1nbi | pdb_00001nbi

Structure of R175K mutated glycine N-methyltransferase complexed with S-adenosylmethionine, R175K:SAM.

spinqualitylabelsall models 1nbi, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nbi is a 4 chain structure with sequence from Buffalo rat. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SAM Gene: GNMT (Buffalo rat) Activity: Glycine N-methyltransferase, with EC number 2.1.1.20 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [GNMT_RAT] Catalyzes the methylation of glycine by using S-adenosylmethionine (AdoMet) to form N-methylglycine (sarcosine) with the concomitant production of S-adenosylhomocysteine (AdoHcy). Possible crucial role in the regulation of tissue concentration of AdoMet and of metabolism of methionine. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Methyltransfer reactions are some of the most important reactions in biological systems. Glycine N-methyltransferase (GNMT) catalyzes the S-adenosyl-l-methionine- (SAM-) dependent methylation of glycine to form sarcosine. Unlike most SAM-dependent methyltransferases, GNMT has a relatively high value and is weakly inhibited by the product S-adenosyl-l-homocysteine (SAH). The major role of GNMT is believed to be the regulation of the cellular SAM/SAH ratio, which is thought to play a key role in SAM-dependent methyltransfer reactions. Crystal structures of GNMT complexed with SAM and acetate (a potent competitive inhibitor of Gly) and the R175K mutated enzyme complexed with SAM were determined at 2.8 and 3.0 A resolutions, respectively. With these crystal structures and the previously determined structures of substrate-free enzyme, a catalytic mechanism has been proposed. Structural changes occur in the transitions from the substrate-free to the binary complex and from the binary to the ternary complex. In the ternary complex stage, an alpha-helix in the N-terminus undergoes a major conformational change. As a result, the bound SAM is firmly connected to protein and a "Gly pocket" is created near the bound SAM. The second substrate Gly binds to Arg175 and is brought into the Gly pocket. Five hydrogen bonds connect the Gly in the proximity of the bound SAM and orient the lone pair orbital on the amino nitrogen (N) of Gly toward the donor methyl group (C(E)) of SAM. Thermal motion of the enzyme leads to a collision of the N and C(E) so that a S(N)2 methyltransfer reaction occurs. The proposed mechanism is supported by mutagenesis studies. Catalytic mechanism of glycine N-methyltransferase.,Takata Y, Huang Y, Komoto J, Yamada T, Konishi K, Ogawa H, Gomi T, Fujioka M, Takusagawa F Biochemistry. 2003 Jul 22;42(28):8394-402. PMID:12859184 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA