Mullen Lisa M, Bossé Janine T, Nair Sean P, Ward John M, Rycroft Andrew N, Robertson Giles, Langford Paul R, Henderson Brian
Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, United Kingdom.
PLoS One. 2008;3(12):e3991. doi: 10.1371/journal.pone.0003991. Epub 2008 Dec 22.
A novel fibronectin-binding protein from Pasteurella multocida (PM1665) that binds to the fibronectin type III(9-10) modules via two helix-hairpin-helix motifs has recently been described [1]. This protein shares homology with competence-related DNA-binding and uptake proteins (ComEA and ComE) from Gram-positive and Gram-negative bacteria. Here, we show that recombinant PM1665 (now designated ComE1) also binds to DNA through the same helix-hairpin-helix motifs required for fibronectin-binding. This binding to DNA is non sequence-specific and is confined to double-stranded DNA. We have cloned and expressed ComE1 proteins from five members of the Pasteurellaceae in order to further investigate the function(s) of these proteins. When expressed as recombinant GST-fusion proteins, all of the homologues bound both to fibronectin and to double-stranded DNA. Inactivation of the gene encoding the ComE1 homologue in Actinobacillus pleuropneumoniae indicates major roles for these proteins in at least two processes: natural transformation, and binding of bacteria to fibronectin.
最近有报道称，多杀性巴氏杆菌中一种新型的纤连蛋白结合蛋白（PM1665）可通过两个螺旋-发夹-螺旋基序与III型纤连蛋白（9-10）模块结合[1]。该蛋白与革兰氏阳性菌和革兰氏阴性菌中与感受态相关的DNA结合及摄取蛋白（ComEA和ComE）具有同源性。在此，我们表明重组PM1665（现命名为ComE1）也通过纤连蛋白结合所需的相同螺旋-发夹-螺旋基序与DNA结合。这种与DNA的结合是非序列特异性的，且仅限于双链DNA。我们克隆并表达了巴斯德菌科五个成员的ComE1蛋白，以进一步研究这些蛋白的功能。当表达为重组GST融合蛋白时，所有同源物均能与纤连蛋白和双链DNA结合。胸膜肺炎放线杆菌中编码ComE1同源物的基因失活表明，这些蛋白在至少两个过程中起主要作用：自然转化以及细菌与纤连蛋白的结合。
