Annotations: 1UB4

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1ub4a_	All beta proteins	SH3-like barrel	Cell growth inhibitor/plasmid maintenance toxic component	Kid/PemK	MazF protein	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
B	d1ub4b_	All beta proteins	SH3-like barrel	Cell growth inhibitor/plasmid maintenance toxic component	Kid/PemK	MazF protein	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)
C	d1ub4c_	All beta proteins	Double-split beta-barrel	AbrB/MazE/MraZ-like	Kis/PemI addiction antidote	MazE	(Escherichia coli ) [TaxId: 562 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2 Family	Kid/PemK	8022515	4002619	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Cell growth inhibitor/plasmid maintenance toxic component	8034895	3000352	SCOP2 (2022-06-29)
B	SCOP2B Superfamily	Cell growth inhibitor/plasmid maintenance toxic component	8034895	3000352	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	AbrB/MazE/MraZ-like	8032898	3000181	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	PemK_toxin	e1ub4A1	A: beta barrels	X: SH3	H: SH3	T: SH3	F: PemK_toxin	ECOD (1.6)
B	PemK_toxin	e1ub4B1	A: beta barrels	X: SH3	H: SH3	T: SH3	F: PemK_toxin	ECOD (1.6)
C	MazE_antitoxin	e1ub4C1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: AbrB	F: MazE_antitoxin	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	2.30.30.110	Mainly Beta	Roll	SH3 type barrels.		CATH (4.3.0)
B	2.30.30.110	Mainly Beta	Roll	SH3 type barrels.		CATH (4.3.0)
C	2.10.260.10	Mainly Beta	Ribbon	Pemi-like Protein 1	Chain: D	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF02452	PemK-like, MazF-like toxin of type II toxin-antitoxin system (PemK_toxin)	PemK-like, MazF-like toxin of type II toxin-antitoxin system	PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of ...	PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of different toxins, such as MazF, Kid, PemK, ChpA, ChpB and ChpAK.	Domain
C	PF04014	Antidote-toxin recognition MazE, bacterial antitoxin (MazE_antitoxin)	Antidote-toxin recognition MazE, bacterial antitoxin	AbrB-like is a family of small proteins that operate in conjunction with a cognate toxin molecule. The commonly attributed role of toxin-antitoxin systems is to maintain low-copy number plasmids from one generation to the next. Such gene-pairs are al ...	AbrB-like is a family of small proteins that operate in conjunction with a cognate toxin molecule. The commonly attributed role of toxin-antitoxin systems is to maintain low-copy number plasmids from one generation to the next. Such gene-pairs are also found on chromosomes and to be associated with a number of biological functions such as: reduction of protein synthesis, gene regulation and retardation of cell growth under nutritional stress [1]. This family includes proteins from a number of different pairings, eg MazE, AbrB, VapB [2], PhoU, PemI-like and SpoVT. MazE is the antidote to the toxin MazF of E. coli. MazE-MazF in E. coli is a regulated prokaryotic chromosomal addiction module. MazE antidote is degraded by the ClpPA protease of the bacterial proteasome. MazE-MazF is thought to play a role in programmed cell death when cells suffer nutrient deprivation [3], and MazE-MazF modules have also been implicated in the bacteriostatic effects of other addiction modules [3].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	MazF protein	DNA binding binding organic cyclic compound binding nucleic acid binding identical protein binding protein binding protein homodimerization activity protein dimerization activity protein-containing complex binding endonuclease activity nuclease activity hydrolase activity, acting on ester bonds catalytic activity, acting on RNA RNA endonuclease activity DNA binding binding organic cyclic compound binding nucleic acid binding identical protein binding protein binding protein homodimerization activity protein dimerization activity protein-containing complex binding endonuclease activity nuclease activity hydrolase activity, acting on ester bonds catalytic activity, acting on RNA RNA endonuclease activity catalytic activity, acting on a nucleic acid RNA nuclease activity hydrolase activity catalytic activity molecular function activator activity molecular function regulator activity RNA binding	regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process nucleobase-containing compound metabolic process RNA biosynthetic process nucleic acid biosynthetic process DNA-templated transcription regulation of RNA metabolic process organic substance metabolic process organic substance biosynthetic process regulation of nucleobase-containing compound metabolic process regulation of RNA biosynthetic process regulation of biosynthetic process regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process nucleobase-containing compound metabolic process RNA biosynthetic process nucleic acid biosynthetic process DNA-templated transcription regulation of RNA metabolic process organic substance metabolic process organic substance biosynthetic process regulation of nucleobase-containing compound metabolic process regulation of RNA biosynthetic process regulation of biosynthetic process regulation of biological process cellular metabolic process biological regulation primary metabolic process regulation of cellular metabolic process