Identification of Biofilm Matrix-Associated Proteins from an Acid Mine Drainage Microbial Community
Identification of Biofilm Matrix-Associated Proteins from an Acid Mine Drainage Microbial Community
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DOI：
10.1128/aem.03005-10
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发表时间：
2011-08-01
影响因子：
4.4
通讯作者：
Thelen, Michael P.
中科院分区：
文献类型：
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作者：
Jiao, Yongqin;D'haeseleer, Patrik;Thelen, Michael P.
在微生物群落中，胞外聚合物(EPS)，也称为细胞外基质，在生物膜发育过程中提供空间组织和结构稳定性。EPS的主要成分之一是蛋白质，但目前尚不清楚这些蛋白质对细胞外基质或微生物生理有哪些具体功能。为了在极端酸性环境中的生物膜中研究这一点，我们使用鸟枪蛋白质组学分析来确定两个发育阶段的生物膜中与EPS相关的蛋白质，命名为DS1和DS2。EPS的蛋白质组组成与细胞组分显著不同，80%以上的细胞蛋白在EPS中表达不足或检测不到。相反，预测的周质、外膜和细胞外蛋白在EPS中的表达高出3-7倍。此外，EPS蛋白的碱性更强，平均类似于2个pH单位，长度约为其一半。当按预测功能分类时，参与运动、防御、细胞膜和未知功能的蛋白质在EPS中丰富。伴侣蛋白如组蛋白样DNA结合蛋白和冷休克蛋白在EPS中高表达。还检测到了蛋白质多肽酶、二硫键异构酶以及与细胞壁和多糖代谢有关的酶。其中两种酶分别为β-N-乙酰氨基己糖苷酶和纤维素酶，经酶活测定证实存在于EPS组分中。与EPS和细胞组分的差异相比，DS1和DS2的EPS蛋白质组的相对差异较小，与生物膜发育过程中预期的生理变化一致。
In microbial communities, extracellular polymeric substances (EPS), also called the extracellular matrix, provide the spatial organization and structural stability during biofilm development. One of the major components of EPS is protein, but it is not clear what specific functions these proteins contribute to the extracellular matrix or to microbial physiology. To investigate this in biofilms from an extremely acidic environment, we used shotgun proteomics analyses to identify proteins associated with EPS in biofilms at two developmental stages, designated DS1 and DS2. The proteome composition of the EPS was significantly different from that of the cell fraction, with more than 80% of the cellular proteins underrepresented or undetectable in EPS. In contrast, predicted periplasmic, outer membrane, and extracellular proteins were overrepresented by 3- to 7-fold in EPS. Also, EPS proteins were more basic by similar to 2 pH units on average and about half the length. When categorized by predicted function, proteins involved in motility, defense, cell envelope, and unknown functions were enriched in EPS. Chaperones, such as histone-like DNA binding protein and cold shock protein, were overrepresented in EPS. Enzymes, such as protein peptidases, disulfide-isomerases, and those associated with cell wall and polysaccharide metabolism, were also detected. Two of these enzymes, identified as beta-N-acetylhexosaminidase and cellulase, were confirmed in the EPS fraction by enzymatic activity assays. Compared to the differences between EPS and cellular fractions, the relative differences in the EPS proteomes between DS1 and DS2 were smaller and consistent with expected physiological changes during biofilm development.