exonuclease activity / endonuclease activity / defense response to virus / RNA binding / ATP binding 類似検索 - 分子機能
: / CRISPR RNA silencing complex Cmr2 subunit, second helical domain / Csm4, C-terminal / CRISPR Csm4 C-terminal domain / CRISPR-associated protein Csm5 / CRISPR-associated protein, Csm2 Type III-A / Csm2 Type III-A / : / CRISPR-associated RAMP Csm3 / CRISPR type III-associated RAMP protein Csm4 ...: / CRISPR RNA silencing complex Cmr2 subunit, second helical domain / Csm4, C-terminal / CRISPR Csm4 C-terminal domain / CRISPR-associated protein Csm5 / CRISPR-associated protein, Csm2 Type III-A / Csm2 Type III-A / : / CRISPR-associated RAMP Csm3 / CRISPR type III-associated RAMP protein Csm4 / CRISPR system single-strand-specific deoxyribonuclease Cas10/Csm1 / Csm1, subunit domain B / Csm1 subunit domain B / : / Cas10/Cmr2, second palm domain / : / CRISPR type III-associated protein / RAMP superfamily / HD domain / GGDEF domain profile. / GGDEF domain / HD domain / Reverse transcriptase/Diguanylate cyclase domain 類似検索 - ドメイン・相同性
CRISPR system Cms endoribonuclease Csm3 / CRISPR system single-strand-specific deoxyribonuclease Cas10/Csm1 (subtype III-A) / CRISPR system Cms protein Csm4 / CRISPR system Cms protein Csm2 / CRISPR system Cms protein Csm5 類似検索 - 構成要素
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM099604
米国
引用
ジャーナル: Nucleic Acids Res / 年: 2024 タイトル: Molecular basis for cA6 synthesis by a type III-A CRISPR-Cas enzyme and its conversion to cA4 production. 著者: Hemant N Goswami / Fozieh Ahmadizadeh / Bing Wang / Doreen Addo-Yobo / Yu Zhao / A Carl Whittington / Huan He / Michael P Terns / Hong Li / 要旨: The type III-A (Csm) CRISPR-Cas systems are multi-subunit and multipronged prokaryotic enzymes in guarding the hosts against viral invaders. Beyond cleaving activator RNA transcripts, Csm confers ...The type III-A (Csm) CRISPR-Cas systems are multi-subunit and multipronged prokaryotic enzymes in guarding the hosts against viral invaders. Beyond cleaving activator RNA transcripts, Csm confers two additional activities: shredding single-stranded DNA and synthesizing cyclic oligoadenylates (cOAs) by the Cas10 subunit. Known Cas10 enzymes exhibit a fascinating diversity in cOA production. Three major forms-cA3, cA4 and cA6have been identified, each with the potential to trigger unique downstream effects. Whereas the mechanism for cOA-dependent activation is well characterized, the molecular basis for synthesizing different cOA isoforms remains unclear. Here, we present structural characterization of a cA6-producing Csm complex during its activation by an activator RNA. Analysis of the captured intermediates of cA6 synthesis suggests a 3'-to-5' nucleotidyl transferring process. Three primary adenine binding sites can be identified along the chain elongation path, including a unique tyrosine-threonine dyad found only in the cA6-producing Cas10. Consistently, disrupting the tyrosine-threonine dyad specifically impaired cA6 production while promoting cA4 production. These findings suggest that Cas10 utilizes a unique enzymatic mechanism for forming the phosphodiester bond and has evolved distinct strategies to regulate the cOA chain length.