Structural highlights
Function
[HASA_SERMA] Can bind free heme and also acquire it from hemoglobin. Conveys heme from hemoglobin to the HasR receptor which releases it into the bacterium. HasR alone can take up heme but the synergy between HasA and HasR increases heme uptake 100-fold.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The protein HasA from the Gram negative bacteria Serratia marcescens is the first hemophore to be described at the molecular level. It participates to the shuttling of heme from hemoglobin to the outer membrane receptor HasR, which in turn releases it into the bacterium. HasR alone is also able to take up heme from hemoglobin but synergy with HasA increases the efficiency of the system by a factor of about 100. This iron acquisition system allows the bacteria to survive with hemoglobin as the sole iron source. Here we report the structures of a new crystal form of HasA diffracting up to 1.77A resolution as well as the refined structure of the trigonal crystal form diffracting to 3.2A resolution. The crystal structure of HasA at high resolution shows two possible orientations of the heme within the heme-binding pocket, which probably are functionally involved in the heme-iron acquisition process. The detailed analysis of the three known structures reveals the molecular basis regulating the relative affinity of the heme/hemophore complex.
Functional aspects of the heme bound hemophore HasA by structural analysis of various crystal forms.,Arnoux P, Haser R, Izadi-Pruneyre N, Lecroisey A, Czjzek M Proteins. 2000 Nov 1;41(2):202-10. PMID:10966573[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Letoffe S, Ghigo JM, Wandersman C. Iron acquisition from heme and hemoglobin by a Serratia marcescens extracellular protein. Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):9876-80. PMID:7937909
- ↑ Ghigo JM, Letoffe S, Wandersman C. A new type of hemophore-dependent heme acquisition system of Serratia marcescens reconstituted in Escherichia coli. J Bacteriol. 1997 Jun;179(11):3572-9. PMID:9171402
- ↑ Arnoux P, Haser R, Izadi-Pruneyre N, Lecroisey A, Czjzek M. Functional aspects of the heme bound hemophore HasA by structural analysis of various crystal forms. Proteins. 2000 Nov 1;41(2):202-10. PMID:10966573
