bacillus anthracis secretes proteins that mediate heme acquisition from hemoglobin炭疽杆菌分泌蛋白调节血红素从血红蛋白.pdf

Bacillus anthracis Secretes Proteins That Mediate Heme Acquisition from Hemoglobin Anthony W. Maresso, Gabriella Garufi, Olaf Schneewind* Department of Microbiology, University of Chicago, Chicago, Illinois, United States of America Abstract Acquisition of iron is necessary for the replication of nearly all bacterial pathogens; however, iron of vertebrate hosts is mostly sequestered by heme and bound to hemoglobin within red blood cells. In Bacillus anthracis, the spore-forming agent of anthrax, the mechanisms of iron scavenging from hemoglobin are unknown. We report here that B. anthracis secretes IsdX1 and IsdX2, two NEAT domain proteins, to remove heme from hemoglobin, thereby retrieving iron for bacterial growth. Unlike other Gram-positive bacteria, which rely on cell wall anchored Isd proteins for heme scavenging, B. anthracis seems to have also evolved NEAT domain proteins in the extracellular milieu and in the bacterial envelope to provide for the passage of heme. Citation: Maresso AW, Garufi G, Schneewind O (2008) Bacillus anthracis Secretes Proteins That Mediate Heme Acquisition from Hemoglobin. PLoS Pathog 4(8): e1000132. doi:10.1371/journal.ppat.1000132 Editor: Theresa Koehler, The University of Texas-Houston Medical School, United States of America Received February 5, 2008; Accepted July 22, 2008; Published August 22, 2008 Copyright: 2008 Maresso et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The authors acknowledge membership within and support from the Region V ‘‘Great Lakes’’ Regional Center of Excellence in Biodefense and Emerging Infectious Diseases Consortium (GLRCE, National