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The C‐terminal region of the S component of Staphylococcal leukocidin is essential for the biological activity of the toxin
Author(s) -
Nariya Hirofumi,
Izaki Kazuo,
Kamio Yoshiyuki
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80225-j
Subject(s) - leukocidin , toxin , staphylococcus aureus , chemistry , biological activity , conformational change , residue (chemistry) , tryptophan , stereochemistry , fluorescence , excited state , binding site , biophysics , biochemistry , biology , bacteria , methicillin resistant staphylococcus aureus , amino acid , physics , in vitro , quantum mechanics , nuclear physics , genetics
The Staphylococcal toxin leukocidin consists of two protein components, F and S. From a culture medium of Staphylococcus aureus RIMD 310925, we isolated a truncated form of S (LS 2 ), of which the C‐terminal 17‐residue segment is missing. Unlike intact S, LS 2 showed neither leukocytolytic activity in the presence of F nor affinity for monosialoganglioside G M1 (G M1 ). When excited at 280 nm, both S and LS 2 exhibited intrinsic tryptophan fluorescence with an emission maximum at 318 nm. Upon binding to G M1 , the emission maximum of S underwent a blue shift to 310 nm, whereas no change in fluorescence took place on mixing G M1 with LS 2 . We conclude that the C‐terminal region of S is essential for its biological activity as well as for its binding to G M1 and that this binding is accompanied by a conformational change of the S protein.