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Full-Text Articles in Life Sciences

Strong Dna Deformation Required For Extremely Slow Dna Threading Intercalation By A Binuclear Ruthenium Complex, Ali A. Almaqwashi, Thayaparan Paramanathan, Per Lincoln, Ioulia Rouzina, Fredrik Westerlund, Mark C. Williams Jan 2014

Strong Dna Deformation Required For Extremely Slow Dna Threading Intercalation By A Binuclear Ruthenium Complex, Ali A. Almaqwashi, Thayaparan Paramanathan, Per Lincoln, Ioulia Rouzina, Fredrik Westerlund, Mark C. Williams

Physics Faculty Publications

DNA intercalation by threading is expected to yield high affinity and slow dissociation, properties desirable for DNA-targeted therapeutics. To measure these properties, we utilize single molecule DNA stretching to quantify both the binding affinity and the force-dependent threading intercalation kinetics of the binuclear ruthenium complex Δ,Δ-[μ‐bidppz‐(phen)4Ru2]4+ (Δ,Δ-P). We measure the DNA elongation at a range of constant stretching forces using optical tweezers, allowing direct characterization of the intercalation kinetics as well as the amount intercalated at equilibrium. Higher forces exponentially facilitate the intercalative binding, leading to a profound decrease in the binding site size that …


Structure Of The Catalytic Chain Of Methanococcus Jannaschii Aspartate Transcarbamoylase In A Hexagonal Crystal Form: Insights Into The Path Of Carbamoyl Phosphate To The Active Site Of The Enzyme, Jacqueline Vitali, Aditya K. Singh, Alexei S. Soaresb, Michael J. Colaneri May 2012

Structure Of The Catalytic Chain Of Methanococcus Jannaschii Aspartate Transcarbamoylase In A Hexagonal Crystal Form: Insights Into The Path Of Carbamoyl Phosphate To The Active Site Of The Enzyme, Jacqueline Vitali, Aditya K. Singh, Alexei S. Soaresb, Michael J. Colaneri

Physics Faculty Publications

Crystals of the catalytic chain of Methanococcus jannaschii aspartate transcarbamoylase (ATCase) grew in the presence of the regulatory chain in the hexagonal space group P6322, with one monomer per asymmetric unit. This is the first time that crystals with only one monomer in the asymmetric unit have been obtained; all known structures of the catalytic subunit contain several crystallographically independent monomers. The symmetry-related chains form the staggered dimer of trimers observed in the other known structures of the catalytic subunit. The central channel of the catalytic subunit contains a sulfate ion and a K+ ion as …


Crystallization And Structure Determination Of The Catalytic Trimer Of Methanococcus Jannaschii Aspartate Transcarbamoylase, Jacqueline Vitali, Tatyana Vorobyova, Gordon Websterb, Evan R. Kantrowitza Aug 2000

Crystallization And Structure Determination Of The Catalytic Trimer Of Methanococcus Jannaschii Aspartate Transcarbamoylase, Jacqueline Vitali, Tatyana Vorobyova, Gordon Websterb, Evan R. Kantrowitza

Physics Faculty Publications

Aspartate transcarbamoylase (ATCase) catalyzes the first step in the pyrimidine biosynthetic pathway, the reaction between carbamoyl phosphate and L-aspartate to form N-carbamoyl-L-aspartate and phosphate. The structural analysis of the ATCase catalytic trimer from Methanococcus jannaschii, a unicellular thermophilic archaeabacterium, has been undertaken in order to gain insight into the structural features that are responsible for the thermostability of the enzyme. As a first step, the catalytic trimer was crystallized in space group R32, with unit-cell parameters a = b = 265.3, c = 195.5 Å and two trimers in the asymmetric unit. Its structure was determined using …


Three-Dimensional Structure Of The Gly121tyr Dimeric Form Of Ornithine Decarboxylase From Lactobacillus 30a, Jacqueline Vitali, Donald Carroll, Rochika G. Chaudhrya, Marvin L. Hackert Dec 1999

Three-Dimensional Structure Of The Gly121tyr Dimeric Form Of Ornithine Decarboxylase From Lactobacillus 30a, Jacqueline Vitali, Donald Carroll, Rochika G. Chaudhrya, Marvin L. Hackert

Physics Faculty Publications

Ornithine decarboxylases catalyze the conversion of ornithine to putrescine at the beginning of the polyamine pathway. Ornithine decarboxylase (ODC) from Lactobacillus 30a is a 990612 Da dodecamer composed of six homodimers. A single point mutation (Gly121Tyr) was found to prevent association of dimers into dodecamers. The dimeric protein has been crystallized at pH 7.0 in the presence of guanosine triphosphate (GTP). Crystals belong to space group P3221, with unit-cell parameters a = 111.8, c = 135.9 Å and one monomer in the asymmetric unit. The structure was determined by molecular replacement and refined using simulated annealing to …


Sequence Profile Of The Parallel Β Helix In The Pectate Lyase Superfamily, Susan Heffron, Gregory R. Moe, Volker Sieber, Jerome Mengaud, Pascale Cossart, Jacqueline Vitali, Frances Jumak Jan 1998

Sequence Profile Of The Parallel Β Helix In The Pectate Lyase Superfamily, Susan Heffron, Gregory R. Moe, Volker Sieber, Jerome Mengaud, Pascale Cossart, Jacqueline Vitali, Frances Jumak

