Biozentrum der Universität Basel, Basel, Switzerland. Department of Biomedicine, University Hospital Basel, Basel, Switzerland.
Mol Microbiol. 2011 Aug;81(4):1050-60. doi: 10.1111/j.1365-2958.2011.07750.x. Epub 2011 Jul 18.
Capnocytophaga canimorsus are commensal Gram-negative bacteria from dog's mouth that cause rare but dramatic septicaemia in humans. C. canimorsus have the unusual property to feed on cultured mammalian cells, including phagocytes, by harvesting the glycan moiety of cellular glycoproteins. To understand the mechanism behind this unusual property, the genome of strain Cc5 was sequenced and analysed. In addition, Cc5 bacteria were cultivated onto HEK 293 cells and the surface proteome was determined. The genome was found to encode many lipoproteins encoded within 13 polysaccharide utilization loci (PULs) typical of the Flavobacteria-Bacteroides group. PULs encode surface exposed feeding complexes resembling the archetypal starch utilization system (Sus). The products of at least nine PULs were detected among the surface proteome and eight of them represented more than half of the total peptides detected from the surface proteome. Systematic deletions of the 13 PULs revealed that half of these Sus-like complexes contributed to growth on animal cells. The complex encoded by PUL5, one of the most abundant ones, was involved in foraging glycans from glycoproteins. It was essential for growth on cells and contributed to survival in mice. It thus represents a fitness factor during infection.
噬二氧化碳噬纤维菌是一种常见于狗口腔中的革兰氏阴性共生菌，可导致人类罕见但严重的败血症。噬二氧化碳噬纤维菌具有一种不寻常的特性，能够通过从细胞糖蛋白的聚糖部分收获，来摄取包括吞噬细胞在内的培养哺乳动物细胞。为了了解这种不寻常特性背后的机制，对菌株 Cc5 的基因组进行了测序和分析。此外，还将 Cc5 细菌培养在 HEK 293 细胞上，并确定了表面蛋白质组。基因组编码了许多脂蛋白，这些脂蛋白编码在 13 个多糖利用基因座 (PUL) 内，这些 PUL 是黄杆菌-拟杆菌群的典型特征。PUL 编码类似于典型淀粉利用系统 (Sus) 的表面暴露的摄食复合物。至少有九个 PUL 的产物在表面蛋白质组中被检测到，其中八个占从表面蛋白质组中检测到的总肽的一半以上。13 个 PUL 的系统缺失显示，这些 Sus 样复合物中有一半有助于在动物细胞上生长。PUL5 编码的复合物是最丰富的复合物之一，参与从糖蛋白中寻找聚糖。它对细胞生长是必需的，并有助于在小鼠中的存活。因此，它是感染过程中的一个适应因素。
