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Publication Abstract from PubMed

The Mycobacterium tuberculosis Rv2258c protein is an S-adenosyl-L-methionine (SAM)-dependent methyltransferase (MTase). Here, we have determined its crystal structure in three forms: a ligand-unbound form, a binary complex with sinefungin (SFG), and a binary complex with S-adenosyl-L-homocysteine (SAH). The monomer structure of Rv2258c consists of two domains which are linked by a long alpha-helix. The N-terminal domain is essential for dimerization and the C-terminal domain has the Class I MTase fold. Rv2258c forms a homodimer in the crystal, with the N-terminal domains facing each other. It also exists as a homodimer in solution. A DALI structural similarity search with Rv2258c reveals that the overall structure of Rv2258c is very similar to small-molecule SAM-dependent MTases. Rv2258c interacts with the bound SFG (or SAH) in an extended conformation maintained by a network of hydrogen bonds and stacking interactions. Rv2258c has a relatively large hydrophobic cavity for binding of the methyl-accepting substrate, suggesting that bulky nonpolar molecules with aromatic rings might be targeted for methylation by Rv2258c in M. tuberculosis. However, the ligand-binding specificity and the biological role of Rv2258c remain to be elucidated due to high variability of the amino acid residues defining the substrate-binding site.

Crystal structure of Rv2258c from Mycobacterium tuberculosis H37Rv, an S-adenosyl-l-methionine-dependent methyltransferase.,Im HN, Kim HS, An DR, Jang JY, Kim J, Yoon HJ, Yang JK, Suh SW J Struct Biol. 2016 Mar;193(3):172-80. doi: 10.1016/j.jsb.2016.01.002. Epub 2016 , Jan 6. PMID:26772148^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.