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Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases

หน่วยงาน Nanyang Technological University, Singapore

รายละเอียด

ชื่อเรื่อง : Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases
นักวิจัย : Kumar, Manoj , Hirao, Hajime , Kozlowski, Pawel M.
คำค้น : DRNTU::Science::Chemistry::Biochemistry
หน่วยงาน : Nanyang Technological University, Singapore
ผู้ร่วมงาน : -
ปีพิมพ์ : 2555
อ้างอิง : Kumar, M., Hirao, H., & Kozlowski, P. M. (2012). Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases. JBIC journal of biological inorganic chemistry, 17(7), 1107-1121. , http://hdl.handle.net/10220/17520 , http://dx.doi.org/10.1007/s00775-012-0924-x
ที่มา : -
ความเชี่ยวชาญ : -
ความสัมพันธ์ : JBIC journal of biological inorganic chemistry
ขอบเขตของเนื้อหา : -
บทคัดย่อ/คำอธิบาย :

A detailed computational analysis employing density functional theory (DFT), atoms in molecules, and quantum mechanics/molecular mechanics (QM/MM) tools has been performed to investigate the primary coordination environment of cob(I)alamin (Co+Cbx), which is a ubiquitous B12 intermediate in methyltransferases and ATP:corrinoid adenosyltransferases. The DFT calculations suggest that the simplified (Co+Cbl) as well as the complete (Co+Cbi) complexes can adapt to the square pyramidal or octahedral coordination geometry owing to the unconventional H-bonding between the Co+ ion and its axial ligands. These Co+–H bonds contain appreciable amounts of electrostatic, charge transfer, long-range correlation, and dispersion components. The computed reduction potentials of the Co2+/Co+ couple imply that the Co+–H(H2O) interaction causes a greater anodic shift [5–98 mV vs. the normal hydrogen electrode (NHE) in chloroform solvent] than the analogous Co+–H(imidazole) interaction (1 mV vs. NHE) in the reduction potential of the Co2+/Co+ couple. This may explain why a β-axial H2O ligand has specifically been found in the active sites of certain methyltransferases. The QM/MM analysis of methionine synthase bound Co+Cbx (Protein Data Bank ID 1BMT, resolution 3.0 Å) indicates that the enzyme-bound Co+Cbx can also form a Co+–H bond, but can only exist in square pyramidal form because of the steric constraints imposed by the cellular environment. The present calculations thus support a recently proposed alternate mechanism for the enzyme-bound Co2+/Co+ reduction that involves the conversion of square pyramidal Co2+Cbx into square pyramidal Co+Cbx (Kumar and Kozlowski in Angew. Chem. Int. Ed. 50:8702–8705, 2011).

บรรณานุกรม :
Kumar, Manoj , Hirao, Hajime , Kozlowski, Pawel M. . (2555). Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases.
    กรุงเทพมหานคร : Nanyang Technological University, Singapore.
Kumar, Manoj , Hirao, Hajime , Kozlowski, Pawel M. . 2555. "Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases".
    กรุงเทพมหานคร : Nanyang Technological University, Singapore.
Kumar, Manoj , Hirao, Hajime , Kozlowski, Pawel M. . "Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases."
    กรุงเทพมหานคร : Nanyang Technological University, Singapore, 2555. Print.
Kumar, Manoj , Hirao, Hajime , Kozlowski, Pawel M. . Co+–H interaction inspired alternate coordination geometries of biologically important cob(I)alamin : possible structural and mechanistic consequences for methyltransferases. กรุงเทพมหานคร : Nanyang Technological University, Singapore; 2555.