Miyamoto M, Maeda H, Kitanaka M, Kokeguchi S, Takashiba S, Murayama Y
Department of Periodontology and Endodontology, Okayama University Dental School, Japan.
FEMS Microbiol Lett. 1998 Sep 15;166(2):275-81. doi: 10.1111/j.1574-6968.1998.tb13901.x.
The gene encoding the crystalline surface layer (S-layer) protein from Campylobacter rectus, designated slp, was sequenced and the recombinant gene product was expressed in Escherichia coli. The gene consisted of 4086 nucleotides encoding a protein with 1361 amino acids. The N-terminal amino acid sequence revealed that Slp did not contain a signal sequence, but that the initial methionine residue was processed. The deduced amino acid sequence displayed some common characteristic features of S-layer proteins previously reported. A homology search showed a high similarity to the Campylobacter fetus S-layer proteins, especially in their N-terminus. The C-terminal third of Slp exhibited homology with the RTX toxins from Gram-negative bacteria via the region including the glycine-rich repeats. The Slp protein had the same N-terminal sequence as a 104-kDa cytotoxin isolated from the culture supernatants of C. rectus. However, neither native nor recombinant Slp showed cytotoxicity against HL-60 cells or human peripheral white blood cells. These data support the idea that the N-terminus acts as an anchor to the cell surface components and that the C-terminus is involved in the assembly and/or transport of the protein.
对弯曲直肠杆菌编码晶体表面层（S层）蛋白的基因（命名为slp）进行了测序，并在大肠杆菌中表达了重组基因产物。该基因由4086个核苷酸组成，编码一个含有1361个氨基酸的蛋白质。N端氨基酸序列显示Slp不包含信号序列，但起始甲硫氨酸残基被加工。推导的氨基酸序列显示出先前报道的S层蛋白的一些共同特征。同源性搜索显示与胎儿弯曲杆菌S层蛋白高度相似，尤其是在它们的N端。Slp的C端三分之一通过包括富含甘氨酸重复序列的区域与革兰氏阴性菌的RTX毒素具有同源性。Slp蛋白与从弯曲直肠杆菌培养上清液中分离出的104 kDa细胞毒素具有相同的N端序列。然而，天然的和重组的Slp对HL-60细胞或人外周血白细胞均未显示出细胞毒性。这些数据支持这样的观点，即N端作为细胞表面成分的锚定物，而C端参与蛋白质的组装和/或运输。
