Identification of the minimum segment essential for the H gamma II-specific function of staphylococcal gamma-hemolysin.

Abstract

Staphylococcal gamma-hemolysin consists of H gamma I (or LukF) of 34 kDa and H gamma II of 32 kDa, which cooperatively lyse human erythrocytes. Our previous data showed that the N-terminal 57-residue segment of H gamma II is the essential region for the H gamma II function [H. Nariya and Y. Kamio, Biosci. Biotech. Biochem., 59, 1603-1604 (1995)]. To identify the minimum amino acid residues in the 57-residue segment responsible for the specific hemolytic activity, a series of mutant genes were constructed and expressed in Escherichia coli. The mutant proteins were purified and assayed for their hemolytic activity. The results indicate that the 5-residue segment (K23R24L25A26I27) of H gamma II is the minimum region essential for the H gamma II function.