Annotations: 4I2O

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	cNMP_binding	e4i2oA1	A: beta sandwiches	X: jelly-roll	H: Double-stranded beta-helix (From Topology)	T: Double-stranded beta-helix	F: cNMP_binding	ECOD (1.6)
A	HTH_Crp_2	e4i2oA2	A: alpha arrays	X: HTH	H: HTH	T: winged	F: HTH_Crp_2	ECOD (1.6)
B	cNMP_binding	e4i2oB3	A: beta sandwiches	X: jelly-roll	H: Double-stranded beta-helix (From Topology)	T: Double-stranded beta-helix	F: cNMP_binding	ECOD (1.6)
B	HTH_Crp_2	e4i2oB2	A: alpha arrays	X: HTH	H: HTH	T: winged	F: HTH_Crp_2	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	2.60.120.10	Mainly Beta	Sandwich	Jelly Rolls	Jelly Rolls	CATH (4.3.0)
A	1.10.10.10	Mainly Alpha	Orthogonal Bundle	Arc Repressor Mutant, subunit A	Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain	CATH (4.3.0)
B	2.60.120.10	Mainly Beta	Sandwich	Jelly Rolls	Jelly Rolls	CATH (4.3.0)
B	1.10.10.10	Mainly Alpha	Orthogonal Bundle	Arc Repressor Mutant, subunit A	Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF13545	Crp-like helix-turn-helix domain (HTH_Crp_2)	Crp-like helix-turn-helix domain	This family represents a crp-like helix-turn-helix domain that is likely to bind DNA.	Domain
A, B	PF00027	Cyclic nucleotide-binding domain (cNMP_binding)	Cyclic nucleotide-binding domain	This domain sensor domain can bind cAMP, cGMP, c-di-GMP, oxygen and 2-oxoglutarate (Matilla et. al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	FixK2 protein	DNA binding binding organic cyclic compound binding nucleic acid binding	regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process regulation of nitrogen compound 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 heterocycle metabolic process organic substance biosynthetic process nitrogen compound metabolic process regulation of cellular process cellular biosynthetic process RNA metabolic process regulation of primary metabolic process regulation of nitrogen compound 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 heterocycle metabolic process organic substance biosynthetic process nitrogen compound metabolic 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 cellular nitrogen compound metabolic process primary metabolic process regulation of cellular metabolic process regulation of macromolecule metabolic process nucleobase-containing compound biosynthetic process heterocycle 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 aromatic compound biosynthetic process organic cyclic compound biosynthetic process metabolic process cellular process regulation of macromolecule biosynthetic process regulation of DNA-templated transcription macromolecule metabolic process regulation of metabolic process cellular aromatic compound metabolic process	-
C [auth W]	Promoter of fixK2 direct target, fixN, upstream	-	-	-
D [auth X]	Promoter of fixK2 direct target, fixN, downstream	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR000595	Cyclic nucleotide-binding domain	Domain
A, B	IPR018490	Cyclic nucleotide-binding domain superfamily	Homologous Superfamily
A, B	IPR036388	Winged helix-like DNA-binding domain superfamily	Homologous Superfamily
A, B	IPR036390	Winged helix DNA-binding domain superfamily	Homologous Superfamily
A, B	IPR012318	Crp-type HTH domain	Domain
A, B	IPR014710	RmlC-like jelly roll fold	Homologous Superfamily

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.