The origin of ?-strand bending in globular proteins #MMPMID26492857
Fujiwara K; Ebisawa S; Watanabe Y; Fujiwara H; Ikeguchi M
BMC Struct Biol 2015[]; 15 (ä): ä PMID26492857show ga
Background: Many ?-strands are not flat but bend and/or twist. However, although almost all ?-strands have a twist, not all have a bend, suggesting that the underlying force(s) driving ?-strand bending is distinct from that for the twist. We, therefore, investigated the physical origin(s) of ?-strand bends. Methods: We calculated rotation, twist and bend angles for a four-residue short frame. Fixed-length fragments consisting of six residues found in three consecutive short frames were used to evaluate the twist and bend angles of full-length ?-strands. Results: We calculated and statistically analyzed the twist and bend angles of ?-strands found in globular proteins with known three-dimensional structures. The results show that full-length ?-strand bend angles are related to the nearby aromatic residue content, whereas local bend angles are related to the nearby aliphatic residue content. Furthermore, it appears that ?-strands bend to maximize their hydrophobic contacts with an abutting hydrophobic surface or to form a hydrophobic side-chain cluster when an abutting hydrophobic surface is absent. Conclusions: We conclude that the dominant driving force for full-length ?-strand bends is the hydrophobic interaction involving aromatic residues, whereas that for local ?-strand bends is the hydrophobic interaction involving aliphatic residues. Electronic supplementary material: The online version of this article (doi:10.1186/s12900-015-0048-y) contains supplementary material, which is available to authorized users.
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BMC+Struct+Biol 2015 ; 15 (ä): ä
