Download MendeleyHeme uptake across the outer membrane as revealed by crystal structures of the receptor-hemophore complex.
Krieg, S., Huche, F., Diederichs, K., Izadi-Pruneyre, N., Lecroisey, A., Wandersman, C., Delepelaire, P., Welte, W.(2009) Proc Natl Acad Sci U S A 106: 1045-1050
- PubMed: 19144921
- DOI: https://doi.org/10.1073/pnas.0809406106
- Primary Citation of Related Structures:
3CSL, 3CSN, 3DDR - PubMed Abstract:
Gram-negative bacteria use specific heme uptake systems, relying on outer membrane receptors and excreted heme-binding proteins (hemophores) to scavenge and actively transport heme. To unravel the unknown molecular details involved, we present 3 structures of the Serratia marcescens receptor HasR in complex with its hemophore HasA. The transfer of heme over a distance of 9 A from its high-affinity site in HasA into a site of lower affinity in HasR is coupled with the exergonic complex formation of the 2 proteins. Upon docking to the receptor, 1 of the 2 axial heme coordinations of the hemophore is initially broken, but the position and orientation of the heme is preserved. Subsequently, steric displacement of heme by a receptor residue ruptures the other axial coordination, leading to heme transfer into the receptor.
Organizational Affiliation:
Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany.
