Structural Basis for Biofilm Formation via the Vibrio cholerae Matrix Protein RbmA
Structural Basis for Biofilm Formation via the Vibrio cholerae Matrix Protein RbmA
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DOI：
10.1128/jb.00374-13
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发表时间：
2013-07-01
影响因子：
3.2
通讯作者：
Sondermann, Holger
中科院分区：
文献类型：
--
作者：
Giglio, Krista M.;Fong, Jiunn C.;Sondermann, Holger
在从自由游动的单细胞生活方式到称为生物膜的固着的多细胞状态的转变期间，细菌产生并分泌由核酸、胞外多糖和粘附蛋白组成的细胞外基质。霍乱弧菌生物膜基质含有三种主要的蛋白质组分，RbmA，Bap 1和RbmC，它们是霍乱弧菌所特有的，并且似乎在该过程的特定步骤中支持生物膜形成。在这里，我们专注于RbmA，一个未知的折叠结构蛋白。RbmA参与早期细胞-细胞粘附事件，并且在整个生物膜中发现，其中它定位于细胞-细胞接触位点。我们确定了晶体结构的RbmA和揭示的蛋白折叠成串联纤连蛋白III型（FnIII）的倍。该蛋白质在溶液和晶体中是二聚体，二聚体界面显示出表面沟槽，其内衬有几个带正电荷的残基。结构指导的诱变研究建立了一个至关重要的作用，这种表面补丁的RbmA功能。在结构的基础上，我们假设RbmA通过保持细胞和细胞外基质之间的灵活联系来充当系链。
During the transition from a free-swimming, single-cell lifestyle to a sessile, multicellular state called a biofilm, bacteria produce and secrete an extracellular matrix comprised of nucleic acids, exopolysaccharides, and adhesion proteins. The Vibrio cholerae biofilm matrix contains three major protein components, RbmA, Bap1, and RbmC, which are unique to Vibrio cholerae and appear to support biofilm formation at particular steps in the process. Here, we focus on RbmA, a structural protein with an unknown fold. RbmA participates in the early cell-cell adhesion events and is found throughout the biofilm where it localizes to cell-cell contact sites. We determined crystal structures of RbmA and revealed that the protein folds into tandem fibronectin type III (FnIII) folds. The protein is dimeric in solution and in crystals, with the dimer interface displaying a surface groove that is lined with several positively charged residues. Structure-guided mutagenesis studies establish a crucial role for this surface patch for RbmA function. On the basis of the structure, we hypothesize that RbmA serves as a tether by maintaining flexible linkages between cells and the extracellular matrix.