脂質二重層におけるグラミシジンチャネル形成の動態学:トランスメブランのモノマー結合

A M O'Connell¹, R E Koeppe, O S Andersen

¹Department of Physiology and Biophysics, Cornell University Medical College, New York, NY 10021.

Science (New York, N.Y.)

|November 30, 1990

まとめ

グラミシジンチャネルは,脂質二重層に結合したモノマーから形成される. 異なったグラミシジンのモノマーによって形成されたハイブリッドチャネルが優勢で,グラミシジンが膜不浸透であることを示しています.

科学分野:

バイオフィジックス生物物理学
メンブラン生物学メンブラン生物学
イオンチャンネル形成

背景:

グラミシジンチャネルは,膜輸送を理解する上で極めて重要です.
これらのチャネルは,脂質二重層の間のモノマーの結合によって形成されることが知られている.
以前の研究では,グラミシジンの類型によってホモディメアチャンネルの形成が確認されました.

研究の目的:

ヘテロダイマー型グラミシジンチャネルの形成を調査する.
グラミシジンアナログの膜浸透性を決定するために.
ハイブリッドグラミシジンチャネルの伝導性を特徴付けるために.

主な方法:

平面性脂質二重層における単一チャネル電気生理学.
グラミシジンアナログ ([Val1]グラミシジンAおよび[4,4,4-F3-Val1]グラミシジンA) の非対称および対称的な添加は,事前形成された二重層に添加されます.
形成されたチャネルの導電性測定.

主要な成果:

化学的に異なったグラミシジンのモノマーによって形成されるハイブリッドチャネルは,グラミシジンが非対称的に加えられた場合の主なチャネルタイプでした.
[Val1]gramicidin Aと[4,4,4-F3-Val1]gramicidin Aの構造的に等価なホモディメアチャネルは,異なる伝導性を示した.
実験により,水害性のグラミシジンは驚くほど膜に浸透しないことが確認されました.

結論:

グラミシジンチャネル形成は,主に脂質二重層の間のモノマー結合によって引き起こされます.
ハイブリッドチャネルの形成は,異なったモノメアの結合能力を強調しています.
グラミシジンの低膜透透性は,そのチャネル形成機構に影響を与える重要な特徴です.

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