Source and target enzyme signature in serine protease inhibitor active site sequences

Prakash, B and Murthy, MRN (1997) Source and target enzyme signature in serine protease inhibitor active site sequences. In: Journal of Biosciences, 22 (5). pp. 555-565.

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Abstract

Amino acid sequences of proteinaceous proteinase inhibitors have been extensively analysed for deriving information regarding the molecular evolution and functional relationship of these proteins. These sequences have been grouped into several well defined families. It was found that the phylogeny constructed with the sequences corresponding to the exposed loop responsible for inhibition has several branches that resemble those obtained from comparisons using the entire sequence. The major branches of the unrooted tree corresponded to the families to which the inhibitors belonged. Further branching is related to the enzyme specificity of the inhibitor. Examination of the active site loop sequences of trypsin inhibitors revealed that there are strong preferences for specific amino acids at different positions of the loop. These preferences are inhibitor class specific. Inhibitors active against more than one enzyme occur within a class and confirm to class specific sequence in their loops. Hence, only a few positions in the loop seem to determine the specificity. The ability to inhibit the same enzyme by inhibitors that belong to different classes appears to be a result of convergent evolution

Item Type:	Journal Article
Publication:	Journal of Biosciences
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Protease inhibitors; active site; sequence signature; evolution; convergence.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	06 Jan 2011 06:12
Last Modified:	06 Jan 2011 06:12
URI:	http://eprints.iisc.ac.in/id/eprint/34096

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