Dissecting π‐helices: sequence, structure and function

• DOI: 10.1111/febs.13507
• Publication Date: 2015-09-15T12:05:50Z
• Authors: Prasun Kumar; Manju Bansal
• Keywords: Helix (gastropod); Folding (DSP implementation); Loop modeling

A new procedure for the identification of regular secondary structures using a C(α) trace has identified 659 π-helices in 3582 protein chains, solved at high resolution. Taking advantage this significantly expanded database π-helices, we have analysed functional and structural roles determined position-wise amino acid propensity within around them. These helices range from 5 to 18 residues length with average twist rise being 85.2 ± 7.2° 1.28 0.31 Å, respectively. total 546 (~ 83%) out occur conjunction α-helices, 101 interspersed between two α-helices. The majority were found be conserved across large number family produce significant bend overall helical segment as well local distortions neighbouring presence π-helical fragment leads appropriate orientation constituent residues, so facilitate favourable interactions also help proper folding chain. In addition intra 6→1 N-H···O hydrogen bonds, are stabilized by several other non-bonded interactions. π-Helices show distinct positional residue preferences, which different those