Accession Number : ADA332083

Title :   Antifreeze Polypeptides as Biomineralization Models.

Descriptive Note : Final rept. 15 Aug 94-14 Aug 97,

Corporate Author : TRUSTEES OF BOSTON UNIV MA

Personal Author(s) : Laursen, Richard A.

PDF Url : ADA332083

Report Date : 25 OCT 1997

Pagination or Media Count : 6

Abstract : During the past three years we have focused on three specific aims: (1) understanding the mechanism of ice-binding by antifreeze polypeptides (AFPs), (2) synthesis and characterization of peptides (CBPs) that alter the morphology of a mineral, calcite, and (3) characterizing the interaction between a specific CBP and calcite. In the course of pursuing aim (1), we discovered, in the longhorn sculpin, a new class (type W) of antifreeze protein and have determined completely both its protein and DNA sequences. It contains 108 amino acids and, we believe, based on secondary structure analysis, folds into a 4-helix bundle. We have designed and synthesized an alpha-helical peptide designed 'de novo' to bind to the prism face of calcite. This peptide has a remarkable effect on calcite crystal morphology: at low temperatures, in its helical form, it does appear to bind to a prism face, but when the peptide is unfolded, it causes epitaxial growth off the rhombohedral surfaces of calcite seed crystals, resulting in very unusual morphology. This is perhaps the first example of a rationally designed, morphology controlling mineral binding peptide. We have also synthesized a helical phosphopeptide which appears to bind to the basal face of calcite.

Descriptors :   *PEPTIDES, *MORPHOLOGY, *CALCITE, PROTEINS, EPITAXIAL GROWTH, CRYSTALLIZATION, ANTIFREEZES.

Subject Categories : Biochemistry
      Geology, Geochemistry and Mineralogy
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE