3IIX

X-ray structure of the FeFe-hydrogenase maturase HydE from T. maritima in complex with methionine and 5'deoxyadenosine

Summary for 3IIX

• Entry DOI: 10.2210/pdb3iix/pdb
• Related: 3CIW 3CIX 3IIZ
• Descriptor: [FeFe] hydrogenase maturase subunit HydE, IRON/SULFUR CLUSTER, METHIONINE, ... (9 entities in total)
• Functional Keywords: adomet radical, sam radical, adomet cleavage, fe4s4 cluster, hyde, hydrogenase, maturation, beta barrel, deoxyadenosine, adomet binding protein
• Biological source: Thermotoga maritima MSB8
• Total number of polymer chains: 1
• Total formula weight: 44028.40

Authors

Nicolet, Y.,Amara, P.,Mouesca, J.M.,Fontecilla-Camps, J.C. (deposition date: 2009-08-03, release date: 2009-09-22, Last modification date: 2023-11-22)

Primary citation

Nicolet, Y.,Amara, P.,Mouesca, J.-M.,Fontecilla-Camps, J.C.
Unexpected electron transfer mechanism upon AdoMet cleavage in radical SAM proteins
Proc.Natl.Acad.Sci.USA, 2009

PubMed Abstract: Radical 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 [Fe4S4] 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 [Fe4S4] 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 [Fe4S4] cluster. This unusual electron transfer is determined by the sulfonium ion in AdoMet.

PubMed: 19706452
DOI: 10.1073/pnas.0904385106

Experimental method

X-RAY DIFFRACTION (1.25 Å)