3AB9
Crystal Structure of lipoylated E. coli H-protein (reduced form)
Summary for 3AB9
| Entry DOI | 10.2210/pdb3ab9/pdb |
| Related | 1HPC 1HTP 3A8I 3A8J 3A8K |
| Descriptor | Glycine cleavage system H protein, CALCIUM ION, CHLORIDE ION, ... (4 entities in total) |
| Functional Keywords | glycine cleavage system, lipoyl, transport protein |
| Biological source | Escherichia coli |
| Total number of polymer chains | 1 |
| Total formula weight | 14084.95 |
| Authors | Okamura-Ikeda, K.,Maita, N. (deposition date: 2009-12-04, release date: 2010-04-07, Last modification date: 2023-11-01) |
| Primary citation | Okamura-Ikeda, K.,Hosaka, H.,Maita, N.,Fujiwara, K.,Yoshizawa, A.C.,Nakagawa, A.,Taniguchi, H. Crystal structure of aminomethyltransferase in complex with dihydrolipoyl-H-protein of the glycine cleavage system: implications for recognition of lipoyl protein substrate, disease-related mutations, and reaction mechanism J.Biol.Chem., 285:18684-18692, 2010 Cited by PubMed Abstract: Aminomethyltransferase, a component of the glycine cleavage system termed T-protein, reversibly catalyzes the degradation of the aminomethyl moiety of glycine attached to the lipoate cofactor of H-protein, resulting in the production of ammonia, 5,10-methylenetetrahydrofolate, and dihydrolipoate-bearing H-protein in the presence of tetrahydrofolate. Several mutations in the human T-protein gene are known to cause nonketotic hyperglycinemia. Here, we report the crystal structure of Escherichia coli T-protein in complex with dihydrolipoate-bearing H-protein and 5-methyltetrahydrofolate, a complex mimicking the ternary complex in the reverse reaction. The structure of the complex shows a highly interacting intermolecular interface limited to a small area and the protein-bound dihydrolipoyllysine arm inserted into the active site cavity of the T-protein. Invariant Arg(292) of the T-protein is essential for complex assembly. The structure also provides novel insights in understanding the disease-causing mutations, in addition to the disease-related impairment in the cofactor-enzyme interactions reported previously. Furthermore, structural and mutational analyses suggest that the reversible transfer of the methylene group between the lipoate and tetrahydrofolate should proceed through the electron relay-assisted iminium intermediate formation. PubMed: 20375021DOI: 10.1074/jbc.M110.110718 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.65 Å) |
Structure validation
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