4a2n

Crystal Structure of Ma-ICMT

spinqualitylabelsall models 4a2n, resolution 3.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4a2n is a 1 chain structure with sequence from Methanosarcina acetivorans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CDL, PLM, SAH Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The posttranslational modification of C-terminal CAAX motifs in proteins such as Ras, most Rho GTPases, and G protein gamma subunits, plays an essential role in determining their subcellular localization and correct biological function. An integral membrane methyltransferase, isoprenylcysteine carboxyl methyltransferase (ICMT), catalyzes the final step of CAAX processing after prenylation of the cysteine residue and endoproteolysis of the -AAX motif. We have determined the crystal structure of a prokaryotic ICMT ortholog, revealing a markedly different architecture from conventional methyltransferases that utilize S-adenosyl-L-methionine (SAM) as a cofactor. ICMT comprises a core of five transmembrane alpha helices and a cofactor-binding pocket enclosed within a highly conserved C-terminal catalytic subdomain. A tunnel linking the reactive methyl group of SAM to the inner membrane provides access for the prenyl lipid substrate. This study explains how an integral membrane methyltransferase achieves recognition of both a hydrophilic cofactor and a lipophilic prenyl group attached to a polar protein substrate. Mechanism of Isoprenylcysteine Carboxyl Methylation from the Crystal Structure of the Integral Membrane Methyltransferase ICMT.,Yang J, Kulkarni K, Manolaridis I, Zhang Z, Dodd RB, Mas-Droux C, Barford D Mol Cell. 2011 Dec 23;44(6):997-1004. PMID:22195972 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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