regulation of macromolecule metabolic process nucleobase-containing compound biosynthetic process gene expression macromolecule biosynthetic process nucleic acid metabolic process regulation of cellular biosynthetic process organic cyclic compound metabolic process regulation of gene expression biosynthetic process organic cyclic compound biosynthetic process metabolic process regulation of macromolecule biosynthetic process cellular process regulation of DNA-templated transcription macromolecule metabolic process regulation of metabolic process catabolic process negative regulation of biological process negative regulation of cellular metabolic process macromolecule catabolic process negative regulation of cellular process RNA catabolic process negative regulation of macromolecule metabolic process mRNA catabolic process negative regulation of metabolic process mRNA metabolic process negative regulation of cellular biosynthetic process organic cyclic compound catabolic process nucleobase-containing compound catabolic process negative regulation of gene expression negative regulation of biosynthetic process negative regulation of macromolecule biosynthetic process nucleic acid catabolic process organic substance catabolic process positive regulation of programmed cell death positive regulation of biological process regulation of programmed cell death cell death programmed cell death positive regulation of cellular process response to stimulus signaling quorum sensing cell-cell signaling detection of cell density detection of biotic stimulus response to biotic stimulus cell communication detection of stimulus regulation of growth growth organonitrogen compound biosynthetic process post-transcriptional regulation of gene expression protein metabolic process organonitrogen compound metabolic process regulation of protein metabolic process translation regulation of translation rRNA catabolic process ncRNA metabolic process rRNA metabolic process regulation of cellular component organization negative regulation of cell growth regulation of cell growth cell growth cellular component organization negative regulation of growth cellular component organization or biogenesis biological process involved in interspecies interaction between organisms response to other organism defense response defense response to symbiont response to external stimulus defense response to virus defense response to other organism response to stress response to external biotic stimulus response to virus cell aggregation biofilm formation biological process involved in intraspecies interaction between organisms single-species biofilm formation aggregation of unicellular organisms	protein-containing complex transcription regulator complex toxin-antitoxin complex transcription repressor complex
C	MazE protein	DNA binding double-stranded DNA binding binding organic cyclic compound binding nucleic acid binding identical protein binding protein binding protein homodimerization activity protein dimerization activity protein-containing complex binding molecular sequestering activity toxin sequestering activity	regulation of growth regulation of biological process biological regulation growth regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process nucleobase-containing compound metabolic process RNA biosynthetic process nucleic acid biosynthetic process DNA-templated transcription regulation of RNA metabolic process organic substance metabolic process regulation of growth regulation of biological process biological regulation growth regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process nucleobase-containing compound metabolic process RNA biosynthetic process nucleic acid biosynthetic process DNA-templated transcription regulation of RNA metabolic process organic substance metabolic process organic substance biosynthetic process regulation of nucleobase-containing compound metabolic process regulation of RNA biosynthetic process regulation of biosynthetic process cellular metabolic process primary metabolic process regulation of cellular metabolic process regulation of macromolecule metabolic process nucleobase-containing compound biosynthetic process gene expression macromolecule biosynthetic process nucleic acid metabolic process regulation of cellular biosynthetic process organic cyclic compound metabolic process regulation of gene expression biosynthetic process organic cyclic compound biosynthetic process metabolic process regulation of macromolecule biosynthetic process cellular process regulation of DNA-templated transcription macromolecule metabolic process regulation of metabolic process cell aggregation biofilm formation biological process involved in intraspecies interaction between organisms single-species biofilm formation aggregation of unicellular organisms	protein-containing complex transcription regulator complex toxin-antitoxin complex transcription repressor complex

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR011067	Plasmid maintenance toxin/Cell growth inhibitor	Homologous Superfamily
A, B	IPR003477	mRNA interferase PemK-like	Family
C	IPR039052	Antitoxin PemI-like	Family
C	IPR037914	SpoVT-AbrB domain superfamily	Homologous Superfamily
C	IPR007159	SpoVT-AbrB domain	Domain

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.