass Spectrometry Method For Quantification Of Gangliosides In Human Plasma, Qianyang Huang, Xiang Zhou, Danting Liu, Baozhong Xin, Karen Cechner, Heng Wang, Aimin Zhou

Chemistry Faculty Publications

Gangliosides are a family of glycosphingolipids characterized by mono- or polysialic acid-containing oligosaccharides linked through 1,3- and 1,4-β glycosidic bonds with subtle differences in structure that are abundantly present in the central nervous systems of many living organisms. Their cellular surface expression and physiological malfunction are believed to be pathologically implicated in considerable neurological disorders, including Alzheimer and Parkinson diseases. Recently, studies have tentatively elucidated that mental retardation or physical stagnation deteriorates as the physiological profile of gangliosides becomes progressively and distinctively abnormal during the development of these typical neurodegenerative syndromes. In this work, a reverse-phase liquid chromatography/tandem mass spectrometry …


Lead Optimization Of Dual Tubulin And Hsp27 Inhibitors, Bo Zhong, Rati Lama, Daniel G. Kulman, Bibo Li Ph.D., Bin Su Ph.D. Jun 2014

Lead Optimization Of Dual Tubulin And Hsp27 Inhibitors, Bo Zhong, Rati Lama, Daniel G. Kulman, Bibo Li Ph.D., Bin Su Ph.D.

Chemistry Faculty Publications

Tubulin and heat shock protein 27 (Hsp27) are well-characterized molecular targets for anti-cancer drug development. We previously identified lead compounds that inhibited both Hsp27 and tubulin. These compounds exhibited extensive anti-cancer activities against the proliferation of various human cancer cell lines. In the current study, a systematic ligand based structural optimization led to new analogs that significantly inhibited the growth of a panel of breast cancer cell lines. Furthermore, the most potent compounds were examined with tubulin polymerization assay and Hsp27 chaperone activity assay. The compounds showed potent tubulin polymerization inhibition but no Hsp27 inhibitory effect. The structural optimization dissected …


Development And Validation Of Lc–Ms/Ms Method For Quantitative Determination Of (−)-Securinine In Mouse Plasma, Simuli L. Wabuyele, David Wald, Yan Xu Jun 2014

Development And Validation Of Lc–Ms/Ms Method For Quantitative Determination Of (−)-Securinine In Mouse Plasma, Simuli L. Wabuyele, David Wald, Yan Xu

Chemistry Faculty Publications

(−)-Securinine (SE) is a major alkaloid found in plant Securinega suffruticosa, which has a wide range of pharmacological activities including anticancer, anti-parasitic and central nervous system stimulating effects, etc. To aid the pharmacological study of SE, we developed an LC–MS/MS method for quantitative determination of SE in mouse plasma. In this method, plasma samples were first prepared with salting-out assisted liquid–liquid extraction using cold acetonitrile (−20 °C) and 2.00 M ammonium acetate. Separation of SE and the internal standard (IS) from sample matrix was achieved on a Gemini Nx C18 column using 40% acetonitrile and 60% 10.0 mM ammonium acetate …


Reclaiming The Efficacy Of Β-Lactam–Β-Lactamase Inhibitor Combinations: Avibactam Restores The Susceptibility Of Cmy-2-Producing Escherichia Coli To Ceftazidime, Krisztina M. Papp-Wallace, Marisa L. Winkler, Julian A. Gatta, Magdalena A. Taracila, Sujatha Chilakala, Yan Xu, J. Kristie Johnson, Robert A. Bonomo May 2014

Reclaiming The Efficacy Of Β-Lactam–Β-Lactamase Inhibitor Combinations: Avibactam Restores The Susceptibility Of Cmy-2-Producing Escherichia Coli To Ceftazidime, Krisztina M. Papp-Wallace, Marisa L. Winkler, Julian A. Gatta, Magdalena A. Taracila, Sujatha Chilakala, Yan Xu, J. Kristie Johnson, Robert A. Bonomo

Chemistry Faculty Publications

CMY-2 is a plasmid-encoded Ambler class C cephalosporinase that is widely disseminated in Enterobacteriaceae and is responsible for expanded-spectrum cephalosporin resistance. As a result of resistance to both ceftazidime and β-lactamase inhibitors in strains carrying blaCMY, novel β-lactam–β-lactamase inhibitor combinations are sought to combat this significant threat to β-lactam therapy. Avibactam is a bridged diazabicyclo [3.2.1]octanone non-β-lactam β-lactamase inhibitor in clinical development that reversibly inactivates serine β-lactamases. To define the spectrum of activity of ceftazidime-avibactam, we tested the susceptibilities of Escherichia coli clinical isolates that carry blaCMY-2 or blaCMY-69 and investigated the inactivation kinetics of CMY-2. Our analysis showed that …


