Ghigo J M, Létoffé S, Wandersman C
Unité de Physiologie Cellulaire, Institut Pasteur (CNRS URA 1300), Paris, France.
J Bacteriol. 1997 Jun;179(11):3572-9. doi: 10.1128/jb.179.11.3572-3579.1997.
The utilization by Serratia marcescens of heme bound to hemoglobin requires HasA, an extracellular heme-binding protein. This unique heme acquisition system was studied in an Escherichia coli hemA mutant that was a heme auxotroph. We identified a 92-kDa iron-regulated S. marcescens outer membrane protein, HasR, which alone enabled the E. coli hemA mutant to grow on heme or hemoglobin as a porphyrin source. The concomitant secretion of HasA by the HasR-producing hemA mutant greatly facilitates the acquisition of heme from hemoglobin. This is the first report of a synergy between an outer membrane protein and an extracellular heme-binding protein, HasA, acting as a heme carrier, which we termed a hemophore.
粘质沙雷氏菌对与血红蛋白结合的血红素的利用需要HasA，一种细胞外血红素结合蛋白。在作为血红素营养缺陷型的大肠杆菌hemA突变体中研究了这种独特的血红素获取系统。我们鉴定出一种92 kDa的铁调节粘质沙雷氏菌外膜蛋白HasR，仅它就能使大肠杆菌hemA突变体在血红素或血红蛋白作为卟啉源的情况下生长。产生HasR的hemA突变体伴随分泌HasA极大地促进了从血红蛋白中获取血红素。这是关于外膜蛋白与作为血红素载体（我们称之为血胞素）的细胞外血红素结合蛋白HasA之间协同作用的首次报道。
