Viral cysteine proteases are homologous to the trypsin-like family of serine proteases: structural and functional implications - PubMed (original) (raw)

Viral cysteine proteases are homologous to the trypsin-like family of serine proteases: structural and functional implications

J F Bazan et al. Proc Natl Acad Sci U S A. 1988 Nov.

Abstract

Proteases that are encoded by animal picornaviruses and plant como- and potyviruses form a related group of cysteine-active-center enzymes that are essential for virus maturation. We show that these proteins are homologous to the family of trypsin-like serine proteases. In our model, the active-site nucleophile of the trypsin catalytic triad, Ser-195, is changed to a Cys residue in these viral proteases. The other two residues of the triad, His-57 and Asp-102, are otherwise absolutely conserved in all the viral protease sequences. Secondary structure analysis of aligned sequences suggests the location of the component strands of the twin beta-barrel trypsin fold in the viral proteases. Unexpectedly, the 2a and 3c subclasses of viral cysteine proteases are, respectively, homologous to the small and large structural subclasses of trypsin-like serine proteases. This classification allows the molecular mapping of residues from viral sequences onto related tertiary structures; we precisely identify amino acids that are strong determinants of specificity for both small and large viral cysteine proteases.

PubMed Disclaimer

Similar articles

Cited by

References

    1. J Mol Biol. 1987 Jul 5;196(1):199-216 - PubMed
    1. J Mol Biol. 1978 Dec 5;126(2):141-58 - PubMed
    1. Nucleic Acids Res. 1984 Mar 26;12(6):2969-85 - PubMed
    1. Comput Appl Biosci. 1988 Mar;4(1):61-6 - PubMed
    1. Proc Natl Acad Sci U S A. 1984 Jan;81(1):155-9 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources