Huesca M, Goodwin A, Bhagwansingh A, Hoffman P, Lingwood C A
Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Infect Immun. 1998 Sep;66(9):4061-7. doi: 10.1128/IAI.66.9.4061-4067.1998.
The in vitro glycolipid binding specificity of the gastric pathogen Helicobacter pylori is altered to include sulfated glycolipids (sulfatides) following brief exposure of the organism to acid pH typical of the stomach. This change is prevented by anti-hsp70 antibodies, suggesting that hsp70 may be a stress-induced surface adhesin, mediating sulfatide recognition. To facilitate investigation of the role of hsp70 in attachment, we have cloned and sequenced the H. pylori hsp70 gene (dnaK). The hsp70 gene was identified by probing a cosmid DNA library made from H. pylori 439 with a PCR amplicon generated with oligonucleotides synthesized to highly conserved regions of dnaK. The 1.9-kb H. pylori hsp70 gene encodes a product of 616 amino acids. Primer extension analysis revealed a single transcription start site, while Northern blot analysis established that hsp70 was preferentially induced by low pH rather than by heat shock. The ability of H. pylori to alter its glycolipid binding specificity following exposure to low pH by upregulating hsp70 and by expressing hsp70 on the bacterial surface may provide a survival advantage during periods of high acid stress.
胃病原体幽门螺杆菌的体外糖脂结合特异性在该生物体短暂暴露于胃部典型的酸性pH值后会发生改变，从而包括硫酸化糖脂（硫脂）。抗hsp70抗体可阻止这种变化，这表明hsp70可能是一种应激诱导的表面黏附素，介导硫脂识别。为便于研究hsp70在黏附中的作用，我们克隆并测序了幽门螺杆菌的hsp70基因（dnaK）。通过用由合成的与dnaK高度保守区域的寡核苷酸产生的PCR扩增子探测由幽门螺杆菌439构建的黏粒DNA文库来鉴定hsp70基因。1.9kb的幽门螺杆菌hsp70基因编码一个616个氨基酸的产物。引物延伸分析揭示了一个单一的转录起始位点，而Northern印迹分析表明hsp70优先由低pH而非热休克诱导。幽门螺杆菌在暴露于低pH后通过上调hsp70并在细菌表面表达hsp70来改变其糖脂结合特异性的能力可能在高酸应激期间提供生存优势。
