Korormicin insensitivity in Vibrio alginolyticus is correlated with a single point mutation of Gly-140 in the NqrB subunit of the <f>Na<superscript>+</superscript></f>-translocating NADH-quinone reductase
In: Archives of Biochemistry & Biophysics, Jg. 401 (2002-05-15), Heft 2, S. 173-177
Online
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Zugriff:
Na+ -translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus is strongly inhibited by a new antibiotic korormicin. Korormicin specifically inhibits the Na+ -dependent reaction of the NQR complex and acts as a purely non-competitive inhibitor for Q-1 with the inhibitor constant of 82 pM. Korormicin-resistant mutants were isolated from V. alginolyticus and the NQR complex was purified from a mutant KR2. Similar to 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), korormicin acted as a purely noncompetitive inhibitor to the NQR complex from the mutant KR2, but the inhibitor constant increased to 8 μM , which is 105 -fold higher than that of the wild-type NQR complex. The inhibitor constant of HQNO, however, was only slightly affected by the acquisition of korormicin resistance. The spontaneous mutation was caused by a single mutation of G-422 to T-422 in the nucleotide sequence of the nqrB gene, which resulted in the conversion of Gly-140 to Val-140. Thus, Gly-140 seems to play an important role for the binding of korormicin to the NqrB subunit. The fact that korormicin is a purely noncompetitive inhibitor for Q-1 strongly supports the presence of one of Q-1 binding sites in the NqrB subunit, which also has a covalently bound FMN at Thr-235. [Copyright &y& Elsevier]
Titel: |
Korormicin insensitivity in Vibrio alginolyticus is correlated with a single point mutation of Gly-140 in the NqrB subunit of the <f>Na<superscript>+</superscript></f>-translocating NADH-quinone reductase
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Autor/in / Beteiligte Person: | Hayashi, Maki ; Shibata, Naoaki ; Nakayama, Yuji ; Yoshikawa, Kazuhiro ; Unemoto, Tsutomu |
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Zeitschrift: | Archives of Biochemistry & Biophysics, Jg. 401 (2002-05-15), Heft 2, S. 173-177 |
Veröffentlichung: | 2002 |
Medientyp: | academicJournal |
ISSN: | 0003-9861 (print) |
DOI: | 10.1016/S0003-9861(02)00007-3 |
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