Site-Specific Nitration Of Apolipoprotein A-I At Tyrosine 166 Is Both Abundant Within Human Atherosclerotic Plaque And Dysfunctional, Joseph A. Didonato, Kulwant Aulak, Ying Huang, Matthew A. Wagner, Gary Gerstenecker, Celalettin Topbas, Valentin Gogonea, Anthony J. Didonato, W.H. Wilson Tang, Ryan A. Mehl, Paul L. Fox, Edward F. Plow, Jonathan D. Smith, Edward A. Fisher, Stanley L. Hazen Apr 2014

Site-Specific Nitration Of Apolipoprotein A-I At Tyrosine 166 Is Both Abundant Within Human Atherosclerotic Plaque And Dysfunctional, Joseph A. Didonato, Kulwant Aulak, Ying Huang, Matthew A. Wagner, Gary Gerstenecker, Celalettin Topbas, Valentin Gogonea, Anthony J. Didonato, W.H. Wilson Tang, Ryan A. Mehl, Paul L. Fox, Edward F. Plow, Jonathan D. Smith, Edward A. Fisher, Stanley L. Hazen

Chemistry Faculty Publications

We reported previously that apolipoprotein A-I (apoA-I) is oxidatively modified in the artery wall at tyrosine 166 (Tyr166), serving as a preferred site for post-translational modification through nitration. Recent studies, however, question the extent and functional importance of apoA-I Tyr166 nitration based upon studies of HDL-like particles recovered from atherosclerotic lesions. We developed a monoclonal antibody (mAb 4G11.2) that recognizes, in both free and HDL-bound forms, apoA-I harboring a 3-nitrotyrosine at position 166 apoA-I (NO2-Tyr166-apoA-I) to investigate the presence, distribution, and function of this modified apoA-I form in atherosclerotic and normal artery wall. We also developed recombinant apoA-I with site-specific …


Lead Optimization Of Hmba To Develop Potent Hexim1 Inducers, Bo Zhong, Rati Lama, Wannarasmi Ketchart, Monica M. Montano, Bin Su Mar 2014

Lead Optimization Of Hmba To Develop Potent Hexim1 Inducers, Bo Zhong, Rati Lama, Wannarasmi Ketchart, Monica M. Montano, Bin Su

Chemistry Faculty Publications

The potency of a series of Hexamethylene bis-acetamide (HMBA) derivatives inducing Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) was determined in LNCaP prostate cancer cells. Several compounds with unsymmetrical structures showed significantly improved activity. Distinct from HMBA, these analogs have increased hydrophobicity and can improve the short half-life of HMBA, which is one of the factors that have limited the application of HMBA in clinics. The unsymmetrical scaffolds of the new analogs provide the basis for further lead optimization of the compounds using combinatorial chemistry strategy.


An Abundant Dysfunctional Apolipoprotein A1 In Human Atheroma, Ying Huang, Joseph A. Didonato, Bruce S. Levison, Dave Schmitt, Lin Li, Yuping Wu, Jennifer Buffa, Timothy Kim, Gary S. Gerstenecker, Xiaodong Gu, Chandra S. Kadiyala, Zeneng Wang, Miranda K. Culley, Jennie E. Hazen, Anthony J. Didonato, Xiaoming Fu, Stela Z. Berisha, Daoquan Peng, Truc T. Nguyen, Shaohong Liang, Chia-Chi Chuang, Leslie Cho, Edward F. Plow, Paul L. Fox, Valentin Gogonea, W.H. Wilson Tang, John S. Parks, Edward A. Fisher, Jonathan D. Smith, Stanley L. Hazen Feb 2014

