科學(xué)家早就知道漂白劑有獨(dú)特的殺菌能力,，從廚房細(xì)菌到致命的炭疽病毒都不在話下，但并不太清楚其中的原理,。美國科學(xué)家最近的一項(xiàng)研究表明,，漂白劑破壞了細(xì)菌蛋白質(zhì)從而殺死細(xì)菌，研究人員稱這一研究可能有助于生產(chǎn)毒性小的新型殺菌劑,。相關(guān)研究發(fā)表在11月14日的《細(xì)胞》（Cell）上,。
漂白劑中的重要成分是次氯酸,。先前的假說認(rèn)為次氯酸離子從細(xì)菌那里“偷取”了電子，這一氧化過程擾亂了細(xì)菌體內(nèi)關(guān)鍵的化學(xué)反應(yīng)?，F(xiàn)在一項(xiàng)新研究表明,，除了前述的過程之外，次氯酸還攻擊了細(xì)菌體內(nèi)特定的蛋白質(zhì),，使蛋白質(zhì)展開并功能失常,。
美國密歇根大學(xué)生物化學(xué)家Ursula Jakob與她的同事一起研究一種稱為Hsp33的蛋白質(zhì)，研究人員意外發(fā)現(xiàn),，在漂白劑的作用下,，這種蛋白質(zhì)不但沒有功能失常，反而開啟了功能,。Hsp33屬于脅迫蛋白（stress protein）,，這種蛋白保護(hù)細(xì)胞不受外界如熱、酸之類的刺激,，過去的實(shí)驗(yàn)認(rèn)為Hsp33通過阻止其他蛋白質(zhì)展開后凝塊而發(fā)揮作用,。Hsp33這一令人困惑的表現(xiàn)促使研究人員研究漂白劑對蛋白質(zhì)的作用。
研究人員將具有和不具有Hsp33的大腸桿菌置于不同濃度的漂白劑中,，觀測細(xì)菌蛋白質(zhì)如何反應(yīng),。具有Hsp33的細(xì)菌表現(xiàn)出了較少的凝塊現(xiàn)象，并能在較高濃度漂白劑中存活更長時(shí)間,。這一發(fā)現(xiàn)表明漂白劑殺菌是靠展開（unfold）蛋白質(zhì)并使其粘在一起,，即蛋白質(zhì)聚集（protein aggregation）。
理解漂白劑作用于細(xì)胞的機(jī)理可以幫助研究人員開發(fā)毒性小的,、無化學(xué)副作用的殺菌劑,。耶魯大學(xué)分子生物學(xué)家Arthur Horwich認(rèn)為，進(jìn)一步的工作可能揭示細(xì)菌是如何抵抗殺菌劑和哺乳動(dòng)物免疫細(xì)胞的,，這些細(xì)胞中有一些也能用次氯酸殺滅細(xì)菌,。（生物谷Bioon.com）
生物谷推薦原始出處：
Cell， Volume 135,， Issue 4,， 691-701，J. Winter,，M. Ilbert
leach Activates a Redox-Regulated Chaperone by Oxidative Protein Unfolding
J. Winter1,3,4,M. Ilbert1,3,P.C.F. Graf1,2,5,D. ?zcelik1andU. Jakob1,2,,
1 Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
2 Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
3 These authors contributed equally to this work
4 Present address: Institut für Biotechnologie, Department Chemie, Technische Universit?t München, Garching, Germany
5 Present address: Infectious Diseases Directorate, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA
SUMMARY
Hypochlorous acid (HOCl), the active ingredient in household bleach, is an effective antimicrobial produced by the mammalian host defense to kill invading microorganisms. Despite the widespread use of HOCl, surprisingly little is known about its mode of action. In this study, we demonstrate that low molar ratios of HOCl to protein cause oxidative protein unfolding invitro and target thermolabile proteins for irreversible aggregation invivo. As a defense mechanism, bacteria use the redox-regulated chaperone Hsp33, which responds to bleach treatment with the reversible oxidative unfolding of its C-terminal redox switch domain. HOCl-mediated unfolding turns inactive Hsp33 into a highly active chaperone holdase, which protects essential Escherichia coli proteins against HOCl-induced aggregation and increases bacterial HOCl resistance. Our results substantially improve our molecular understanding about HOCl's functional mechanism. They suggest that the antimicrobial effects of bleach are largely based on HOCl's ability to cause aggregation of essential bacterial proteins.
