In silico analysis of amino acid sequences in relation to specificity and physiochemical properties of some microbial nitrilases

Abstract

In silico analysis of amino acid sequences of some aromatic and aliphatic microbial nitrilases for certain physiochemical properties and specificity to aromatic or aliphatic nitriles has been done. The multiple sequence alignment analysis of amino acid sequences has shown clear differences between aromatic and aliphatic nitrilases in terms of position specific presence of conserved amino acid. Statistical analysis of most of the physiochemical parameters did not show any clear distinction between the two nitrilases. In aromatic nitrilases the conserved amino acid residues besides active site domain triad (Glu, Lys, Cys) were His-129, Asn-168 and Arg-174 and these were replaced by Arg-129, His -168 and Lys-174 in aliphatic nitrilases. The physiochemical properties of these two groups of nitrilases also differed e.g. as compared to aliphatic nitrilases, aromatic nitrilases have lesser number of amino acid residues, lower molecular mass, higher pI values, higher content of Ala and Cys residues. © 2009 Nikhil S, et al.