Heme uptake across the outer membrane as revealed by crystal structures of the receptor-hemophore complex. - Archive ouverte HAL Access content directly
Journal Articles Proceedings of the National Academy of Sciences of the United States of America Year : 2009

Heme uptake across the outer membrane as revealed by crystal structures of the receptor-hemophore complex.

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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.

Dates and versions

pasteur-00366353 , version 1 (06-03-2009)

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Stefanie Krieg, Frédéric Huché, Kay Diederichs, Nadia Izadi-Pruneyre, Anne Lecroisey, et al.. Heme uptake across the outer membrane as revealed by crystal structures of the receptor-hemophore complex.. Proceedings of the National Academy of Sciences of the United States of America, 2009, 106 (4), pp.1045-50. ⟨10.1073/pnas.0809406106⟩. ⟨pasteur-00366353⟩
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