| Title: | Environmentally induced reversible conformational switching in the yeast cell adhesion protein alpha-agglutinin |
| Author(s): | Zhao H; Chen MH; Shen ZM; Kahn PC; Lipke PN; |
| Address: | "Department of Biological Sciences and the Institute for Biomolecular Structure and Function, Hunter College of the City University of New York, New York 10021,USA" |
| ISSN/ISBN: | 0961-8368 (Print) 1469-896X (Electronic) 0961-8368 (Linking) |
| Abstract: | "The yeast cell adhesion protein alpha-agglutinin is expressed on the surface of a free-living organism and is subjected to a variety of environmental conditions. Circular dichroism (CD) spectroscopy shows that the binding region of alpha-agglutinin has a beta-sheet-rich structure, with only approximately 2% alpha-helix under native conditions (15-40 degrees C at pH 5.5). This region is predicted to fold into three immunoglobulin-like domains, and models are consistent with the CD spectra as well as with peptide mapping and site-specific mutagenesis. However, secondary structure prediction algorithms show that segments comprising approximately 17% of the residues have high alpha-helical and low beta-sheet potential. Two model peptides of such segments had helical tendencies, and one of these peptides showed pH-dependent conformational switching. Similarly, CD spectroscopy of the binding region of alpha-agglutinin showed reversible conversion from beta-rich to mixed alpha/beta structure at elevated temperatures or when the pH was changed. The reversibility of these changes implied that there is a small energy difference between the all-beta and the alpha/beta states. Similar changes followed cleavage of peptide or disulfide bonds. Together, these observations imply that short sequences of high helical propensity are constrained to a beta-rich state by covalent and local charge interactions under native conditions, but form helices under non-native conditions" |
| Keywords: | "Algorithms Amino Acid Sequence Cell Adhesion Circular Dichroism Disulfides Environment Hydrogen-Ion Concentration Immunoglobulins/chemistry Mating Factor Models, Molecular Molecular Sequence Data Mutagenesis, Site-Directed Peptide Mapping Peptides/*chemis;" |
| Notes: | "MedlineZhao, H Chen, M H Shen, Z M Kahn, P C Lipke, P N eng G12 RR003037/RR/NCRR NIH HHS/ 1R01-GM47176/GM/NIGMS NIH HHS/ RR-03037/RR/NCRR NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 2001/05/23 Protein Sci. 2001 Jun; 10(6):1113-23. doi: 10.1110/ps.41701" |
