Gating the bacterial mechanosensitive channel MscL in vivo

Ann Finney Batiza, Mario Meng Chiang Kuo, Kenjiro Yoshimura, Ching Kung

研究成果: Article

51 引用 (Scopus)

抄録

YggB and MscL are the major mechanosensitive channels in Escherichia coli, and each can rescue the double knockout mutant from osmotic downshock. However, the role of MscL in wild-type bacteria is in question, not only because cells without MscL survive severe osmotic downshocks, but because 1.8 times more suction is required to gate MscL than YggB under patch clamp. Here, we extend previous evidence [Ajouz, B., Berrier, C., Garrigues, A., Besnard, M. & Ghazi, A. (1998) J. Biol. Chem. 273, 26670-26674] to show that downshock gates MscL in vivo even in the presence of YggB. We have made this determination by engineering a channel we can structurally modify in vivo (Leu-19→Cys MscL). MscLs with charges in their constrictions are known to open easily and transiently to substates and stop cell growth. In this study, we use downshock to stretch this region open to allow attachment of a charged thiosulfonate reagent MTSET+, thereby creating a toxic channel. Therefore, channel opening can be monitored by loss of colony forming units. By this measure, we find that an ≈800 mmol/kg downshock from 1,200 mmol/kg medium opens Leu-19→Cys MscL in the presence of YggB, but a downshock of only ≈400 mmol/kg is required in the absence of YggB. In parallel, Leu-19→Cys MscL, stretched open by large sustained suction in the presence of MTSET+ in voltage-clamped patches, subsequently flickers open with little suction. These observations show that MscL opening is triggered by a specific downshock, even in the presence of YggB, that YggB buffers MscL gating in vivo, and that residue 19 becomes exposed upon channel opening.

元の言語English
ページ(範囲)5643-5648
ページ数6
ジャーナルProceedings of the National Academy of Sciences of the United States of America
99
発行部数8
DOI
出版物ステータスPublished - 2002 4 16
外部発表Yes

ASJC Scopus subject areas

  • Genetics
  • General

これを引用

Gating the bacterial mechanosensitive channel MscL in vivo. / Batiza, Ann Finney; Kuo, Mario Meng Chiang; Yoshimura, Kenjiro; Kung, Ching.

:: Proceedings of the National Academy of Sciences of the United States of America, 巻 99, 番号 8, 16.04.2002, p. 5643-5648.

研究成果: Article

Batiza, Ann Finney ; Kuo, Mario Meng Chiang ; Yoshimura, Kenjiro ; Kung, Ching. / Gating the bacterial mechanosensitive channel MscL in vivo. :: Proceedings of the National Academy of Sciences of the United States of America. 2002 ; 巻 99, 番号 8. pp. 5643-5648.
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abstract = "YggB and MscL are the major mechanosensitive channels in Escherichia coli, and each can rescue the double knockout mutant from osmotic downshock. However, the role of MscL in wild-type bacteria is in question, not only because cells without MscL survive severe osmotic downshocks, but because 1.8 times more suction is required to gate MscL than YggB under patch clamp. Here, we extend previous evidence [Ajouz, B., Berrier, C., Garrigues, A., Besnard, M. & Ghazi, A. (1998) J. Biol. Chem. 273, 26670-26674] to show that downshock gates MscL in vivo even in the presence of YggB. We have made this determination by engineering a channel we can structurally modify in vivo (Leu-19→Cys MscL). MscLs with charges in their constrictions are known to open easily and transiently to substates and stop cell growth. In this study, we use downshock to stretch this region open to allow attachment of a charged thiosulfonate reagent MTSET+, thereby creating a toxic channel. Therefore, channel opening can be monitored by loss of colony forming units. By this measure, we find that an ≈800 mmol/kg downshock from 1,200 mmol/kg medium opens Leu-19→Cys MscL in the presence of YggB, but a downshock of only ≈400 mmol/kg is required in the absence of YggB. In parallel, Leu-19→Cys MscL, stretched open by large sustained suction in the presence of MTSET+ in voltage-clamped patches, subsequently flickers open with little suction. These observations show that MscL opening is triggered by a specific downshock, even in the presence of YggB, that YggB buffers MscL gating in vivo, and that residue 19 becomes exposed upon channel opening.",
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