Annotations: 2W3F

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	GAF	e2w3fA1	A: a+b three layers	X: Profilin-like	H: sensor domains (From Topology)	T: sensor domains	F: GAF	ECOD (1.6)
B	GAF	e2w3fB1	A: a+b three layers	X: Profilin-like	H: sensor domains (From Topology)	T: sensor domains	F: GAF	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.30.450.40	Alpha Beta	2-Layer Sandwich	Beta-Lactamase	GAF domain	CATH (4.3.0)
B	3.30.450.40	Alpha Beta	2-Layer Sandwich	Beta-Lactamase	GAF domain	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF01590	GAF domain (GAF)	GAF domain	This domain is present in cGMP-specific phosphodiesterases, adenylyl and guanylyl cyclases, phytochromes, FhlA and NifA. Adenylyl and guanylyl cyclases catalyse ATP and GTP to the second messengers cAMP and cGMP, respectively, these products up-regul ...	This domain is present in cGMP-specific phosphodiesterases, adenylyl and guanylyl cyclases, phytochromes, FhlA and NifA. Adenylyl and guanylyl cyclases catalyse ATP and GTP to the second messengers cAMP and cGMP, respectively, these products up-regulating catalytic activity by binding to the regulatory GAF domain(s). The opposite hydrolysis reaction is catalysed by phosphodiesterase. cGMP-dependent 3',5'-cyclic phosphodiesterase catalyses the conversion of guanosine 3',5'-cyclic phosphate to guanosine 5'-phosphate. Here too, cGMP regulates catalytic activity by GAF-domain binding. Phytochromes are regulatory photoreceptors in plants and bacteria which exist in two thermally-stable states that are reversibly inter-convertible by light: the Pr state absorbs maximally in the red region of the spectrum, while the Pfr state absorbs maximally in the far-red region. This domain is also found in FhlA (formate hydrogen lyase transcriptional activator) and NifA, a transcriptional activator which is required for activation of most Nif operons which are directly involved in nitrogen fixation. NifA interacts with sigma-54. This domain can bind biliverdine and phycocyanobilin (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	TWO COMPONENT SENSOR HISTIDINE KINASE DEVS (GAF FAMILY PROTEIN)	cation binding magnesium ion binding ion binding binding metal ion binding small molecule binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding purine nucleotide binding organic cyclic compound binding anion binding cation binding magnesium ion binding ion binding binding metal ion binding small molecule binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding ribonucleotide binding nitric oxide binding oxygen binding molecular sensor activity molecular function regulator activity oxygen sensor activity catalytic activity, acting on a protein kinase activity protein kinase activity transferase activity catalytic activity phosphotransferase activity, alcohol group as acceptor transferase activity, transferring phosphorus-containing groups tetrapyrrole binding heme binding carbon monoxide binding phosphotransferase activity, nitrogenous group as acceptor protein histidine kinase activity phosphorelay sensor kinase activity protein binding protein dimerization activity	response to stimulus response to redox state response to decreased oxygen levels detection of hypoxia detection of stimulus response to hypoxia response to stress response to chemical detection of chemical stimulus response to oxygen levels response to abiotic stimulus detection of oxygen detection of redox state	cell periphery cellular anatomical structure plasma membrane membrane external encapsulating structure cell wall peptidoglycan-based cell wall intracellular anatomical structure cytoplasm

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR011712	Signal transduction histidine kinase, subgroup 3, dimerisation and phosphoacceptor domain	Domain
A, B	IPR036890	Histidine kinase/HSP90-like ATPase superfamily	Homologous Superfamily
A, B	IPR003594	Histidine kinase/HSP90-like ATPase domain	Domain
A, B	IPR005467	Histidine kinase domain	Domain
A, B	IPR050482	Sensor Histidine Kinase Two-Component System	Family
A, B	IPR003018	GAF domain	Domain
A, B	IPR029016	GAF-like domain superfamily	Homologous Superfamily

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.