translation agency

Activation of modified anthrax toxin by HIV-1 protease.
Klimpel K; Leppla SH; National Institute of Dental Research, Bethesda,
December 30, 1995
Natl Conf Hum Retroviruses Relat Infect (1st). 1993 Dec 12-16;:126.

Protective antigen (PA), a protein component from anthrax toxin, must be cleaved in order to intoxicate cells. After binding to its receptor, a cell associated protease recognizes and cleaves PA after the amino acid sequence RKKR. We used cassette mutagenesis to replace residues 164167 (RKKR) of PA with five different sequences expected to be recognized by HIV-1 protease. The resulting recombinant proteins were expressed in Bacillus anthraces and purified from the culture supernatant (table: see text). Recombinant HIV-1 protease was used to digest each PA mutant in vitro. PAHIV No's 1, 2, 3 and 4 were all cleaved by the protease while PAHIV No. 5 was not. Cleavage was apparent in as little as 5 min. PAHIV No. 3 was cleaved the most efficiently followed by PAHIV No. 1 and PAHIV No. 2. When PA or PAHIV proteins were incubated with the HIV-1 protease for more than 60 min an unexpected second cleavage occurred. This may represent cleavage of PA and PAHIV proteins at residues 256VAAYPIVHV264. In addition to potential anti- viral applications, PAHIV proteins may be valuable tools for studying the action of the HIV-1 protease and its inhibitors in the context of a whole protein.

Amino Acid Sequence Bacterial Toxins/*METABOLISM HIV Protease/*METABOLISM HIV-1/*ENZYMOLOGY Molecular Sequence Data Mutagenesis, Insertional Recombinant Proteins/METABOLISM ABSTRACT