比利時的生命科學(xué)家發(fā)現(xiàn)細菌有一種獨特的機制,，能抑制氧化對細胞的有害影響,。他們通過修飾大腸桿菌的DNA揭示了這種機制的存在，該機制能夠修復(fù)細胞中已經(jīng)被氧化破壞的蛋白。
科學(xué)家表示，在人類中也存在著一個相似的修復(fù)系統(tǒng),。這項研究結(jié)果發(fā)布在Science上。
蛋白質(zhì)是我們細胞最重要的成分,，它們能輔助細胞中的化學(xué)反應(yīng),，提供結(jié)構(gòu)支持，方便生物之間的交流,。然而,，對于氧化造成的有害影響，蛋白質(zhì)也是很敏感的,。研究人員表示,，這些蛋白質(zhì)都包含硫磺成分，并以半胱氨酸為基礎(chǔ),，此外這些蛋白的半胱氨酸堆積塊通常是以成對的形式出現(xiàn),。
但是，細胞中還含有其他的蛋白質(zhì),，其半胱氨酸堆積塊是單獨出現(xiàn)的。這些單獨的半胱氨酸對抗氧化的機制還不是很清楚,。直到現(xiàn)在,，科學(xué)家已經(jīng)在大腸桿菌中識別了蛋白DsbG 和DsbC在細胞中形成巧妙的修復(fù)裝置基礎(chǔ)的機制。當(dāng)?shù)鞍踪|(zhì)的半胱氨酸堆積塊被氧化破壞時,，其中的一個蛋白會負責(zé)修復(fù)破壞,。
這項研究闡明了細胞在面臨氧化破壞時自我保護的機制。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 20 November 2009:DOI: 10.1126/science.1179557
A Periplasmic Reducing System Protects Single Cysteine Residues from Oxidation
Matthieu Depuydt,1 Stephen E. Leonard,2 Didier Vertommen,1 Katleen Denoncin,1 Pierre Morsomme,3 Khadija Wahni,4,5 Joris Messens,4,5 Kate S. Carroll,2 Jean-Fran?ois Collet1,*
The thiol group of the amino acid cysteine can be modified to regulate protein activity. The Escherichia coli periplasm is an oxidizing environment in which most cysteine residues are involved in disulfide bonds. However, many periplasmic proteins contain single cysteine residues, which are vulnerable to oxidation to sulfenic acids and then irreversibly modified to sulfinic and sulfonic acids. We discovered that DsbG and DsbC, two thioredoxin-related proteins, control the global sulfenic acid content of the periplasm and protect single cysteine residues from oxidation. DsbG interacts with the YbiS protein and, along with DsbC, regulates oxidation of its catalytic cysteine residue. Thus, a potentially widespread mechanism controls sulfenic acid modification in the cellular environment.
1 de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium.
2 Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109–1048, USA.
3 Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
4 Department of Molecular and Cellular Interactions, Vlaams Instituut voor Biotechnologie (VIB), Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
5 Structural Biology Brussels, Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
