2K2N

Solution structure of a cyanobacterial phytochrome GAF domain in the red light-absorbing ground state


Domain Annotation: SCOP Classification SCOP Database (version: 2.0) Homepage

ChainDomainClassArchitectureTopologyHomology
A3.30.450.40 Alpha Beta 2-Layer Sandwich Beta-Lactamase GAF domain

Protein Family Annotation Pfam Database Homepage

ChainsAccessionIdentifierDescriptionCommentsSource
APF00512His Kinase A (phospho-acceptor) domain (HisKA)His Kinase A (phospho-acceptor) domainDimerisation and phospho-acceptor domain of histidine kinases.Domain
APF01590GAF domain (GAF)GAF domainThis 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.
Domain
APF02518Histidine kinase-, DNA gyrase B-, and HSP90-like ATPase (HATPase_c)Histidine kinase-, DNA gyrase B-, and HSP90-like ATPaseThis family represents the structurally related ATPase domains of histidine kinase, DNA gyrase B and HSP90.Domain
APF00360Phytochrome region (PHY)Phytochrome region- Family