TRYPTOPHAN REGULATED EXPRESSION AND AQUEOUS 2-PHASE SEPARATION OF RECOMBINANT HIV-FUSION PEPTIDES

This study investigates the expression and separation of a recombinant HIV/-beta-gal fusion protein expressed in Escherichia coli under trp promoter control. Product expression and its sensitivity to proteolyti c degradation are correlated with inducer strength and protease activi ty. Two previously unreported proteolytic activities of 42 and 55 kDa molecular weight were revealed which were shown to have activity towar ds beta-gal. Furthermore, by taking advantage of the extreme partition ing behavior of beta-galactosidase, the HIV-beta-gal fusion was separa ted and partially purified in a polyethylene glycol-potassium phosphat e aqueous two-phase system. Additionally, the 55 kDa protease with bet a-gal specificity partitioned into the salt-rich bottom phase. (C) 199 7 by Elsevier Science Inc.