Entrapment of a Water Wire in a Hydrophobic Peptide Channel with an Aromatic Lining

Raghavender, Upadhyayula Surya and Chatterjee, Bhaswati and Saha, Indranil and Rajagopal, Appavu and Shamala, Narayanaswamy and Balaram, Padmanabhan (2011) Entrapment of a Water Wire in a Hydrophobic Peptide Channel with an Aromatic Lining. In: Journal of Physical Chemistry B, 115 (29). pp. 9236-9243.

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Abstract

A one-dimensional water wire has been characterized by X-ray diffraction in single crystals of the tripeptide Ac-Phe-Pro-Trp-OMe. Crystals in the hexagonal space group P6(5) reveal a central hydrophobic channel lined by aromatic residues which entraps an approximately linear array of hydrogen bonded water molecules. The absence of any significant van der Waals contact with the channel walls suggests that the dominant interaction between the ``water wire'' and ``peptide nanotube'' is electrostatic in origin. An energy difference of 16 KJmol(-1) is estimated for the distinct orientations of the water wire dipole with respect to the macrodipole of the peptide nanotube. The structural model suggests that Grotthuss type proton conduction may, through constricted hydrophobic channels, be facilitated by concerted, rotational reorientation of water molecules.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry B
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	05 Aug 2011 08:25
Last Modified:	05 Aug 2011 08:26
URI:	http://eprints.iisc.ac.in/id/eprint/39730

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