Cloning of the bovine leukemia virus proteinase in Escherichia coli and comparison of its specificity to that of human T-cell leukemia virus proteinase

The protinase of bovine leukemia virus (BLV) was cloned into pMal-c2 vector with N-terminal or with N- as well as C-terminal flanking sequences, and e xpressed in fusion with maltose binding protein. The proteinase self-proces sed itself from the fusion protein during expression and formed inclusion b odies. The enzyme was purified from inclusion bodies by cation-exchange chr omatography followed by gel filtration. Specificity of the enzyme was compa red to that of human T-cell leukemia proteinase type I. Although the two vi ruses belong to the same subfamily of retroviruses, the differences in thei r proteinase specificity, based on kinetics with oligopeptide substrates re presenting naturally occurring cleavage sites as well as on inhibition patt ern, appear to be pronounced. (C) 2000 Elsevier Science B.V. All rights res erved.