Summary for 4FR0
| Entry DOI | 10.2210/pdb4fr0/pdb |
| Related | 4FS8 4FSD |
| Descriptor | Arsenic methyltransferase, S-ADENOSYLMETHIONINE (2 entities in total) |
| Functional Keywords | rossmann fold, arsenic methyltransferase, transferase |
| Biological source | Cyanidioschyzon sp. 5508 |
| Total number of polymer chains | 1 |
| Total formula weight | 42711.17 |
| Authors | Ajees, A.A.,Marapakala, K.,Packianathan, C.,Sankaran, B.,Rosen, B.P. (deposition date: 2012-06-26, release date: 2012-07-11, Last modification date: 2024-11-20) |
| Primary citation | Ajees, A.A.,Marapakala, K.,Packianathan, C.,Sankaran, B.,Rosen, B.P. Structure of an As(III) S-Adenosylmethionine Methyltransferase: Insights into the Mechanism of Arsenic Biotransformation. Biochemistry, 51:5476-5485, 2012 Cited by PubMed Abstract: Enzymatic methylation of arsenic is a detoxification process in microorganisms but in humans may activate the metalloid to more carcinogenic species. We describe the first structure of an As(III) S-adenosylmethionine methyltransferase by X-ray crystallography that reveals a novel As(III) binding domain. The structure of the methyltransferase from the thermophilic eukaryotic alga Cyanidioschyzon merolae reveals the relationship between the arsenic and S-adenosylmethionine binding sites to a final resolution of ∼1.6 Å. As(III) binding causes little change in conformation, but binding of SAM reorients helix α4 and a loop (residues 49-80) toward the As(III) binding domain, positioning the methyl group for transfer to the metalloid. There is no evidence of a reductase domain. These results are consistent with previous suggestions that arsenic remains trivalent during the catalytic cycle. A homology model of human As(III) S-adenosylmethionine methyltransferase with the location of known polymorphisms was constructed. The structure provides insights into the mechanism of substrate binding and catalysis. PubMed: 22712827DOI: 10.1021/bi3004632 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.75 Å) |
Structure validation
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