βバレルの組立機械の構造

Jeremy Bakelar¹, Susan K Buchanan², Nicholas Noinaj³

¹Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.

Science (New York, N.Y.)

|January 9, 2016

まとめ

バクテリアのベータ・バレル・アセンブリ・マシーン (BAM) の複雑な構造は,外膜タンパク質 (OMP) の組み立て方を示しています. この発見は,グラム陰性細菌におけるOMP生殖の調節とメカニズムについての洞察を提供します.

科学分野:

微生物学
構造生物学
生物化学

背景:

グラム陰性細菌はベータバレル外膜タンパク質 (OMP) を栄養素の吸収と粘着などの重要な機能に利用します.
ベータ・バレル・アセンブリ・マシーン (BAM) コンプレックスは,これらのOMPの生体生成に不可欠です.

研究の目的:

エシェリキア・コライのBAM複合体の構造を解明する.
BAM複合体の成分がどのように相互作用し,OMPの生体生成を調節するかを理解する.

主な方法:

BAM複合体の高解像度構造を決定するX線結晶学またはCryo-EM.
BAM成分と基質OMPの相互作用を調査する生化学的測定法.

主要な成果:

構造は,BamCDE結合が中央コンポーネントであるBamAの形状を調節することを明らかにし,規制メカニズムを示唆しています.
BamAの周回プラズマ領域は閉じた状態で,OMPがバレルを通過していないことを示しています.
バレルの領域の形状の変化は,出口孔を開き,横のゲートを再配置します.

結論:

決定された構造は,BAM複合調節のためのメカニズム的基礎を提供します.
発見は,OMPを外膜に挿入するための新しいメカニズムを示唆し,単純なスレッドから異なります.
この研究により細菌の外膜タンパク質の生成に関する理解が深まりました

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