Poster Presentation 2014 International Biophysics Congress

Local sequence of protein ß-strands influences twist and bend angles (#291)

Kazuo Fujiwara 1 , Shinichi Ebisawa 1 , Yuka Watanabe 1 , Masamichi Ikeguchi 1
  1. Soka University, Hachioji-shi, Tokio, Japan

ß-sheet twisting is thought to be mainly determined by inter-strand hydrogen bonds with little contribution from side chains, but some proteins have large, flat ß-sheets, suggesting that side chains influence ß-structures. We therefore investigated the relationship between amino acid composition and twists or bends of ß-strands. We calculated and statistically analyzed the twist and bend angles of short frames of ß-strands in known protein structures. The most frequent twist angles were strongly negatively correlated with the proportion of hydrophilic amino acid residues. The majority of hydrophilic residues (except serine and threonine) were found in the edge regions of ß-strands, suggesting that the side chains of these residues likely do not affect b-strand structure. In contrast, the majority of serine, threonine and asparagine side-chains in ß-strands made contacts with a nitrogen atom of the main chain, suggesting that these residues suppress ß-strand twisting.