9GAB

Structure and catalytic mechanism of SAM-AMP lyase in Clostridium botulinum CorA-associated type III CRISPR system

これはPDB形式変換不可エントリーです。

9GAB の概要

• エントリーDOI: 10.2210/pdb9gab/pdb
• 分子名称: SAM-AMP Lyase, [(2~{R},3~{S},4~{R},5~{R})-5-(6-aminopurin-9-yl)-3,4-bis(oxidanyl)oxolan-2-yl]methyl [(2~{S},3~{S},4~{R},5~{R})-5-(6-aminopurin-9-yl)-2-(methylsulfanylmethyl)-4-oxidanyl-oxolan-3-yl] hydrogen phosphate, (4S)-2-METHYL-2,4-PENTANEDIOL, ... (4 entities in total)
• 機能のキーワード: type iii crispr, lyase
• 由来する生物種: Clostridium botulinum
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 93298.52

構造登録者

McMahon, S.A.,Chi, H.,Gloster, T.M.,White, M.F.,Graham, S. (登録日: 2024-07-26, 公開日: 2025-07-02, 最終更新日: 2025-07-23)

主引用文献

Chi, H.,McMahon, S.,Daniel-Pedersen, L.,Graham, S.,Gloster, T.M.,White, M.F.
SAM-AMP lyases in type III CRISPR defence.
Nucleic Acids Res., 53:-, 2025

PubMed Abstract: Type III CRISPR systems detect non-self RNA and activate the enzymatic Cas10 subunit, which generates nucleotide second messengers for activation of ancillary effectors. Although most signal via cyclic oligoadenylate, an alternative class of signalling molecule SAM-AMP, formed by conjugating ATP and S-adenosylmethionine, was described recently. SAM-AMP activates a trans-membrane effector of the CorA magnesium transporter family to provide anti-phage defence. Intriguingly, immunity also requires SAM-AMP degradation by means of a specialized CRISPR-encoded NrN family phosphodiesterase in Bacteroides fragilis. In Clostridium botulinum, the nrn gene is replaced by a gene encoding a SAM-AMP lyase. Here, we investigate the structure and activity of C. botulinum SAM-AMP lyase, which can substitute for the nrn gene to provide CorA-mediated immunity in Escherichia coli. The structure of SAM-AMP lyase bound to its reaction product 5'-methylthioadenosine-AMP reveals key details of substrate binding and turnover by this PII superfamily protein. Bioinformatic analysis revealed a phage-encoded SAM-AMP lyase that degrades SAM-AMP efficiently in vitro, consistent with an anti-CRISPR function.

PubMed: 40650973
DOI: 10.1093/nar/gkaf655

実験手法

X-RAY DIFFRACTION (1.65 Å)