FEBS Letters | |
Identification of the minimum segment in which the threonine246 residue is a potential phosphorylated site by protein kinase A for the LukS‐specific function of staphylococcal leukocidin | |
Nariya, Hirofumi1  Kamio, Yoshiyuki1  Nishiyama, Akihito1  | |
[1] Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Amamiya-machi, Tsutsumi-dori, Aoba-ku, Sendai 981, Japan | |
关键词: Staphylococcal leukocidin; γ-Hemolysin; Bi-component cytolysin; LukS; Hlg2; Toxin phosphorylated by protein kinase A; LukS; LukS component of leukocidin; LukF; LukF component of leukocidin/γ-hemolysin; Hlg2; Hlg2 component of γ-hemolysin; PMSF; phenylmethylsulfonyl fluoride; | |
DOI : 10.1016/S0014-5793(97)01100-9 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Staphylococcal leukocidin and γ-hemolysin consist of LukF and LukS for leukocidin and LukF and Hlg2 for γ-hemolysin. In this report, we identify the minimum segment responsible for the LukS-specific function of leukocidin. After chemical analysis and homology study of the amino acid sequence of the C-terminal region between LukS and Hlg2, we found a unique 5-residue sequence I242K243R244S245T246 in LukS in which the 4-residue KRST is identical with that of the phosphorylated segment of a protein phosphorylated by protein kinase A. To elucidate whether the 5-residue segment is essential for the LukS function, we created plasmids containing a series of mutant genes corresponding to the 5-residue sequence and expressed them in Escherichia coli. The mutant proteins were purified and assayed for their leukocytolytic activity with LukF. The mutant MLS-TS, in which the T246 in the 5-residue sequence was replaced by S, showed leukocidin activity 10 times higher than that of the intact LukS. However, neither mutant MLS-TY nor MLS-TA, in which T246 was replaced by Y or A, respectively, showed leukocidin activity. The 5-residue segment was found to be deleted in Hlg2. The mutant of Hlg2, in which the 5-residue segment was inserted at the position that the segment is deleted, showed leukocidin activity. The boiled LukS, MLS-TS, and MHS-Z were strongly phosphorylated with [γ-32P]ATP in the presence of protein kinase A in a cell-free system. Thus, we conclude that the 5-residue segment I242K243R244S245T246 is the pivotal segment of LukS responsible for the LukS function of staphylococcal leukocidin.
【 授权许可】
Unknown
【 预 览 】
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