| Autor: |
Vetter SW; Institute of Biochemistry, ETH-Zentrum, Zürich, Switzerland. svetter@scripps.edu, Leclerc E |
| Jazyk: |
angličtina |
| Zdroj: |
European journal of biochemistry [Eur J Biochem] 2001 Aug; Vol. 268 (15), pp. 4292-9. |
| DOI: |
10.1046/j.1432-1327.2001.02347.x |
| Abstrakt: |
We have previously characterized the calcium-dependent calmodulin (CaM)-binding domain (Ser76-Ser92) of the 135-kDa human protein 4.1 isoform using fluorescence spectroscopy and chemically synthesized nonphosphorylated or serine phosphorylated peptides [Leclerc, E. & Vetter, S. (1998) Eur. J. Biochem. 258, 567-671]. Here we demonstrate that phosphorylation of two serine residues within the 17-residue peptide alters their ability to adopt alpha helical conformation in a position-dependent manner. The helical content of the peptides was determined by CD-spectroscopy and found to increase from 36 to 45% for the Ser80 phosphorylated peptide and reduce to 28% for the Ser84 phosphorylated peptide; the di-phosphorylated peptide showed 32% helical content. Based on secondary structure prediction methods we propose that initial helix formation involves the central residues Leu82-Phe86. The ability of the peptides to adopt alpha helical conformations did not correlate with the observed binding affinities to CaM. We suggest that the reduced CaM-binding affinities observed for the phosphorylated peptides are more likely to be the result of unfavorable sterical and electrostatic interactions introduced into the CaM peptide-binding interface by the phosphate groups, rather than being due to the effect of phosphorylation on the secondary structure of the peptides. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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