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| - | [[Image:2cn4.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2cn4| PDB=2cn4 | SCENE= }} | | {{STRUCTURE_2cn4| PDB=2cn4 | SCENE= }} |
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| - | '''THE CRYSTAL STRUCTURE OF THE SECRETED DIMERIC FORM OF THE HEMOPHORE HASA REVEALS A DOMAIN SWAPPING WITH AN EXCHANGED HEME LIGAND'''
| + | ===THE CRYSTAL STRUCTURE OF THE SECRETED DIMERIC FORM OF THE HEMOPHORE HASA REVEALS A DOMAIN SWAPPING WITH AN EXCHANGED HEME LIGAND=== |
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| - | ==Overview==
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| - | To satisfy their iron needs, several Gram-negative bacteria use a heme uptake system involving an extracellular heme-binding protein called hemophore. The function of the hemophore is to acquire free or hemoprotein-bound heme and to transfer it to HasR, its specific outer membrane receptor, by protein-protein interaction. The hemophore HasA secreted by Serratia marcescens, an opportunistic pathogen, was the first to be identified and is now very well characterized. HasA is a monomer that binds one b heme with strong affinity. The heme in HasA is highly exposed to solvent and coordinated by an unusual pair of ligands, a histidine and a tyrosine. Here, we report the identification, the characterization and the X-ray structure of a dimeric form of HasA from S. marcescens: DHasA. We show that both monomeric and dimeric forms are secreted in iron deficient conditions by S. marcescens. The crystal structure of DHasA reveals that it is a domain swapped dimer. The overall structure of each monomeric subunit of DHasA is very similar to that of HasA but formed by parts coming from the two different polypeptide chains, involving one of the heme ligands. Consequently DHasA binds two heme molecules by residues coming from both polypeptide chains. We show here that, while DHasA can bind two heme molecules, it is not able to deliver them to the receptor HasR. However, DHasA can efficiently transfer its heme to the monomeric form that, in turn, delivers it to HasR. We assume that DHasA can function as a heme reservoir in the hemophore system.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_17113104}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 17113104 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_17113104}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Metal-binding]] | | [[Category: Metal-binding]] |
| | [[Category: Transport protein]] | | [[Category: Transport protein]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 22:33:25 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 00:59:37 2008'' |
Revision as of 21:59, 28 July 2008
Template:STRUCTURE 2cn4
THE CRYSTAL STRUCTURE OF THE SECRETED DIMERIC FORM OF THE HEMOPHORE HASA REVEALS A DOMAIN SWAPPING WITH AN EXCHANGED HEME LIGAND
Template:ABSTRACT PUBMED 17113104
About this Structure
2CN4 is a Single protein structure of sequence from Serratia marcescens. Full crystallographic information is available from OCA.
Reference
The crystal structure of the secreted dimeric form of the hemophore HasA reveals a domain swapping with an exchanged heme ligand., Czjzek M, Letoffe S, Wandersman C, Delepierre M, Lecroisey A, Izadi-Pruneyre N, J Mol Biol. 2007 Jan 26;365(4):1176-86. Epub 2006 Oct 25. PMID:17113104
Page seeded by OCA on Tue Jul 29 00:59:37 2008
