50 - Moloney murine leukemia virus retropepsin

Abstract

This chapter elaborates the structural chemistry and the biological aspects of moloney Murine Leukemia Virus (MLV) retropepsin. Moloney MLV retropepsin was encoded by the gag-pol gene and synthesized through the suppression of the UAG termination codon found at the end of gag. This enzyme is also known as MLV retropepsin or MLV protease (or proteinase). Moloney MLV retropepsin is able to cleave efficiently synthetic peptides representing maturation sites found in polyproteins of other retroviruses. Moloney MLV and HIV retropepsins have similar enzymological properties. However, several specific inhibitors of HIV-1 retropepsin are less effective with the MLV proteases. MLV retropepsins are highly conserved and most of them share more than 95% identical amino acids with the Moloney MLV protease. Active feline LV retropepsin has been purified from virus. It shares 80% identical amino acids with Moloney MLV retropepsin. All of these enzymes appear to be very similar in terms of substrate specificity as suggested by comparison of the corresponding Gag cleavage site sequences in different viruses.