Summary for 5K9G
| Entry DOI | 10.2210/pdb5k9g/pdb |
| Related | 5K95 |
| Descriptor | GTP cyclohydrolase FolE2, ZINC ION, 1,2-ETHANEDIOL, ... (6 entities in total) |
| Functional Keywords | hydrolase, biosynthetic protein |
| Biological source | Neisseria gonorrhoeae (strain ATCC 700825 / FA 1090) |
| Total number of polymer chains | 2 |
| Total formula weight | 58419.19 |
| Authors | Alvarez, J.,Stec, B.,Swairjo, M.A. (deposition date: 2016-05-31, release date: 2016-09-07, Last modification date: 2024-11-06) |
| Primary citation | Paranagama, N.,Bonnett, S.A.,Alvarez, J.,Luthra, A.,Stec, B.,Gustafson, A.,Iwata-Reuyl, D.,Swairjo, M.A. Mechanism and catalytic strategy of the prokaryotic-specific GTP cyclohydrolase-IB. Biochem.J., 474:1017-1039, 2017 Cited by PubMed Abstract: Guanosine 5'-triphosphate (GTP) cyclohydrolase-I (GCYH-I) catalyzes the first step in folic acid biosynthesis in bacteria and plants, biopterin biosynthesis in mammals, and the biosynthesis of 7-deazaguanosine-modified tRNA nucleosides in bacteria and archaea. The type IB GCYH (GCYH-IB) is a prokaryotic-specific enzyme found in many pathogens. GCYH-IB is structurally distinct from the canonical type IA GCYH involved in biopterin biosynthesis in humans and animals, and thus is of interest as a potential antibacterial drug target. We report kinetic and inhibition data of GCYH-IB and two high-resolution crystal structures of the enzyme; one in complex with the reaction intermediate analog and competitive inhibitor 8-oxoguanosine 5'-triphosphate (8-oxo-GTP), and one with a tris(hydroxymethyl)aminomethane molecule bound in the active site and mimicking another reaction intermediate. Comparison with the type IA enzyme bound to 8-oxo-GTP (guanosine 5'-triphosphate) reveals an inverted mode of binding of the inhibitor ribosyl moiety and, together with site-directed mutagenesis data, shows that the two enzymes utilize different strategies for catalysis. Notably, the inhibitor interacts with a conserved active-site Cys149, and this residue is S-nitrosylated in the structures. This is the first structural characterization of a biologically S-nitrosylated bacterial protein. Mutagenesis and biochemical analyses demonstrate that Cys149 is essential for the cyclohydrolase reaction, and S-nitrosylation maintains enzyme activity, suggesting a potential role of the -nitrosothiol in catalysis. PubMed: 28126741DOI: 10.1042/BCJ20161025 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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