An Abundant Dysfunctional Apolipoprotein A1 In Human Atheroma, Ying Huang, Joseph A. Didonato, Bruce S. Levison, Dave Schmitt, Lin Li, Yuping Wu, Jennifer Buffa, Timothy Kim, Gary S. Gerstenecker, Xiaodong Gu, Chandra S. Kadiyala, Zeneng Wang, Miranda K. Culley, Jennie E. Hazen, Anthony J. Didonato, Xiaoming Fu, Stela Z. Berisha, Daoquan Peng, Truc T. Nguyen, Shaohong Liang, Chia-Chi Chuang, Leslie Cho, Edward F. Plow, Paul L. Fox, Valentin Gogonea, W.H. Wilson Tang, John S. Parks, Edward A. Fisher, Jonathan D. Smith, Stanley L. Hazen

Chemistry Faculty Publications

Recent studies have indicated that high-density lipoproteins (HDLs) and their major structural protein, apolipoprotein A1 (apoA1), recovered from human atheroma are dysfunctional and are extensively oxidized by myeloperoxidase (MPO). In vitro oxidation of either apoA1 or HDL particles by MPO impairs their cholesterol acceptor function. Here, using phage display affinity maturation, we developed a high-affinity monoclonal antibody that specifically recognizes both apoA1 and HDL that have been modified by the MPO-H2O2-Cl− system. An oxindolyl alanine (2-OH-Trp) moiety at Trp72 of apoA1 is the immunogenic epitope. Mutagenesis studies confirmed a critical role for apoA1 Trp72 in MPO-mediated inhibition of the ATP-binding …


Bsa–Boronic Acid Conjugate As Lectin Mimetics, Satya Nandana Narla, Poornima Pinnamaneni, Huan Nie, Yu Li, Xue-Long Sun Jan 2014

Bsa–Boronic Acid Conjugate As Lectin Mimetics, Satya Nandana Narla, Poornima Pinnamaneni, Huan Nie, Yu Li, Xue-Long Sun

Chemistry Faculty Publications

We report bovine serum albumin (BSA)–boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA–BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS–PAGE gel. The BSA–BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA–BA conjugates was conducted by immobilizing BSA–BA onto SPR gold chip. Overall, we demonstrated a BSA–BA-based …


Quantification Of Free Sialic Acid In Human Plasma Through A Robust Quinoxalinone Derivatization And Lc–Ms/Ms Using Isotope-Labeled Standard Calibration, Dan Wang, Xiang Zhou, Lin Wang, Sihe Wang, Xue-Long Sun Jan 2014

Quantification Of Free Sialic Acid In Human Plasma Through A Robust Quinoxalinone Derivatization And Lc–Ms/Ms Using Isotope-Labeled Standard Calibration, Dan Wang, Xiang Zhou, Lin Wang, Sihe Wang, Xue-Long Sun

Chemistry Faculty Publications

We report an accurate quantification of free sialic acid (SA) in human plasma using LC–MS/MS method with isotope-labeled standard calibration (ILSC) and robust derivatization. Specifically, derivatization of SA with a stable and inexpensive 3,4-diaminotoluene (DAT) provides a stable product of SA with high MS response, proving a convenient and cost-effective LC–MS/MS analysis of free SA. In addition, the use of 13C3-SA as calibration standard ensured the accuracy for the measurement. This assay used ultra high performance liquid chromatography (UHPLC) for separation of native/labeled SA and IS from matrix interference, and employed mass spectrometry in multiple reaction monitoring …


Glyco-Modification Of Protein With O-Cyanate Chain-End Functionalized Glycopolymer Via Isourea Bond Formation, Valentinas Gruzdys, Hailong Zhang, Xue-Long Sun Jan 2014

Glyco-Modification Of Protein With O-Cyanate Chain-End Functionalized Glycopolymer Via Isourea Bond Formation, Valentinas Gruzdys, Hailong Zhang, Xue-Long Sun

Chemistry Faculty Publications

Glycoengineering aimed at addition of carbohydrates to proteins is an attractive approach to alter pharmacokinetic properties of proteins such as enhancing stability and prolonging the duration of action. We report a novel protein glyco-modification of BSA and recombinant thrombomodulin with O-cyanate chain-end functionalized glycopolymer via isourea bond formation. The protein glycoconjugates were confirmed by SDS-PAGE, western blot, and MALDI-TOF Mass Spectrometry. Protein C activation activity of the glyco-modified recombinant thrombomodulin was confirmed, proving no interference to activity from the glycopolymer modification. The isourea bond formation under mild conditions was demonstrated as an alternative method for protein modification with polymers.


