Myers C R, Myers J M
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA.
Lett Appl Microbiol. 2003;37(3):254-8. doi: 10.1046/j.1472-765x.2003.01389.x.
To determine if the outer membrane (OM) cytochromes of the metal-reducing bacterium Shewanella oneidensis MR-1 are exposed on the cell surface.
MR-1 cells were incubated with proteinase K or buffer and the resulting degradation of the OM cytochromes was examined by Western blotting. The periplasmic fumarate reductase (control) was not degraded. The OM cytochromes OmcA and OmcB were significantly degraded by proteinase K (71 and 31%, respectively). Immunofluorescence confirmed a prominent cell surface exposure of OmcA and a partial exposure of OmcB and the noncytochrome OM protein MtrB.
The cytochromes OmcA and OmcB are exposed on the outer face of the OM.
The cell surface exposure of these cytochromes could allow them to directly contact extracellular insoluble electron acceptors (e.g. manganese oxides) and is consistent with their in vivo role.
确定金属还原菌嗜温栖热放线菌MR-1的外膜（OM）细胞色素是否暴露于细胞表面。
将MR-1细胞与蛋白酶K或缓冲液孵育，通过蛋白质印迹法检测OM细胞色素的降解情况。周质延胡索酸还原酶（对照）未被降解。蛋白酶K可显著降解OM细胞色素OmcA和OmcB（分别为71%和31%）。免疫荧光证实OmcA在细胞表面显著暴露，OmcB和非细胞色素OM蛋白MtrB部分暴露。
细胞色素OmcA和OmcB暴露于OM的外表面。
这些细胞色素在细胞表面的暴露可使其直接接触细胞外不溶性电子受体（如锰氧化物），这与其在体内的作用相符。
