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

Prakash, Balaji ; Murthy, M. R. N. (1997) Source and target enzyme signature in serine protease inhibitor active site sequences Journal of Biosciences, 22 (5). pp. 555-565. ISSN 0250-5991

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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 here 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:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Protease Inhibitors; Active Site; Sequence Signature; Evolution; Convergence
ID Code:36945
Deposited On:28 Apr 2011 05:53
Last Modified:17 May 2016 19:52

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