Physics Faculty Publications

The parallel β helix structure found in the pectatelyasesuperfamily has been analyzed in detail. A comparative analysis of known structures has revealed a unique sequenceprofile, with a strong positional preference for specific amino acids oriented toward the interior of the parallel β helix. Using the unique sequenceprofile, search patterns have been constructed and applied to the sequence databases to identify a subset of proteins that are likely to fold into the parallel β helix. Of the 19 families identified, 39% are known to be carbohydrate-binding proteins, and 50% belong to a broad category of proteins with sequences containing leucine-rich repeats …


The Three-Dimensional Structure Of Aspergillus Niger Pectin Lyase B At 1.7-Å Resolution1, Jacqueline Vitali, Brian Schick, Harry C.M. Kester, Jaap Visser, Frances Jurnak Jan 1998

The Three-Dimensional Structure Of Aspergillus Niger Pectin Lyase B At 1.7-Å Resolution1, Jacqueline Vitali, Brian Schick, Harry C.M. Kester, Jaap Visser, Frances Jurnak

Physics Faculty Publications

The three-dimensional structure of Aspergillus niger pectin lyase B (PLB) has been determined by crystallographic techniques at a resolution of 1.7 Å. The model, with all 359 amino acids and 339 water molecules, refines to a final crystallographic R factor of 16.5%. The polypeptide backbone folds into a large right-handed cylinder, termed a parallel b helix. Loops of various sizes and conformations protrude from the central helix and probably confer function. The largest loop of 53 residues folds into a small domain consisting of three antiparallel b strands, one turn of an a helix, and one turn of a 310 …


Structure Of A Bovine Thrombin-Hirudin51-65 Complex Determined By A Combination Of Molecular Replacement And Graphics. Incorporation Of Known Structural Information In Molecular Replacement, Jacqueline Vitali, Philip D. Martin, Michael G. Malkowski, Cris M. Olsen, Paul H. Johnson, Brian F.P. Edwards May 1996

Structure Of A Bovine Thrombin-Hirudin51-65 Complex Determined By A Combination Of Molecular Replacement And Graphics. Incorporation Of Known Structural Information In Molecular Replacement, Jacqueline Vitali, Philip D. Martin, Michael G. Malkowski, Cris M. Olsen, Paul H. Johnson, Brian F.P. Edwards

Physics Faculty Publications

Crystals of the bovine thrombin-hirudins51-65 complex have space group P6122 with cell constants a = 116.4, and c = 200.6 Å and two thrombin molecules in the asymmetric unit. Only one thrombin molecule could be located by generalized molecular replacement; the second was fit visually as a rigid body to an improved electron-density difference map. The structure was refined to R = 0.192 with two B values per residue (main chain and side chain) at 3.2 Å. The polar interactions of the peptides with the exosite of thrombin show differences consistent with the known flexibility in …


Crystallization Of Hemoglobins Ii And Iii Of The Symbiont-Harboring Clam Lucina Pectinata, M. A. Doyle, Jacqueline Vitali, J. B. Wittenberg, S. N. Vinogradov, D. A. Walz, B. F.P. Edwards, P. D. Martin Sep 1994

Crystallization Of Hemoglobins Ii And Iii Of The Symbiont-Harboring Clam Lucina Pectinata, M. A. Doyle, Jacqueline Vitali, J. B. Wittenberg, S. N. Vinogradov, D. A. Walz, B. F.P. Edwards, P. D. Martin

Physics Faculty Publications

Diffraction data to 2.7 A resolution were measured on crystals of the homotetramers of components II and III of the cytoplacmic hemoglobin of the symbiont-harboring clam Lucina pectinata. Even though the crystallization conditions are different and the sequence homology of the two hemoglobins is only 63%, the crystals are isomorphous to each other and to the heterotetramer Hb II/III, implying that the residues primarily involved in the intermolecular interactions and responsible for crystal cohesion may be invariant.


The Structure Of A Complex Of Bovine &-Thrombin And Recombinant Hirudin At 2.8-A Resolution, Jacqueline Vitali, Philip D. Martin, Michael G. Malkowski, William D. Robertson, Jerome B. Lazar, Richard C. Winant, Paul H. Johnson, Brian F.P. Edwards Sep 1992

The Structure Of A Complex Of Bovine &-Thrombin And Recombinant Hirudin At 2.8-A Resolution, Jacqueline Vitali, Philip D. Martin, Michael G. Malkowski, William D. Robertson, Jerome B. Lazar, Richard C. Winant, Paul H. Johnson, Brian F.P. Edwards

Physics Faculty Publications

Crystals of the complex of bovine alpha-thrombin with recombinant hirudin variant 1 have space group C222(1) with cell constants a = 59.11, b = 102.62, and c = 143.26 A. The orientation and position of the thrombin component was determined by molecular replacement and the hirudin molecule was fit in 2 magnitude of Fo - magnitude of Fc electron density maps. The structure was refined by restrained least squares and simulated annealing to R = 0.161 at 2.8-A resolution. The binding of hirudin to thrombin is generally similar to that observed in the crystals of human thrombin-hirudin. Several differences in …


Using Xenon As A Heavy Atom For Determining Phases In Sperm Whale Metmyoglobin, Jacqueline Vitali, Arthur H. Robbins, Steven C. Almo, Robert F. Tilton Oct 1991

Using Xenon As A Heavy Atom For Determining Phases In Sperm Whale Metmyoglobin, Jacqueline Vitali, Arthur H. Robbins, Steven C. Almo, Robert F. Tilton

Physics Faculty Publications

Xenon gas can be used as a heavy atom for determining phases in a protein. We demonstrate that an interpretable electron density map can be obtained for sperm whale metmyoglobin from a single xenon derivative using iterative single isomorphous replacement with the anomalous scattering method.