3DUW

Crystal Structural Analysis of the O-methyltransferase from Bacillus cereus in complex SAH

3DUW の概要

• エントリーDOI: 10.2210/pdb3duw/pdb
• 関連するPDBエントリー: 3DUL
• 分子名称: O-methyltransferase, putative, S-ADENOSYL-L-HOMOCYSTEINE (3 entities in total)
• 機能のキーワード: alternating of alpha and beta with complex sah, methyltransferase, transferase
• 由来する生物種: Bacillus cereus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 50311.54

構造登録者

Cho, J.-H.,Rhee, S. (登録日: 2008-07-18, 公開日: 2008-08-05, 最終更新日: 2024-11-20)

主引用文献

Cho, J.-H.,Park, Y.,Ahn, J.-H.,Lim, Y.,Rhee, S.
Structural and functional insights into O-methyltransferase from Bacillus cereus
J.Mol.Biol., 382:987-997, 2008

PubMed Abstract: The specific substrates, mechanisms, and structures of the bacterial O-methyltransferases (OMTs) are not as well characterized as those of other OMTs. Recent studies have suggested that bacterial OMTs catalyze regiospecific reactions that might be used to produce novel compounds. In this study, we investigated the structural and functional features of an OMT from Bacillus cereus (BcOMT2). This enzyme catalyzes the O-methylation of flavonoids in vitro in an S-adenosylmethionine-dependent and regiospecific manner. We solved the crystal structures of the BcOMT2 apoenzyme and the BcOMT2-S-adenosylhomocysteine (SAH) co-complex at resolutions of 1.8 and 1.2 A, respectively. These structures reveal that the overall structure of dimeric BcOMT2 is similar to that of the canonical OMT but that BcOMT2 also has a unique N-terminal helical region that is responsible for dimerization. The binding of SAH causes both local and remote conformational changes in the dimer interface that stabilize the dimerization of BcOMT2. SAH binding also causes ordering of residues Glu171 to Gly186, which are disordered in the apoenzyme structure and are known determinants of substrate specificity, and thus contributes to formation of the substrate binding pocket. Our structural analysis indicated a resemblance between the active site of BcOMT2 and that of metal-dependent OMTs. Using mutational analysis, we confirmed that BcOMT2 is a Mg(2+)-dependent OMT. These results provide structural and functional insights into the dimerization mechanism and substrate specificity of BcOMT2.

PubMed: 18706426
DOI: 10.1016/j.jmb.2008.07.080

実験手法

X-RAY DIFFRACTION (1.2 Å)