Kuen B, Koch A, Asenbauer E, Sará M, Lubitz W
Institute of Microbiology and Genetics, Biocenter Vienna, Austria.
J Bacteriol. 1997 Mar;179(5):1664-70. doi: 10.1128/jb.179.5.1664-1670.1997.
S-layer protein variation from a hexagonally ordered (SbsA; 130 kDa) to a obliquely ordered (SbsB; 98 kDa) protein in Bacillus stearothermophilus PV72 is mediated by an increased oxygen supply. To elucidate the molecular basis of S-layer protein variation in B. stearothermophilus PV72, the sbsB gene, coding for the 98-kDa protein, was cloned by means of inverse PCR technology and sequenced. The sbsB coding region cloned in pUC18 was expressed in Escherichia coli, without its own regulatory upstream sequences but with its putative transcriptional terminator. The reading frame of sbsB (2,760 nucleotides) is predicted to encode a protein of 920 amino acids, including the signal sequence. Amino acid sequence comparison of SbsA and SbsB did not reveal any significant homology. The expression of sbsB in E. coli resulted in an accumulation of SbsB self-assembly products in the cytoplasm.
嗜热脂肪芽孢杆菌PV72中S层蛋白从六方有序（SbsA；130 kDa）到斜方有序（SbsB；98 kDa）的变化是由氧气供应增加介导的。为阐明嗜热脂肪芽孢杆菌PV72中S层蛋白变化的分子基础，通过反向PCR技术克隆了编码98 kDa蛋白的sbsB基因并进行测序。克隆到pUC18中的sbsB编码区在大肠杆菌中表达，没有其自身的上游调控序列，但有其假定的转录终止子。sbsB的阅读框（2760个核苷酸）预计编码一个含920个氨基酸的蛋白，包括信号序列。SbsA和SbsB的氨基酸序列比较未发现任何显著同源性。sbsB在大肠杆菌中的表达导致SbsB自组装产物在细胞质中积累。
