Froehlich B J, Karakashian A, Melsen L R, Wakefield J C, Scott J R
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322.
Mol Microbiol. 1994 May;12(3):387-401. doi: 10.1111/j.1365-2958.1994.tb01028.x.
Many strains of enterotoxigenic Escherichia coli (ETEC) isolated from patients with diarrhoeal disease exhibit CS1 pili on their surfaces. These appendages, which are thought to be important for colonization of the upper intestine, are composed largely of multiple identical protein subunits encoded by cooA. We have sequenced the DNA directly downstream of cooA and identified two open reading frames, cooC and cooD, transcribed in the same direction as cooB and cooA. Following cooD is DNA homologous to an insertion sequence, so cooB, A, C and D appear to encode all the information needed for E. coli K-12 to synthesize CS1 pili. Complementation analysis of mutants cloned in E. coli K-12 and constructed in an ETEC-derived strain indicates that cooC and cooD are not required for stability of the major CS1 pilin protein or for its transport to the periplasm, but, like cooB, both are needed for assembly of cooA into pili.
从腹泻病患者中分离出的许多产肠毒素大肠杆菌（ETEC）菌株在其表面呈现CS1菌毛。这些附属物被认为对上段肠道的定植很重要，主要由cooA编码的多个相同蛋白质亚基组成。我们对cooA下游的DNA进行了直接测序，并鉴定出两个开放阅读框cooC和cooD，它们与cooB和cooA的转录方向相同。cooD之后是与插入序列同源的DNA，因此cooB、A、C和D似乎编码了大肠杆菌K-12合成CS1菌毛所需的所有信息。对克隆于大肠杆菌K-12并构建于一株ETEC衍生菌株中的突变体进行的互补分析表明，cooC和cooD对于主要CS1菌毛蛋白的稳定性或其转运到周质并非必需，但与cooB一样，二者对于cooA组装成菌毛都是必需的。
