Aravinda, S and Shamala, N and Pramanik, Animesh and Das, Chittaranjan and Balaram, P (2000) An unusual C-H center dot center dot center dot O hydrogen bond mediated reversal of polypeptide chain direction in a synthetic peptide helix. In: Biochemical and Biophysical Research Communications, 273 (3). pp. 933-936.
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An unusual C-terminal conformation has been detected in a synthetic decapeptide designed to analyze the stereochemistry of helix termination in polypeptides. The crystal structure of the decapeptide Boc-Leu-Aib-Val-Ala-Leu-Aib-Val-(D)Ala-(D)Leu-Aib-OMe reveals a helical segment spanning residues 1-7 and helix termination by formation of a Schellman motif, generated by (D)Ala(8) adopting the left-handed helical (alpha(L)) conformation. The extended conformation at (D)Leu(9) results in a compact folded structure, stabilized by a potentially strong C-H ... O hydrogen bond between Ala(4) (CH)-H-alpha and (D)Leu(9)CO. The parameters for C-H ... O interaction are Ala(4) (CH)-H-alpha .. O=C (D)Leu(9) distance 3.27 Angstrom C-alpha-H .. O angle 176 degrees, and O .. H-alpha distance 2.29 Angstrom. This structure suggests that insertion of contiguous D-residues may provide a handle for the generation of designed structures containing more than one helical segment folded in a compact manner. (C) 2000 Academic Press.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science.|
|Keywords:||C-H··· O hydrogen bond;conformational analysis;helix termination;peptide design;Schellman motif;X-ray structure|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit
Division of Physical & Mathematical Sciences > Physics
|Date Deposited:||23 Aug 2010 06:34|
|Last Modified:||19 Sep 2010 06:14|
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