5b57

Publication Abstract from PubMed

Pathogenic bacteria remove iron from the haem of host tissues and use it as a catalytic center of many enzymes. Haem uptake by pathogenic bacteria is facilitated by the membrane-integrated haem importer, which belongs to the type II ATP-binding cassette (ABC) transporter. Here we present crystal structures of Burkholderia cenocepacia haem importer BhuUV complexed with the periplasmic haem-binding protein BhuT and in the absence of BhuT. The transmembrane helices of these structures show an inward-facing conformation, in which the cytoplasmic gate of the haem translocation pathway is completely open. Since this conformation is found in both the haem- and nucleotide-free form, the structure of BhuUV-T provides the post-translocation state and the missing piece in the transport cycle of the type II importer. Structural comparison with the outward-facing conformation reported for the haem importer ortholog HmuUV from Yersenia pestis gives mechanistic insights into conformational transitions and haem secretion during the haem transport cycle.

Crystal structure of bacterial haem importer complex in the inward-facing conformation.,Naoe Y, Nakamura N, Doi A, Sawabe M, Nakamura H, Shiro Y, Sugimoto H Nat Commun. 2016 Nov 10;7:13411. doi: 10.1038/ncomms13411. PMID:27830695^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.