Stojiljkovic I, Hantke K
Lehrstuhl Mikrobiologie II, Universität Tübingen, Germany.
EMBO J. 1992 Dec;11(12):4359-67. doi: 10.1002/j.1460-2075.1992.tb05535.x.
The hemin receptor HemR of Yersinia enterocolitica was identified as a 78 kDa iron regulated outer membrane protein. Cells devoid of the HemR receptor as well as cells mutated in the tonB gene were unable to take up hemin as an iron source. The hemin uptake operon from Y. enterocolitica was cloned in Escherichia coli K12 and was shown to encode four proteins: HemP (6.5 kDa), HemR (78 kDa), HemS (42 kDa) and HemT (27 kDa). When expressed in E.coli hemA aroB, a plasmid carrying genes for HemP and HemR allowed growth on hemin as a porphyrin source. Presence of genes for HemP, HemR and HemS was necessary to allow E.coli hemA aroB cells to use hemin as an iron source. The nucleotide sequence of the hemR gene and its promoter region was determined and the amino acid sequence of the HemR receptor deduced. HemR has a signal peptide of 28 amino acids and a typical TonB box at its amino-terminus. Upstream of the first gene in the operon (hemP), a well conserved Fur box was found which is in accordance with the iron-regulated expression of HemR.
小肠结肠炎耶尔森菌的血红素受体HemR被鉴定为一种78 kDa的铁调节外膜蛋白。缺乏HemR受体的细胞以及tonB基因突变的细胞都无法摄取血红素作为铁源。小肠结肠炎耶尔森菌的血红素摄取操纵子被克隆到大肠杆菌K12中，结果显示它编码四种蛋白质：HemP（6.5 kDa）、HemR（78 kDa）、HemS（42 kDa）和HemT（27 kDa）。当在大肠杆菌hemA aroB中表达时，携带HemP和HemR基因的质粒能使细胞利用血红素作为卟啉源生长。HemP、HemR和HemS基因的存在是大肠杆菌hemA aroB细胞利用血红素作为铁源所必需的。测定了hemR基因及其启动子区域的核苷酸序列，并推导了HemR受体的氨基酸序列。HemR有一个28个氨基酸的信号肽，且在其氨基末端有一个典型的TonB框。在操纵子的第一个基因（hemP）上游，发现了一个保守性良好的Fur框，这与HemR的铁调节表达一致。
