Lee B C
Department of Microbiology and Infectious Diseases, University of Calgary, Alberta, Canada.
Infect Immun. 1992 Mar;60(3):810-6. doi: 10.1128/iai.60.3.810-816.1992.
Haemophilus influenzae is a heme-dependent bacterium. However, little is known of the heme-iron uptake mechanism in this organism. By using a batch ligand affinity chromatography method, a hemin-binding protein of 39,500 molecular weight was isolated from total membranes derived from H. influenzae type b grown under iron-depleted but not under iron-sufficient conditions. Detection of the hemin-binding protein in a whole-cell binding assay demonstrated a surface-exposed location. Competition binding experiments indicated that this hemin-protein interaction was specific, since only hemin or heme-containing proteins, such as human hemoglobin and bovine catalase, but not protoporphyrin IX, iron-loaded human lactoferrin, or transferrin, could abrogate binding. In a limited survey of other H. influenzae strains, an identical hemin-binding protein was isolated, implying that this polypeptide may be structurally and functionally conserved among strains.
流感嗜血杆菌是一种依赖血红素的细菌。然而，对于该生物体中血红素铁的摄取机制知之甚少。通过使用批量配体亲和色谱法，从在缺铁而非铁充足条件下生长的b型流感嗜血杆菌的总膜中分离出一种分子量为39,500的血红素结合蛋白。在全细胞结合试验中对血红素结合蛋白的检测表明其位于细胞表面。竞争结合实验表明这种血红素与蛋白质的相互作用是特异性的，因为只有血红素或含血红素的蛋白质，如人血红蛋白和牛过氧化氢酶，而不是原卟啉IX、铁负载的人乳铁蛋白或转铁蛋白，能够消除结合。在对其他流感嗜血杆菌菌株的有限调查中，分离出了相同的血红素结合蛋白，这意味着该多肽在菌株间可能在结构和功能上是保守的。
