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4FR0

ArsM arsenic(III) S-adenosylmethionine methyltransferase with SAM

Replaces:  3QHU
Summary for 4FR0
Entry DOI10.2210/pdb4fr0/pdb
Related4FS8 4FSD
DescriptorArsenic methyltransferase, S-ADENOSYLMETHIONINE (2 entities in total)
Functional Keywordsrossmann fold, arsenic methyltransferase, transferase
Biological sourceCyanidioschyzon sp. 5508
Total number of polymer chains1
Total formula weight42711.17
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: 2023-09-13)
Primary citationAjees, 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: 22712827
DOI: 10.1021/bi3004632
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.75 Å)
Structure validation

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