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From Proteopedia
X-ray structure of the FeFe-hydrogenase maturase HydE from T. maritima in complex with methionine and 5'deoxyadenosine
Structural highlights
FunctionHYDE_THEMA Required for the maturation of the [FeFe]-hydrogenase HydA (By similarity). Catalyzes the reductive cleavage of S-adenosyl-L-methionine (in vitro), suggesting it may contribute to the biosynthesis of an essential sulfur-containing ligand that binds to the hydrogenase active site [2Fe-2S] cluster (PubMed:16137685).[UniProtKB:Q97IK9][1] 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 PubMedRadical S-adenosine-L-methionine (SAM or AdoMet) proteins are involved in chemically difficult reactions including the synthesis of cofactors, the generation of protein radicals, and the maturation of complex organometallic catalytic sites. In the first and common step of the reaction, a conserved [Fe(4)S(4)] cluster donates an electron to perform the reductive cleavage of AdoMet into methionine and a reactive radical 5'-dA. species. The latter extracts a hydrogen atom from substrate eliciting one of the about 40 reactions so far characterized for this family of proteins. It has been suggested that the radical-generating mechanism differs depending on whether AdoMet is a cofactor or a substrate. It has also been speculated that electron transfer from the [Fe(4)S(4)] cluster to AdoMet is sulfur-based. Here we have used protein crystallography and theoretical calculations to show that regardless whether AdoMet serves as a cofactor or a substrate, the 5'-dA. generating mechanism should be common to the radical SAM proteins studied so far, and that electron transfer is mediated by a unique Fe from the conserved [Fe(4)S(4)] cluster. This unusual electron transfer is determined by the sulfonium ion in AdoMet. Unexpected electron transfer mechanism upon AdoMet cleavage in radical SAM proteins.,Nicolet Y, Amara P, Mouesca JM, Fontecilla-Camps JC Proc Natl Acad Sci U S A. 2009 Aug 17. PMID:19706452[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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