Programming the Rous sarcoma virus protease to cleave new substrate sequences.

Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.

Programming the Rous sarcoma virus protease to cleave new substrate sequences.

J Biol Chem. 1996 May 3;271(18):10538-44. Unique Identifier : AIDSLINE MED/96209975
Ridky TW; Bizub-Bender D; Cameron CE; Weber IT; Wlodawer A; Copeland T; Skalka AM; Leis J; Department of Biochemistry, Case Western Reserve University,; Cleveland, Ohio 44106, USA.

Abstract: The Rous sarcoma virus protease displays a high degree of specificity and catalyzes the cleavage of only a limited number of amino acid sequences. This specificity is governed by interactions between side chains of eight substrate amino acids and eight corresponding subsite pockets within the homodimeric enzyme. We have examined these complex interactions in order to learn how to introduce changes into the retroviral protease (PR) that direct it to cleave substrates. Mutant enzymes with altered substrate specificity and wild-type or greater catalytic rates have been constructed previously by substituting single key amino acids in each of the eight enzyme subsites with those residues found in structurally related positions of human immunodeficiency virus (HIV)-1 PR. These individual amino acid substitutions have now been combined into one enzyme, resulting in a highly active mutant Rous sarcoma virus (RSV) protease that displays many characteristics associated with the HIV-1 enzyme. The hybrid protease is capable of catalyzing the cleavage of a set of HIV-1 viral polyprotein substrates that are not recognized by the wild-type RSV enzyme. Additionally, the modified PR is inhibited completely by the HIV-1 PR-specific inhibitor KNI-272 at concentrations where wild-type RSV PR is unaffected. These results indicate that the major determinants that dictate RSV and HIV-1 PR substrate specificity have been identified. Since the viral protease is a homodimer, the rational design of enzymes with altered specificity also requires a thorough understanding of the importance of enzyme symmetry in substrate selection. We demonstrate here that the enzyme homodimer acts symmetrically in substrate selection with each enzyme subunit being capable of recognizing both halves of a peptide substrate equally.

Keywords: Aspartic Proteinases/GENETICS/*METABOLISM Base Sequence Cloning, Molecular Escherichia coli/GENETICS Hydrolysis HIV Protease Inhibitors/PHARMACOLOGY HIV-1/ENZYMOLOGY Molecular Sequence Data Oligopeptides/PHARMACOLOGY Substrate Specificity Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. JOURNAL ARTICLE
960930
M9690912

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