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Articles 1 - 7 of 7
Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Expression, Purification, And Characterization Of Thymidylate Synthase From Lactococcus Lactis, Patricia Greene, Pak-Lam Yu, Jia Zhao, Celia Schiffer, Daniel Santi
Expression, Purification, And Characterization Of Thymidylate Synthase From Lactococcus Lactis, Patricia Greene, Pak-Lam Yu, Jia Zhao, Celia Schiffer, Daniel Santi
Celia A. Schiffer
The thymidylate synthase (TS) gene from Lactococcus lactis has been highly expressed in Escherichia coli. The TS protein was purified by sequential chromatography on Q-Sepharose and phenyl-Sepharose. Six grams of cell pellet yielded 140 mg of homogeneous TS. TS is a highly conserved enzyme, and several of the conserved amino acid residues that have been implicated in catalytic function are altered in L. lactis TS. By use of a 3-dimensional homology model, we have predicted covariant changes that might compensate for these differences. With the large amounts of L. lactis TS now available, studies can be pursued to understand the …
Discovery Of Hiv-1 Protease Inhibitors With Picomolar Affinities Incorporating N-Aryl-Oxazolidinone-5-Carboxamides As Novel P2 Ligands, Akbar Ali, G. S. Kiran Kumar Reddy, Hong Cao, Saima Anjum, Madhavi Nalam, Celia Schiffer, Tariq Rana
Discovery Of Hiv-1 Protease Inhibitors With Picomolar Affinities Incorporating N-Aryl-Oxazolidinone-5-Carboxamides As Novel P2 Ligands, Akbar Ali, G. S. Kiran Kumar Reddy, Hong Cao, Saima Anjum, Madhavi Nalam, Celia Schiffer, Tariq Rana
Celia A. Schiffer
Here, we describe the design, synthesis, and biological evaluation of novel HIV-1 protease inhibitors incorporating N-phenyloxazolidinone-5-carboxamides into the (hydroxyethylamino)sulfonamide scaffold as P2 ligands. Series of inhibitors with variations at the P2 phenyloxazolidinone and the P2' phenylsulfonamide moieties were synthesized. Compounds with the (S)-enantiomer of substituted phenyloxazolidinones at P2 show highly potent inhibitory activities against HIV-1 protease. The inhibitors possessing 3-acetyl, 4-acetyl, and 3-trifluoromethyl groups at the phenyl ring of the oxazolidinone fragment are the most potent in each series, with K(i) values in the low picomolar (pM) range. The electron-donating groups 4-methoxy and 1,3-dioxolane are preferred at P2' phenyl ring, …
Substrate Shape Determines Specificity Of Recognition For Hiv-1 Protease: Analysis Of Crystal Structures Of Six Substrate Complexes, Moses Prabu-Jeyabalan, Ellen Nalivaika, Celia Schiffer
Substrate Shape Determines Specificity Of Recognition For Hiv-1 Protease: Analysis Of Crystal Structures Of Six Substrate Complexes, Moses Prabu-Jeyabalan, Ellen Nalivaika, Celia Schiffer
Celia A. Schiffer
The homodimeric HIV-1 protease is the target of some of the most effective antiviral AIDS therapy, as it facilitates viral maturation by cleaving ten asymmetric and nonhomologous sequences in the Gag and Pol polyproteins. Since the specificity of this enzyme is not easily determined from the sequences of these cleavage sites alone, we solved the crystal structures of complexes of an inactive variant (D25N) of HIV-1 protease with six peptides that correspond to the natural substrate cleavage sites. When the protease binds to its substrate and buries nearly 1000 A2 of surface area, the symmetry of the protease is broken, …
Accounting For Molecular Mobility In Structure Determination Based On Nuclear Magnetic Resonance Spectroscopic And X-Ray Diffraction Data, Wilfred Van Gunsteren, Roger Brunne, P. Gros, René Van Schaik, Celia Schiffer, Andrew Torda
Accounting For Molecular Mobility In Structure Determination Based On Nuclear Magnetic Resonance Spectroscopic And X-Ray Diffraction Data, Wilfred Van Gunsteren, Roger Brunne, P. Gros, René Van Schaik, Celia Schiffer, Andrew Torda
Celia A. Schiffer
No abstract provided.
