SOLVENT ACCESSIBILITY ANALYSIS ON THE MUTANTS OF HSC70 ATPASE FRAGMENT

Molecular chaperones are the cellular proteins which mediate the corre ct folding of other polypeptides. The concept of 'solvent accessibilit y' is one of the most powerful tools to understand the structure and s tability of protein molecules. The hydrophobic variation of amino acid residues due to point mutations at many active sites of chaperone pro tein Hsc70 using solvent accessibility analysis is carried out. The nu merical indices for several properties of amino acid residues, such as , reduction in accessibility, preference of amino acid residues in int erior and surface parts, transfer free energy and the preference of am ino acid residues to change their positions (buried/exposed) due to am ino acid substitutions for Hsc70 and its mutants were set up. The acce ssibility of amino acid residues varies much between native and mutant proteins whereas there is no major changes on their conformations. Th e conformational stability for Hsc70 and its mutants were established and the computed hydrophobic free energy change is around 10 kcal/mol due to single amino acid substitution. (C) 1998 Elsevier Science B.V. All rights reserved.