Synthesis And Evaluation Of Some New Aza-B-Homocholestane Derivatives As Anticancer Agents, Yanmin Huang, Jianguo Cui, Sijing Chen, Qifu Lin, Huacan Song, Chunfang Gan, Bin Su, Aimin Zhou Jan 2014

Synthesis And Evaluation Of Some New Aza-B-Homocholestane Derivatives As Anticancer Agents, Yanmin Huang, Jianguo Cui, Sijing Chen, Qifu Lin, Huacan Song, Chunfang Gan, Bin Su, Aimin Zhou

Chemistry Faculty Publications

Using analogues of some marine steroidal oximes as precursors, a series of aza-B-homocholestane derivatives possessing different substituted groups at the 3-position of the steroidal nucleus were synthesized. Their biological activity against cancer cell proliferation was determined with multiple cancer cell lines. Aza-B-homocholestane derivatives possessing 3-hydroxyl, 3-hydroximino and 3-thiosemicarbazone groups displayed remarkable cytotoxicity to cancer cells via apoptosis inducing mechanism. Compounds 5, 10, 12, 15 and 18 exhibited better potency to inhibit cancer cell proliferation. In addition, compound 15 was further evaluated with three dimensional (3D) multicellular spheroids assay to determine its potency against spheroid growth. The structure-activity relationship (SAR) generated …


Metabolomic Analysis Of Liver Tissue From The Vx2 Rabbit Model Of Secondary Liver Tumors, R. Ibarra, J. E. Dazard, Y. Sandlers, F. Rehman, R. Abbas, R. Kombu, G. F. Zhang, H. Brunengraber, J. Sanabria Jan 2014

Metabolomic Analysis Of Liver Tissue From The Vx2 Rabbit Model Of Secondary Liver Tumors, R. Ibarra, J. E. Dazard, Y. Sandlers, F. Rehman, R. Abbas, R. Kombu, G. F. Zhang, H. Brunengraber, J. Sanabria

Chemistry Faculty Publications

Purpose. The incidence of liver neoplasms is rising in USA. The purpose of this study was to determine metabolic profiles of liver tissue during early cancer development. Methods. We used the rabbit VX2 model of liver tumors (LT) and a control group consisting of sham animals implanted with Gelfoam into their livers (LG). After two weeks from implantation, liver tissue from lobes with and without tumor was obtained from experimental animals (LT+/LT-) as well as liver tissue from controls (LG+/LG-). Peaks obtained by Gas Chromatography-Mass Spectrometry were subjected to identification. 56 metabolites were identified and their profiles compared between groups …


A Kinetic Analysis Of The Inhibition Of Fox-4 Β-Lactamase, A Plasmid-Mediated Ampc Cephalosporinase, By Monocyclic Β-Lactams And Carbapenems, Krisztina M. Papp-Wallace, Susana Mallo, Christopher R. Bethel, Magdalena A. Taracila, Andrea M. Hujer, Ana Fernandez, Julian A. Gatta, Kerri M. Smith, Yan Xu, Malcolm G.P. Page, Eric Desarbre, German Bou, Robert A. Bonomo Jan 2014

A Kinetic Analysis Of The Inhibition Of Fox-4 Β-Lactamase, A Plasmid-Mediated Ampc Cephalosporinase, By Monocyclic Β-Lactams And Carbapenems, Krisztina M. Papp-Wallace, Susana Mallo, Christopher R. Bethel, Magdalena A. Taracila, Andrea M. Hujer, Ana Fernandez, Julian A. Gatta, Kerri M. Smith, Yan Xu, Malcolm G.P. Page, Eric Desarbre, German Bou, Robert A. Bonomo

Chemistry Faculty Publications

Abstract: Objectives: Class C β-lactamases are prevalent among Enterobacteriaceae; however, these enzymes are resistant to inactivation by commercially available β-lactamase inhibitors. In order to find novel scaffolds to inhibit class C β-lactamases, the comparative efficacy of monocyclic β-lactam antibiotics (aztreonam and the siderophore monosulfactam BAL30072), the bridged monobactam β-lactamase inhibitor BAL29880, and carbapenems (imipenem, meropenem, doripenem and ertapenem) were tested in kinetic assays against FOX-4, a plasmid-mediated class C β-lactamase (pmAmpC). Methods: The FOX-4 β-lactamase was purified. Steady-state kinetics, electrospray ionization mass spectrometry (ESI-MS) and ultraviolet difference (UVD) spectroscopy were conducted using the β-lactam scaffolds described. Results: The Ki values …