Design And Synthesis Of Hiv-1 Protease Inhibitors Incorporating Oxazolidinones As P2/P2' Ligands In Pseudosymmetric Dipeptide Isosteres, G. S. Kiran Kumar Reddy, Akbar Ali, Madhavi Nalam, Saima Anjum, Hong Cao, Robin Nathans, Celia Schiffer, Tariq Rana
Design And Synthesis Of Hiv-1 Protease Inhibitors Incorporating Oxazolidinones As P2/P2' Ligands In Pseudosymmetric Dipeptide Isosteres, G. S. Kiran Kumar Reddy, Akbar Ali, Madhavi Nalam, Saima Anjum, Hong Cao, Robin Nathans, Celia Schiffer, Tariq Rana
Celia A. Schiffer
A series of novel HIV-1 protease inhibitors based on two pseudosymmetric dipeptide isosteres have been synthesized and evaluated. The inhibitors were designed by incorporating N-phenyloxazolidinone-5-carboxamides into the hydroxyethylene and (hydroxyethyl)hydrazine dipeptide isosteres as P2 and P2' ligands. Compounds with (S)-phenyloxazolidinones attached at a position proximal to the central hydroxyl group showed low nM inhibitory activities against wild-type HIV-1 protease. Selected compounds were further evaluated for their inhibitory activities against a panel of multidrug-resistant protease variants and for their antiviral potencies in MT-4 cells. The crystal structures of lopinavir (LPV) and two new inhibitors containing phenyloxazolidinone-based ligands in complex with wild-type …
Structure-Based Design, Synthesis, And Structure-Activity Relationship Studies Of Hiv-1 Protease Inhibitors Incorporating Phenyloxazolidinones, Akbar Ali, G. S. Kiran Kumar Reddy, Madhavi Nalam, Saima Anjum, Hong Cao, Celia Schiffer, Tariq Rana
Structure-Based Design, Synthesis, And Structure-Activity Relationship Studies Of Hiv-1 Protease Inhibitors Incorporating Phenyloxazolidinones, Akbar Ali, G. S. Kiran Kumar Reddy, Madhavi Nalam, Saima Anjum, Hong Cao, Celia Schiffer, Tariq Rana
Celia A. Schiffer
A series of new HIV-1 protease inhibitors with the hydroxyethylamine core and different phenyloxazolidinone P2 ligands were designed and synthesized. Variation of phenyl substitutions at the P2 and P2' moieties significantly affected the binding affinity and antiviral potency of the inhibitors. In general, compounds with 2- and 4-substituted phenyloxazolidinones at P2 exhibited lower binding affinities than 3-substituted analogues. Crystal structure analyses of ligand-enzyme complexes revealed different binding modes for 2- and 3-substituted P2 moieties in the protease S2 binding pocket, which may explain their different binding affinities. Several compounds with 3-substituted P2 moieties demonstrated picomolar binding affinity and low nanomolar …
Accessibility And Order Of Water Sites In And Around Proteins: A Crystallographic Time-Averaging Study, Celia Schiffer, Wilfred Van Gunsteren
Accessibility And Order Of Water Sites In And Around Proteins: A Crystallographic Time-Averaging Study, Celia Schiffer, Wilfred Van Gunsteren
Celia A. Schiffer
Water plays an essential role in most biological processes. Water molecules solvating biomolecules are generally in fast exchange with the environment. Nevertheless, well-defined electron density is seen for water associated with proteins whose crystal structure is determined to high resolution. The relative accessibility of these water sites is likely to be relevant to their biological role but is difficult to assess. A time-averaging crystallographic refinement simulation on basic pancreatic trypsin inhibitor successfully characterizes the relative accessibility of the crystallographic water sites. In such a refinement simulation water diffuses through the crystal lattice in a manner that is consistent with the …