# Energy minimization studies on \alpha -turns

Ramakrishnan, C and Nataraj, DV (1998) Energy minimization studies on \alpha -turns. In: Journal of Peptide Science, 4 (4). pp. 239-252.

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## Abstract

Using a grid search technique, the entire conformational space of a system of four linked peptide units (tetrapeptide) was scanned to pick out geometrically possible 5 \longrightarrow 1 type hydrogen-bonded conformations defined as an \alpha -turn. The energy minimization of these conformations led to 23 distinct minimum energy conformations (MECs) falling in 13 different classes. The presence of \beta and \gamma turn type hydrogen bonds along with 5 \longrightarrow 1 type hydrogen bond gave conformational variability in a given class. The occurrence of bifurcated hydrogen bonding network was a characteristic feature of most of the MECs. In many prototype MECs non-glycyl residues such as Ala and Pro could be accommodated. Comparison of MECs with the \alpha -turn examples that are observed in proteins showed that the conformationally worked out MECs occurred in isolation in proteins, with the \alpha -helical \alpha -turn being distinctly the most predominant.

Item Type: Journal Article The copyright belongs to European Peptide Society and John Wiley & Sons, Ltd. hydrogen bonded tetrapeptide;alpha turns;alpha turn conformation;energy minimization;secondary structure Division of Biological Sciences > Molecular Biophysics Unit 16 Jan 2006 27 Aug 2008 11:40 http://eprints.iisc.ernet.in/id/eprint/4993