title: The [Fe-Fe]-hydrogenase maturation protein HydF from Thermotoga maritima is a GTPase with an iron-sulfur cluster.
abstract: The active site of [Fe-Fe]-hydrogenases is composed of a di-iron complex, where the two metal atoms are bridged together by a putative di(thiomethyl)amine molecule and are also ligated by di-nuclear ligands, namely carbon monoxide and cyanide. Biosynthesis of this metal site is thought to require specific protein machinery coded by the hydE, hydF, and hydG genes. The HydF protein has been cloned from the thermophilic organism Thermotoga maritima, purified, and characterized. The enzyme possesses specific amino acid signatures for GTP binding and is able to hydrolyze GTP. The anaerobically reconstituted TmHydF protein binds a [4Fe-4S] cluster with peculiar EPR characteristics: an S = 1/2 signal presenting a high field shifted g-value together with a S = 3/2 signal, similar to those observed for [4Fe-4S] clusters ligated by only three cysteines. HYSCORE spectroscopy experiments were carried out to determine the nature of the fourth ligand of the cluster, and its exchangeability was demonstrated with the formation of a [4Fe-4S]-imidazole complex.
authors.affiliation: Laboratoire de Chimie et Biochimie des Centres Rédox Biologiques, UMR Université Joseph Fourier/CNRS/Commissariat à l'Energie Atomique-No. 5047, Grenoble, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Brazzolotto
authors.forename: Jon K
authors.initials: JK
authors.lastname: Rubach
authors.forename: Jacques
authors.initials: J
authors.lastname: Gaillard
authors.forename: Serge
authors.initials: S
authors.lastname: Gambarelli
authors.forename: Mohamed
authors.initials: M
authors.lastname: Atta
authors.forename: Marc
authors.initials: M
authors.lastname: Fontecave
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D020558:GTP Phosphohydrolases / Q000737:chemistry* / Q000502:physiology*; D006160:Guanosine Triphosphate / Q000737:chemistry; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D007093:Imidazoles / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008956:Models, Chemical; D015233:Models, Statistical; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D020124:Thermotoga maritima / Q000201:enzymology*; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D007093:Imidazoles; D007506:Iron-Sulfur Proteins; D008024:Ligands; D011994:Recombinant Proteins; C029899:imidazole; D006160:Guanosine Triphosphate; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; D020558:GTP Phosphohydrolases