PMID:41741653

A membrane-bound nuclease directly cleaves phage DNA during genome injection

SNIPE is a membrane-bound nuclease that directly cleaves phage DNA during genome injection, providing direct defence against bacteriophage

"we demonstrate that SNIPE directly cleaves phage DNA during genome injection"
SNIPE constitutively localizes to the bacterial cell membrane

"we characterize SNIPE, an anti-bacteriophage defence system that constitutively localizes to the bacterial cell membrane in Escherichia coli to block phage"
SNIPE pre-associates with host proteins for lambda genome entry and with the tape measure protein during genome injection

"SNIPE associates with host proteins essential for λ genome entry and with the λ tape measure protein, which facilitates λ genome injection across the inner membrane"
Radiolabelled phage DNA tracking demonstrates SNIPE cleaves DNA during injection

"Using radiolabelled phage DNA and time-lapse microscopy to track phage genomes, we demonstrate that SNIPE directly cleaves phage DNA during genome injection"
SNIPE provides ManYZ-independent defence against siphoviruses via direct TMP interaction

"SNIPE also defends against diverse siphoviruses, probably through direct interactions with their tape measure proteins"
SNIPE is a widespread defence system representing a novel self/non-self discrimination strategy

"SNIPE as a widespread bacterial defence system that exploits the spatial organization of phage genome injection to specifically target viral DNA, representing a previously unknown strategy for distinguishing self from non-self in prokaryotic immune systems"

PMID:36123438

A functional selection reveals previously undetected anti-phage defence systems in the E. coli pangenome

SNIPE (originally PD-lambda-1) was identified in a functional metagenomic screen of 71 diverse E. coli strains as a novel anti-phage defence system

"Our results unveil 21 conserved defence systems, none of which were previously detected as enriched in defence islands"
SNIPE is a membrane-anchored protein with DUF4041 and a GIY-YIG nuclease domain

"a putative membrane-anchored protein with a central coiled-coil domain (DUF4041) and a C-terminal DNA binding/cleavage domain"
Defence systems including SNIPE are carried primarily by prophages and mobile genetic elements

"intact prophages and mobile genetic elements are primary reservoirs and distributors of defence systems in E. coli"

file:ECOLX/SNIPE/SNIPE-deep-research-falcon.md

Deep research on SNIPE/DUF4041 domain-containing protein (falcon)

T5orf172/MUG113 (PF13455) is a GIY-YIG endonuclease subfamily; MUG113 profile is highly related to T5orf172, placing SNIPE's nuclease domain in the GIY-YIG HEG space

"T5orf172 is a subfamily of GIY-YIG endonucleases ... the two profiles [T5orf172 and MUG113] are highly related"
T5orf172-family proteins have modular architecture with variable DNA-binding modules determining target specificity, paired with a conserved nuclease domain

"a nuclease domain paired with variable DNA-binding modules that determine target specificity"

file:ECOLX/SNIPE/SNIPE-bioinformatics/RESULTS.md

SNIPE Architecture-Aware Feature Analysis (InterPro)

An InterPro rule for SNIPE should combine the SNIPE-associated IPR025280 domain with a GIY-YIG catalytic partner and membrane-targeting features rather than key only on the accessory domain.

"IPR025280 + (PF13455 OR IPR018306/PF10544) + (N-term TM/signal peptide OR membrane-associated accessory domain such as IPR007829/IPR039519; optional lower-confidence IPR018929)."