Interdomain hydrolysis of a truncated Pseudomonas exotoxin by the human immunodeficiency virus-1 protease.

摘要: The specificity of HIV-1 (human immunodeficiency virus-1) protease has been evaluated relative to its ability cleave the three-domain Pseudomonas exotoxin (PE66) and related proteins in which first domain deleted or replaced by a segment CD4. Native PE66 is not hydrolyzed protease. However, removal produces molecule an excellent substrate for enzyme. major site cleavage this truncated exotoxin, called LysPE40, occurs that connects two domains, translocation (II), ADP-ribosyltransferase (III). This interdomain region contains sequence ...Asn-Tyr-Pro-Thr... similar surrounding scissile Tyr-Pro bond gag precursor polyprotein, natural Nevertheless, it recognized cleaved enzyme, but one 6 residues away, ...Ala-Leu-Leu-Glu... Leu-Leu peptide hydrolyzed. A second, slower takes place at Leu-Ala 3 from NH2 terminus LysPE40. When I comprising domains CD4, resulting chimeric protein same Enzyme activities toward synthetic peptides modeled after sequences defined above LysPE40 are complete accord, specificity, kinetics, pH optimum, with results obtained hydrolysis parent protein. These findings demonstrate ideas concerning based solely upon processing viral polyproteins can be expanded evaluation other multidomain as substrates. Moreover, would appear particular conformation, accessibility play dominant role defining sites susceptible