6VT4

Naegleria gruberi RNA ligase R149A mutant apo

6VT4 の概要

• エントリーDOI: 10.2210/pdb6vt4/pdb
• 分子名称: RNA Ligase (2 entities in total)
• 機能のキーワード: rna repair, adenylyltransferase, ligase
• 由来する生物種: Naegleria gruberi (Amoeba)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 38575.72

構造登録者

Unciuleac, M.C.,Goldgur, Y.,Shuman, S. (登録日: 2020-02-12, 公開日: 2020-04-08, 最終更新日: 2023-10-11)

主引用文献

Unciuleac, M.C.,Goldgur, Y.,Shuman, S.
Caveat mutator: alanine substitutions for conserved amino acids in RNA ligase elicit unexpected rearrangements of the active site for lysine adenylylation.
Nucleic Acids Res., 48:5603-5615, 2020

PubMed Abstract: Naegleria gruberi RNA ligase (NgrRnl) exemplifies the Rnl5 family of adenosine triphosphate (ATP)-dependent polynucleotide ligases that seal 3'-OH RNA strands in the context of 3'-OH/5'-PO4 nicked duplexes. Like all classic ligases, NgrRnl forms a covalent lysyl-AMP intermediate. A two-metal mechanism of lysine adenylylation was established via a crystal structure of the NgrRnl•ATP•(Mn2+)2 Michaelis complex. Here we conducted an alanine scan of active site constituents that engage the ATP phosphates and the metal cofactors. We then determined crystal structures of ligase-defective NgrRnl-Ala mutants in complexes with ATP/Mn2+. The unexpected findings were that mutations K170A, E227A, K326A and R149A (none of which impacted overall enzyme structure) triggered adverse secondary changes in the active site entailing dislocations of the ATP phosphates, altered contacts to ATP, and variations in the numbers and positions of the metal ions that perverted the active sites into off-pathway states incompatible with lysine adenylylation. Each alanine mutation elicited a distinctive off-pathway distortion of the ligase active site. Our results illuminate a surprising plasticity of the ligase active site in its interactions with ATP and metals. More broadly, they underscore a valuable caveat when interpreting mutational data in the course of enzyme structure-function studies.

PubMed: 32315072
DOI: 10.1093/nar/gkaa238

実験手法

X-RAY DIFFRACTION (2.16 Å)