file:STRTR/cas10/cas10-record-evidence.yaml

Compact archived record and sequence evidence for A0A0A7HFE1

UniProtKB:A0A0A7HFE1

UniProtKB entry for Streptococcus thermophilus Cas10/Csm1 (A0A0A7HFE1)

The N-terminal HD domain has ssDNase activity (ECO:0000269|PubMed:27105119) and the C-terminal GGDEF domain has the cOA synthesis activity (ECO:0000269|PubMed:28663439).
The two catalytic centres are genetically separable: the D16A substitution dramatically decreases ssDNase activity but leaves wild-type cOA synthesis, and the D575-D576 to AA substitution leaves wild-type ssDNase activity but abolishes cOA synthesis.
Experimentally determined catalytic activity 6 ATP = cyclic hexaadenylate + 6 diphosphate (Rhea:RHEA:58276), with cA3 to cA6 produced and cA6 the active species; synthesis requires a free 3'-OH ribose moiety and accepts 2'dATP or 3'dATP but no other nucleotides.
Degradation of ssDNA requires Mn(2+), Co(2+) or Ni(2+) and is not activated by Mg(2+), Ca(2+) or Zn(2+); formation of cOA requires Mn(2+), Co(2+) or Zn(2+). ssDNase activity is inhibited by EDTA.
Part of the Csm effector complex that includes at least Cas10(1), Csm2(3), Csm3(5), Csm4(1), Csm5(1) and mature crRNA; Cas10 and Csm4 cap one end of the Csm3 filament.

PMID:28663439

A cyclic oligonucleotide signaling pathway in type III CRISPR-Cas systems.

Target RNA binding by the Streptococcus thermophilus Csm effector complex triggers Cas10 to synthesise cyclic oligoadenylates through its Palm domains.

"target RNA binding by the Csm effector complex of Streptococcus thermophilus triggers Cas10 to synthesize cyclic oligoadenylates"
Cas10 contains an HD nuclease domain responsible for DNA degradation and two Palm domains.

"The Cas10 subunit of the complex contains an HD nuclease domain that is responsible for DNA degradation and two Palm domains with elusive functions."
The cyclic oligoadenylates act as signalling molecules that bind Csm6 and switch on its nonspecific RNA degradation, coordinating the components of the system to prevent phage propagation.

"Acting as signaling molecules, cyclic oligoadenylates bind Csm6 to activate its nonspecific RNA degradation."

PMID:27105119

Spatiotemporal Control of Type III-A CRISPR-Cas Immunity: Coupling DNA Degradation with the Target RNA Recognition.

Base-pairing between the crRNA and a target RNA activates single-stranded DNA degradation by the Streptococcus thermophilus Csm complex.

"base-pairing between crRNA and target RNA activates single-stranded DNA (ssDNA) degradation by StCsm"
The single-stranded DNase activity resides in the HD domain of Cas10.

"ssDNase activity is confined to the HD-domain of Cas10"
Cleavage of the target RNA by Csm3 suppresses the Cas10 DNase, giving the DNA degradation a defined temporal window.

"target RNA cleavage by the Csm3 RNase suppresses Cas10 DNase activity, ensuring temporal control of DNA degradation"
Pairing of the crRNA 5' handle with the 3' flank of the target RNA inhibits the Cas10 ssDNase, preventing self-targeting.

"base-pairing between crRNA 5'-handle and target RNA 3'-flanking sequence inhibits Cas10 ssDNase to prevent self-targeting"
crRNA-guided binding to an emerging transcript recruits the Cas10 DNase to actively transcribed invader DNA, sparing host DNA.

"crRNA-guided StCsm binding to the emerging transcript recruits Cas10 DNase to the actively transcribed phage DNA, resulting in degradation of both the transcript and phage DNA, but not the host DNA"

PMID:25458845

Programmable RNA shredding by the type III-A CRISPR-Cas system of Streptococcus thermophilus.

Two Csm complexes of different stoichiometry were purified from a heterologous host, associated with 40 and 72 nucleotide crRNA species.

"When expressed in Escherichia coli, two complexes of different stoichiometry copurified with 40 and 72 nt crRNA species, respectively."
The complex cleaves target RNA at 6 nucleotide intervals, and the Csm3 subunit is the endoribonuclease responsible.

"The Csm3 protein, present in multiple copies in both Csm complexes, acts as endoribonuclease."
The system restricts MS2 RNA phage in a heterologous host, and in that assay the restriction depends on the Csm3 nuclease rather than on Cas10.

"In the heterologous E. coli host, StCsm restricts MS2 RNA phage in a Csm3 nuclease-dependent manner."

PMID:28722012

Type III CRISPR-Cas systems produce cyclic oligoadenylate second messengers.

Independent demonstration that the Cas10 subunit converts ATP into a cyclic oligoadenylate on target RNA binding, and that the product activates Csm6 through its CARF domain.

"Upon target RNA binding by the interference complex, its Cas10 subunit converts ATP into a cyclic oligoadenylate product, which allosterically activates Csm6 by binding to its CRISPR-associated Rossmann fold (CARF) domain."