Aromatic clusters: a determinant of thermal stability of thermophilic proteins

Kannan, N and Vishveshwara, S (2000) Aromatic clusters: a determinant of thermal stability of thermophilic proteins. In: Protein Engineering, 13 (11). pp. 753-761.

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Abstract

A number of factors have been elucidated as responsible for the thermal stability of thermophilic proteins. However, the contribution of aromatic interactions to thermal stability has not been systematically studied. In the present investigation we used a graph spectral method to identify aromatic clusters in a dataset of 24 protein families for which the crystal structures of both the thermophilic and their mesophilic homologues are known. Our analysis shows a presence of additional aromatic clusters or enlarged aromatic networks in 17 different thermophilic protein families, which are absent in the corresponding mesophilic homologue. The additional aromatic clusters identified in the thermophiles are smaller in size and are largely found on the protein surface. The aromatic clusters are found to be relatively rigid regions of the surface and often the additional aromatic cluster is located close to the active site of the thermophilic enzyme. The residues in the additional aromatic clusters are preferably mutated to Leu, Ser or Ile in the mesophilic homologue. An analysis of the packing geometry of the pairwise aromatic interaction in the additional aromatic clusters shows a preference for a T-shaped orthogonal packing geometry. The present study also provides new insights for protein engineers to design thermostable and thermophilic proteins.

Item Type:	Journal Article
Publication:	Protein Engineering
Publisher:	Oxford University Press
Additional Information:	Copyright of this article belongs to Oxford University Press.
Keywords:	Aromatic clusters;Aromatic packing;Protein engineering;Protein folding;Thermal stability
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	16 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12218

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