6V63

SETD3 WT in Complex with an Actin Peptide with His73 Replaced with Glutamine

6V63 の概要

• エントリーDOI: 10.2210/pdb6v63/pdb
• 分子名称: Actin, cytoplasmic 1, Actin-histidine N-methyltransferase, GLYCEROL, ... (7 entities in total)
• 機能のキーワード: transferase, transferase-structural protein complex, transferase/structural protein
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 143935.32

構造登録者

Dai, S.,Horton, J.R.,Cheng, X. (登録日: 2019-12-04, 公開日: 2020-01-22, 最終更新日: 2023-10-11)

主引用文献

Dai, S.,Horton, J.R.,Wilkinson, A.W.,Gozani, O.,Zhang, X.,Cheng, X.
An engineered variant of SETD3 methyltransferase alters target specificity from histidine to lysine methylation.
J.Biol.Chem., 295:2582-2589, 2020

PubMed Abstract: Most characterized SET domain (SETD) proteins are protein lysine methyltransferases, but SETD3 was recently demonstrated to be a protein ( actin) histidine-N methyltransferase. Human SETD3 shares a high structural homology with two known protein lysine methyltransferases-human SETD6 and the plant LSMT-but differs in the residues constituting the active site. In the SETD3 active site, Asn engages in a unique hydrogen-bonding interaction with the target histidine of actin that likely contributes to its >1300-fold greater catalytic efficiency (/ ) on histidine than on lysine. Here, we engineered active-site variants to switch the SETD3 target specificity from histidine to lysine. Substitution of Asn with phenylalanine (N255F), together with substitution of Trp with alanine (W273A), generated an active site mimicking that of known lysine methyltransferases. The doubly substituted SETD3 variant exhibited a 13-fold preference for lysine over histidine. We show, by means of X-ray crystallography, that the two target nitrogen atoms-the N atom of histidine and the terminal ϵ-amino nitrogen of lysine-occupy the same position and point toward and are within a short distance of the incoming methyl group of SAM for a direct methyl transfer during catalysis. In contrast, SETD3 and its Asn substituted derivatives did not methylate glutamine (another potentially methylated amino acid). However, the glutamine-containing peptide competed with the substrate peptide, and glutamine bound in the active site, but too far away from SAM to be methylated. Our results provide insight into the structural parameters defining the target amino acid specificity of SET enzymes.

PubMed: 31911441
DOI: 10.1074/jbc.RA119.012319

実験手法

X-RAY DIFFRACTION (2.02 Å)