Proteases of HIV-1 and MAV Hydrolyze Specifically Human Apo-Hemopexin

Abstract

The specificities of HIV-1 (Human Immunodeficiency Virus Type 1) and MAV (Myeloblastosis Associated Virus) proteases have been evaluated for their ability to split two-domain protein human apo-hemopexin. Both proteases hydrolyze only one peptidic bond Leu240-Ser241located in the connecting region between two domains. The ability of viral proteases to cleave Leu-Ser bond was confirmed by cleavage of synthetic octapeptide His-Leu-Val-Leu-Ser-Ala-Leu-Thr-NH2covering the susceptible area of human apo-hemopexin. The results demonstrate that the cleavage of Leu-Ser bond is not due to its location in the interdomain region of apo-hemopexin. The cleavable bond Leu-Ser has never been found either in viral or in non-viral proteins. According to the vector projection method this octapeptide was considered as non-hydrolyzable.