Annotations: 3ISM

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	Endonuclease_NS	e3ismA1	A: few secondary structure elements	X: His-Me finger endonucleases (From Homology)	H: His-Me finger endonucleases	T: His-Me finger endonucleases	F: Endonuclease_NS	ECOD (1.6)
B	Endonuclease_NS	e3ismB1	A: few secondary structure elements	X: His-Me finger endonucleases (From Homology)	H: His-Me finger endonucleases	T: His-Me finger endonucleases	F: Endonuclease_NS	ECOD (1.6)
C	Ku_PK_bind	e3ismC1	A: alpha superhelices	X: Repetitive alpha hairpins	H: C-terminal domain of Ku80 (From Topology)	T: C-terminal domain of Ku80	F: Ku_PK_bind	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.40.570.10	Alpha Beta	3-Layer(aba) Sandwich	Extracellular Endonuclease	Chain A	CATH (4.3.0)
B	3.40.570.10	Alpha Beta	3-Layer(aba) Sandwich	Extracellular Endonuclease	Chain A	CATH (4.3.0)
C	1.25.40.240	Mainly Alpha	Alpha Horseshoe	Serine Threonine Protein Phosphatase 5, Tetratricopeptide repeat	Ku, C-terminal domain	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF01223	DNA/RNA non-specific endonuclease (Endonuclease_NS)	DNA/RNA non-specific endonuclease		Domain
C	PF08785	Ku C terminal domain like (Ku_PK_bind)	Ku C terminal domain like	The non-homologous end joining (NHEJ) pathway is one method by which double stranded breaks in chromosomal DNA are repaired. Ku is a component of a multi-protein complex that is involved in the NHEJ. Ku has affinity for DNA ends and recruits the DNA ...	The non-homologous end joining (NHEJ) pathway is one method by which double stranded breaks in chromosomal DNA are repaired. Ku is a component of a multi-protein complex that is involved in the NHEJ. Ku has affinity for DNA ends and recruits the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). This domain is found at the C terminal of Ku which binds to DNA-PKcs [1].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	CG8862	binding nucleic acid binding DNA endonuclease activity endonuclease activity catalytic activity, acting on DNA nuclease activity hydrolase activity, acting on ester bonds catalytic activity, acting on a nucleic acid hydrolase activity catalytic activity DNA nuclease activity catalytic activity, acting on RNA RNA endonuclease activity RNA nuclease activity binding nucleic acid binding DNA endonuclease activity endonuclease activity catalytic activity, acting on DNA nuclease activity hydrolase activity, acting on ester bonds catalytic activity, acting on a nucleic acid hydrolase activity catalytic activity DNA nuclease activity catalytic activity, acting on RNA RNA endonuclease activity RNA nuclease activity cation binding ion binding metal ion binding small molecule binding	developmental process spermatid development spermatid differentiation sexual reproduction cellular developmental process spermatogenesis reproductive process multicellular organismal reproductive process cell development cellular process involved in reproduction in multicellular organism developmental process involved in reproduction gamete generation male gamete generation cell differentiation anatomical structure development developmental process spermatid development spermatid differentiation sexual reproduction cellular developmental process spermatogenesis reproductive process multicellular organismal reproductive process cell development cellular process involved in reproduction in multicellular organism developmental process involved in reproduction gamete generation male gamete generation cell differentiation anatomical structure development germ cell development cellular process cellular component organization mitochondrion distribution localization mitochondrion localization organelle organization organelle localization organelle inheritance mitochondrion inheritance cellular component organization or biogenesis cell death programmed cell death involved in cell development ectopic germ cell programmed cell death programmed cell death catabolic process primary metabolic process DNA metabolic process mitochondrial genome maintenance mitochondrial DNA catabolic process nucleic acid metabolic process macromolecule catabolic process nucleobase-containing compound catabolic process mitochondrial DNA metabolic process nucleobase-containing compound metabolic process DNA catabolic process nucleic acid catabolic process metabolic process macromolecule metabolic process mitochondrion organization apoptotic process sperm mitochondrion organization	membrane-bounded organelle intracellular organelle cellular anatomical structure intracellular anatomical structure mitochondrion organelle cytoplasm intracellular membrane-bounded organelle cytosol mitochondrial intermembrane space membrane-enclosed lumen intracellular organelle lumen organelle envelope lumen organelle envelope membrane-bounded organelle intracellular organelle cellular anatomical structure intracellular anatomical structure mitochondrion organelle cytoplasm intracellular membrane-bounded organelle cytosol mitochondrial intermembrane space membrane-enclosed lumen intracellular organelle lumen organelle envelope lumen organelle envelope organelle lumen mitochondrial envelope nucleus
C	CG4930	enzyme regulator activity molecular function inhibitor activity molecular function regulator activity nuclease inhibitor activity enzyme inhibitor activity ribonuclease inhibitor activity	cellular response to stimulus positive regulation of cell communication regulation of cellular process positive regulation of signal transduction response to stimulus signaling positive regulation of biological process regulation of signal transduction cell communication positive regulation of response to stimulus signal transduction positive regulation of cellular process regulation of biological process regulation of signaling cellular response to stimulus positive regulation of cell communication regulation of cellular process positive regulation of signal transduction response to stimulus signaling positive regulation of biological process regulation of signal transduction cell communication positive regulation of response to stimulus signal transduction positive regulation of cellular process regulation of biological process regulation of signaling cell surface receptor signaling pathway biological regulation Notch signaling pathway regulation of response to stimulus regulation of Notch signaling pathway regulation of cell communication cellular process positive regulation of Notch signaling pathway positive regulation of signaling	membrane-bounded organelle intracellular organelle cellular anatomical structure intracellular anatomical structure organelle nucleus intracellular membrane-bounded organelle

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR018524	DNA/RNA non-specific endonuclease, active site	Active Site
A, B	IPR044929	DNA/RNA non-specific endonuclease superfamily	Homologous Superfamily
A, B	IPR044925	His-Me finger superfamily	Homologous Superfamily
A, B	IPR040255	Non-specific endonuclease	Family
A, B	IPR001604	DNA/RNA non-specific endonuclease/pyrophosphatase/phosphodiesterase domain	Domain
A, B	IPR020821	ENPP1-3/EXOG-like, endonuclease/phosphodiesterase domain	Domain
C	IPR036494	Ku, C-terminal domain superfamily	Homologous Superfamily
C	IPR014893	Ku, C-terminal	Domain

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), 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 R01GM157729.