4A2N

Crystal Structure of Ma-ICMT

4A2N の概要

• エントリーDOI: 10.2210/pdb4a2n/pdb
• 分子名称: ISOPRENYLCYSTEINE CARBOXYL METHYLTRANSFERASE, S-ADENOSYL-L-HOMOCYSTEINE, PALMITIC ACID, ... (4 entities in total)
• 機能のキーワード: transferase, membrane protein, ras and rho gtpases signalling
• 由来する生物種: METHANOSARCINA ACETIVORANS
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 24944.13

構造登録者

Yang, J.,Kulkarni, K.,Manolaridis, I.,Zhang, Z.,Dodd, R.B.,Mas-Droux, C.,Barford, D. (登録日: 2011-09-27, 公開日: 2012-01-11, 最終更新日: 2025-12-10)

主引用文献

Yang, J.,Kulkarni, K.,Manolaridis, I.,Zhang, Z.,Dodd, R.B.,Mas-Droux, C.,Barford, D.
Mechanism of Isoprenylcysteine Carboxyl Methylation from the Crystal Structure of the Integral Membrane Methyltransferase Icmt.
Mol.Cell, 44:997-, 2011

PubMed Abstract: The posttranslational modification of C-terminal CAAX motifs in proteins such as Ras, most Rho GTPases, and G protein γ 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 α 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.

PubMed: 22195972
DOI: 10.1016/J.MOLCEL.2011.10.020

実験手法

X-RAY DIFFRACTION (3.4 Å)