Bacillus licheniformis α-amylase (BLA) was chemically modified using 100-fold molar excess of succinic anhydride over protein or 0.66 M potassium cyanate to obtain 42 % succinylated and 81 % carbamylated BLAs. Size and charge homogeneity of modified preparations was established by Sephacryl S-200 HR gel chromatography and polyacrylamide gel electrophoresis. Conformational alteration in these pr...

The fast and accurate prediction of protein flexibility is one of the major challenges in protein science. Enzyme activity, signal transduction, and ligand binding are dynamic processes involving essential conformational changes ranging from small side chain fluctuations to reorientations of entire domains. In the present work, we describe a reimplementation of the CONCOORD approach, termed tCO...

Human cystatin C (hCC) is a small but very intriguing protein. Produced by all nucleated cells is found in almost all tissues and body fluids where, at physiological conditions, plays a role of a very potent inhibitor of cysteine proteases. Biologically active hCC is a monomeric protein but during cellular trafficking it forms dimers, transiently losing its inhibitory activity. In vitro, dimeri...

A polypeptide chain can adopt many conformations. Yet, the sequence of its amino acid residues directs folding to a particular native state.1 The loss of conformational entropy associated with folding destabilizes the native state. This destabilization is overcome by the hydrophobic effect, hydrogen bonds, other noncovalent interactions, and disulfide bonds.2 We have identified another force th...

The conformational stability and reversibility of unfolding of the human dimeric enzyme Cu Zn superoxide dismutase (HSOD) and the three mutant enzymes constructed by replacement of Cys6 by Ala and Cys111 by Ser, singly and in combination, were determined by differential scanning calorimetry. The differential scanning calorimetry profile of wild-type HSOD consists of two components, which probab...

Bovine pancreatic phospholipase A2 (PLA2), a small (13.8 kDa) Ca2+-dependent lipolytic enzyme, is rich in functional and structural character. In an effort to examine its detailed structure-function relationship, we determined its solution structure by multidimensional nuclear magnetic resonance (NMR) spectroscopy at a functionally relevant pH. An ensemble of 20 structures generated has an aver...

the conformational behavior of monosubstituted tri-methylsilyle ethynyl derivative of cal ix[4]arene as a newgeneration of caliarene was compared with tetra alkylated calyx[4]arene. the most important conformationalphenomena in these compounds which are pinched cone interconversion process were done by semi-empiricalmethod and ab initio calculations with gaussian 98w programming.

The phenomenon of prion strains with distinct biological characteristics has been hypothesized to be involved in the structural diversity of abnormal prion protein (PrP(Sc)). However, the molecular basis of the transmission of strain properties remains poorly understood. Real-time quaking-induced conversion (RT-QUIC) is a cell-free system that uses Escherichia coli-derived recombinant PrP (rPrP...