3CP8

Crystal structure of GidA from Chlorobium tepidum

Summary for 3CP8

• Entry DOI: 10.2210/pdb3cp8/pdb
• Related: 3CP2
• Descriptor: tRNA uridine 5-carboxymethylaminomethyl modification enzyme gidA, FLAVIN-ADENINE DINUCLEOTIDE (2 entities in total)
• Functional Keywords: rossmann fold, fad-binding domain, dinucleotide-binding motif, glutathione reductase, oxido-reductase, trna-modification, cytoplasm, flavoprotein, trna processing, oxidoreductase
• Biological source: Chlorobium tepidum
• Cellular location: Cytoplasm (By similarity): Q8KA85
• Total number of polymer chains: 4
• Total formula weight: 284571.01

Authors

Meyer, S.,Scrima, A.,Versees, W.,Wittinghofer, A. (deposition date: 2008-03-31, release date: 2008-06-24, Last modification date: 2023-11-01)

Primary citation

Meyer, S.,Scrima, A.,Versees, W.,Wittinghofer, A.
Crystal structures of the conserved tRNA-modifying enzyme GidA: implications for its interaction with MnmE and substrate
J.Mol.Biol., 380:532-547, 2008

PubMed Abstract: GidA is a flavin-adenine-dinucleotide (FAD)-binding protein that is conserved among bacteria and eucarya. Together with MnmE, it is involved in the addition of a carboxymethylaminomethyl group to the uridine base in the wobble position (nucleotide 34) of tRNAs that read split codon boxes. Here, we report the crystal structures of the GidA proteins from both Escherichia coli and Chlorobium tepidum. The structures show that the protein can be divided into three domains: a first FAD-binding domain showing the classical Rossmann fold, a second alpha/beta domain inserted between two strands of the Rossmann fold, and an alpha-helical C-terminal domain. The domain inserted into the Rossmann fold displays structural similarity to the nicotinamide-adenine-dinucleotide-(phosphate)-binding domains of phenol hydroxylase and 3-hydroxy-3-methylglutaryl-CoA reductase, and, correspondingly, we show that GidA binds NADH with high specificity as an initial donor of electrons. GidA behaves as a homodimer in solution. As revealed by the crystal structures, homodimerization is mediated via both the FAD-binding domain and the NADH-binding domain. Finally, a large patch of highly conserved, positively charged residues on the surface of GidA leading to the FAD-binding site suggests a tRNA-binding surface. We propose a model for the interaction between GidA and MnmE, which is supported by site-directed mutagenesis. Our data suggest that this interaction is modulated and potentially regulated by the switch function of the G domain of MnmE.

PubMed: 18565343
DOI: 10.1016/j.jmb.2008.04.072

Experimental method

X-RAY DIFFRACTION (3.2 Å)