Zhang Z, Li S, Huang C
Institute of Biotechnology, Academy of Military Medical Sciences, Beijing, China.
Chin J Biotechnol. 1993;9(1):57-61.
The structure gene of the colonization factor antigen 1 (CFA/1) has been sequenced. The amino acid sequence of CFA/1 precursor deduced from the nucleotide sequence is composed of 170 amino acids. The first 23 amino acids are considered to be the signal peptide of the CFA/1 protein. On the basis of the nucleotide sequence, three amino acids are different from the protein sequence. Amino acid residues at positions 37, 76 and 97 are found to be Ala, Asp and Ser, instead of Val, Asn and Ala as determined by amino acid sequencing. The CFA/1 is very hydrophobic amino acids. Among the total 170 amino acids, 47% of them are hydrophobic amino acids. CFA/1 gene has a typical Shine-Dalgarno sequence and-10 sequence, but no 35 promoter sequence could be found. The G + C ratio of CFA/1 gene is 40%. Observation of negatively stained preparations of the culture with electron microscopy showed that no fimbriae were found on E. coli C600 strain itself, but the cell carrying the plasmid showed thick pili on its surface.
定居因子抗原1（CFA/1）的结构基因已被测序。从核苷酸序列推导的CFA/1前体的氨基酸序列由170个氨基酸组成。前23个氨基酸被认为是CFA/1蛋白的信号肽。根据核苷酸序列，有三个氨基酸与蛋白质序列不同。发现第37、76和97位的氨基酸残基分别为丙氨酸、天冬氨酸和丝氨酸，而氨基酸测序确定为缬氨酸、天冬酰胺和丙氨酸。CFA/1是非常疏水的氨基酸。在总共170个氨基酸中，47%是疏水氨基酸。CFA/1基因有一个典型的Shine-Dalgarno序列和-10序列，但未发现35启动子序列。CFA/1基因的G+C比例为40%。用电子显微镜观察培养物的负染制剂，发现大肠杆菌C600菌株本身没有菌毛，但携带质粒的细胞表面有粗菌毛。
