Partial characterization of chorionic gonadotropin-like binding sites from the bacteria Xanthomonas maltophilia
Partial characterization of chorionic gonadotropin-like binding sites from the bacteria Xanthomonas maltophilia
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DOI：
10.1177/153537020322800808
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发表时间：
2003-09-01
影响因子：
3.2
通讯作者：
Odell, WD
中科院分区：
文献类型：
--
作者：
Edwards, JG;Odell, WD
革兰氏阴性菌，嗜麦芽黄单胞菌，具有低和高亲和力的促黄体激素/绒毛膜促性腺激素（LH/CG）结合位点，类似于哺乳动物中发现的LH/CG受体。虽然低亲和力位点结合LH和人CG（hCG），但高亲和力位点对hCG具有特异性。在目前的研究中，这两个结合位点独立地从X中分离出来。嗜麦芽窄食单胞菌进行进一步表征。为了分离功能性结合位点，我们开发了一种增溶方法，其使用去污剂Zwittergent 3，14和高甘油浓度，允许维持配体结合完整性。凝胶过滤实验建立了两个结合位点的分子量为170和11.5 kDa，这得到了光亲和标记和超离心实验数据的支持。凝胶过滤数据还表明存在5.4 kDa的第三个结合位点。170-kDa位点的结合亲和力为Kd = 12 × 10（-6），并结合LH和hCG。小分子量位点的亲和力为Kd = 9.4 × 10 ~（-8），并且是CG特异性的。总的来说，这些数据表明在X中存在多个激素结合位点。嗜麦芽窄食单胞菌，其在分子大小、结合亲和力和配体特异性上不同。
The gram-negative bacterium, Xanthomonas maltophilia, has low- and high-affinity luteinizing hormone/chorionic gonadotropin (LH/CG)-binding sites, similar to the LH/CG receptor found in mammals. Although the low-affinity site binds both LH and human CG (hCG), the high-affinity site is specific for hCG. In the current investigation, these two binding sites were independently isolated from X. maltophilia for further characterization. To isolate functional binding sites, we developed a solubilization method using the detergent zwittergent 3,14 and high glycerol concentrations that allowed for the maintenance of ligand-binding integrity. Gel filtration experiments established molecular weights of 170 and 11.5 kDa for the two binding sites, which were supported by data from photoaffinity labeling and ultracentrifugation experiments. Gel filtration data also suggested the presence of a third binding site of 5.4 kDa. The 170-kDa site had a binding affinity of Kd = 12 x 10(-6) and bound both LH and hCG. The small molecular weight site had an affinity of Kd = 9.4 x 10(-8) and was CG specific. Collectively, these data demonstrate the presence of multiple hormone binding sites in X. maltophilia that differ in molecular size, binding affinity, and ligand specificity.