temporary banners

 



 

Journal Issue - Volume 10 Issue 5 (May 2001)

Abstract Carbonic anhydrases fall into three distinct evolutionary and structural classes: α, β, and γ. The β‐class carbonic anhydrases (β‐CAs) are widely distributed among higher plants, simple eukaryotes, eubacteria, and archaea. We have determined the crystal structure of ECCA, a β‐CA from Escherichia coli, to a resolution of 2.0 Å. In agreement with the structure of the β‐CA from the chloroplast of the red alga Porphyridium purpureum, the...

Abstract A new class of matrix metalloproteinase (MMP) inhibitors has been identified by screening a collection of compounds against stromelysin. The inhibitors, 2,4,6‐pyrimidine triones, have proven to be potent inhibitors of gelatinases A and B. An X‐ray crystal structure of one representative compound bound to the catalytic domain of stromelysin shows that the compounds bind at the active site and ligand the active‐site zinc. The...

Abstract The structure of calbindin D9k with two substitutions was determined by X‐ray crystallography at 1.8‐Å resolution. Unlike wild‐type calbindin D9k, which is a monomeric protein with two EF‐hands, the structure of the mutated calbindin D9k reveals an intertwined dimer. In the dimer, two EF‐hands of the monomers have exchanged places, and thus a 3D domain‐swapped dimer has been formed. EF‐hand I of molecule A is packed toward EF‐hand II of molecule B...

Abstract The endoprotease furin, which belongs to the family of mammalian proprotein convertase (PC), is synthesized as a zymogen with an N‐terminal, 81‐residue inhibitory prodomain. It has been shown that the proenzyme form of furin undergoes a multistep ‘autocatalytic’ removal of the prodomain at the C‐terminal side of the two consensus sites, R78‐T‐K‐R81∼ and R44‐G‐V‐T‐K‐R49∼. The furin‐mediated cleavage at R44‐G‐V‐T‐K‐R49∼, in particular,...

Abstract Helix formation of an S‐peptide analog, comprising the first 20 residues of Ribonuclease A and two additional N‐terminal residues, was studied by measuring hydrogen bond (H‐bond) h3JNC′ scalar couplings as a function of 2,2,2‐trifluoroethanol (TFE) concentration. The h3JNC′ couplings give direct evidence for the closing of individual backbone N‐H•••O = C H‐bonds during the TFE‐induced formation of secondary structure. Whereas no h3JNC′...

Abstract The crystal structure of human deoxy hemoglobin (Hb) complexed with a potent allosteric effector (2‐[4‐[[(3,5‐dimethylanilino)carbonyl]methyl]phenoxy]‐2‐methylpropionic acid) = RSR‐13) is reported at 1.85 Å resolution. Analysis of the hemoglobin:effector complex indicates that two of these molecules bind to the central water cavity of deoxy Hb in a symmetrical fashion, and that each constrains the protein by engaging in...

Abstract DF1 is a small, idealized model for carboxylate‐bridged diiron proteins. This protein was designed to form a dimeric four‐helix bundle with a dimetal ion‐binding site near the center of the structure, and its crystal structure has confirmed that it adopts the intended conformation. However, the protein showed limited solubility in aqueous buffer, and access to its active site was blocked by two hydrophobic side chains. The...

Abstract The thermal denaturation of ribonuclease A (RNase A) in the presence of phosphate at neutral pH was studied by differential scanning calorimetry (DSC) and a combination of optical spectroscopic techniques to probe the existence of intermediate states. Fourier transform infrared (FTIR) spectra of the amide I′ band and far‐uv circular dichroism (CD) spectra were used to monitor changes in the secondary structure. Changes in...

Abstract The family of three‐dimensional molecular structures of the major coat protein from the M13 bacteriophage, which was determined in detergent micelles by NMR methods, has been analyzed by constrained geometry optimization in a phospholipid environment. A single‐layer solvation shell of dioleoyl phosphatidylcholine lipids was built around the protein, after replacing single residues by cysteines with a covalently attached...

Abstract The crystal structures of a deletion mutant of human thymidylate synthase (TS) and its ternary complex with dUMP and Tomudex have been determined at 2.0 Å and 2.5 Å resolution, respectively. The mutant TS, which lacks 23 residues near the amino terminus, is as active as the wild‐type enzyme. The ternary complex is observed in the open conformation, similar to that of the free enzyme and to that of the ternary complex of rat...

Abstract The mouse major urinary proteins are pheromone‐binding proteins that function as carriers of volatile effectors of mouse physiology and behavior. Crystal structures of recombinant mouse major urinary protein‐I (MUP‐I) complexed with the synthetic pheromones, 2‐sec‐butyl‐4,5‐dihydrothiazole and 6‐hydroxy‐6‐methyl‐3‐heptanone, have been determined at high resolution. The purification of MUP‐I from mouse liver and a...

Abstract A function annotation method using the sequence‐to‐structure‐to‐function paradigm is applied to the identification of all disulfide oxidoreductases in the Saccharomyces cerevisiae genome. The method identifies 27 sequences as potential disulfide oxidoreductases. All previously known thioredoxins, glutaredoxins, and disulfide isomerases are correctly identified. Three of the 27 predictions are probable false‐positives. Three novel...

Abstract The structure and function of hydroxynitrile lyase from Manihot esculenta (MeHNL) have been analyzed by X‐ray crystallography and site‐directed mutagenesis. The crystal structure of the MeHNL–S80A mutant enzyme has been refined to an R‐factor of 18.0% against diffraction data to 2.1‐Å resolution. The three‐dimensional structure of the MeHNL–S80A–acetone cyanohydrin complex was determined at 2.2‐Å resolution and refined to an R‐factor...

Abstract Patterns of hydrophobic and hydrophilic residues play a major role in protein folding and function. Long, predominantly hydrophobic strings of 20–22 amino acids each are associated with transmembrane helices and have been used to identify such sequences. Much less attention has been paid to hydrophobic sequences within globular proteins. In prior work on computer simulations of the competition between on‐pathway folding and...

Abstract An amino acid sequence, in the context of the solvent environment, contains all of the thermodynamic information necessary to encode a three‐dimensional protein structure. To investigate the relationship between an amino acid sequence and its corresponding protein fold, a database of thermodynamic stability information was assembled that spanned 2951 residues from 44 nonhomologous proteins. This information was obtained...

Page:   1 2 Next