$B!J(B15$B!K(BEnergy landscape of a peptide, cut from a distal $B&B(B-hairpin of SH3 domain, including random-coil,$B&B(B-hairpin, and $B&A(B-helix, and pathways among the conformations
Kazuyoshi Ikeda and Junichi Higo$B!JEl5~Lt2JBg3X!K(B
$B!!(BWe studied the energy landscape of a peptide [Ace-Ala- His-Ser-Leu-Thr-Thr-Gly-Gln-Thr-Nme] with multicanonical MD simulation. This peptide sequence was derived from the 45$B!G(Bth to 53$B!G(Bth residues of the src SH3 domain. The conformation of the sequence in the SH3 domain is a $B&B(B-hairpin. The peptide was confined to a water sphere.
$B!!(BThe obtained energy landscape was separated into some clusters of well-structured conformations as well as random ones. The probabilities of existence for each conformation at 300 K were 8% for the $B&B(B-hairpin, 18% for the $B&A(B-helix, and 68% for the random-coil. The current work showed that the peptide has a potential tendency to a-helix conformations, although it takes the $B&B(B-hairpin in the whole protein. In this study, the pathways for the structural changes among those conformations were discussed. And a possible pathway for the whole protein folding of the SH3 domain was also proposed with investigating the energy landscape.