SUNY at Albany
June 19-23, 2001
Protein structure and folding, a new start
In a globular protein the polypeptide chain returns to itself many times, making numerous chain-to-chain contacts - closed loops. This simple view of the protein structure, inexplicable, has never been considered. A statistical analysis of the sizes and locations of the closed loops in all major protein folds revealed that the loops have an almost-standard contour lengths of 25-30 amino acid residues and follow one after another along the chain . The loop closure is maintained primarily by van der Waals interactions. A specific way to identify the tightest contacts of prime importance for the stability of a given crystallized protein is suggested and the notion of the van der Waals locks is introduced . The loops closed by the van der Waals interactions provide a principally novel view of protein globule organization: the loop-n-lock structure. This opens a new perspective in understanding protein folding as well: the consecutive looping of the polypeptide chain and the locking of the loop ends by tight van der Waals interactions.
References and Footnotes
Igor N. Berezovsky* and Edward N. Trifonov
Department of Structural Biology, The Weizmann Institute of Science, P.O.B. 26,
Rehovot 76100, Israel