Lema M W, Brown A
Research Service, 151, Dorn Veterans Hospital, Columbia, SC, USA.
Curr Microbiol. 1995 Dec;31(6):332-5. doi: 10.1007/BF00294694.
Legionella pneumophila is a thermotolerant bacterium. To learn more about the thermal adaptation of this organism, we studied the properties of the Legionella 60-kDa heat-shock protein (MopA, GroEL-analog, HtpB, Lp-Hsp60) in L. pneumophila and in an Escherichia coli strain containing the cloned gene. Lp-Hsp60 was found in both cytosol and membrane fractions; however, Lp-Hsp60 in the membrane fraction of L. pneumophila was slightly larger than Lp-Hsp60 in the cytosol. In contrast, both membrane-associated and cytosolic Lp-Hsp60 in the E. coli clone were similar in size to the smaller cytosolic Lp-Hsp60 of L. pneumophila. While peptide mapping suggests there are differences between the two proteins, the larger membrane-associated Lp-Hsp60 and the smaller cytosolic LP-Hsp60 shared Legionella-specific and E. coli GroEL cross-reacting epitopes, and the sequence of their first 20 N-terminal amino acids was identical. Further, Southern blot analysis of EcoRI-digested chromosomal DNA from several strains of L. pneumophila showed two fragments reacting with an htpAB-operon probe. In summary, L. pneumophila contains two Hsp60 proteins, and possibly two hsp60 genes.
嗜肺军团菌是一种耐热细菌。为了更深入了解这种生物体的热适应性，我们研究了嗜肺军团菌以及含有克隆基因的大肠杆菌菌株中军团菌60 kDa热休克蛋白（MopA、GroEL类似物、HtpB、Lp-Hsp60）的特性。在细胞质和膜组分中均发现了Lp-Hsp60；然而，嗜肺军团菌膜组分中的Lp-Hsp60略大于细胞质中的Lp-Hsp60。相比之下，大肠杆菌克隆中与膜相关和细胞质中的Lp-Hsp60大小均与嗜肺军团菌中较小的细胞质Lp-Hsp60相似。虽然肽图谱分析表明这两种蛋白质存在差异，但较大的与膜相关的Lp-Hsp60和较小的细胞质Lp-Hsp60共享军团菌特异性和大肠杆菌GroEL交叉反应表位，且它们前20个N端氨基酸的序列相同。此外，对几种嗜肺军团菌菌株经EcoRI消化的染色体DNA进行的Southern印迹分析显示，有两个片段与htpAB操纵子探针发生反应。总之，嗜肺军团菌含有两种Hsp60蛋白，可能还有两个hsp60基因。
