GAF domain
IPR003018
Definition
The GAF domain is named after some of the proteins it is found in, including cGMP-specific phosphodiesterases, adenylyl cyclases and FhlA. It is also found in guanylyl cyclases and phytochromes [[cite:PMID:9433123], [cite:PMID:20004158]]. The structure of a GAF domain shows that the domain shares a similar fold with the PAS domain PMID:11032796. 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 PMID:20298248. The GAF domain is also found in FhlA (formate hydrogen lyase transcriptional activator) and NifA, a transcriptional activator required for activation of most Nif operons, which are directly involved in nitrogen fixation. NifA interacts with sigma-54 PMID:1404379.
7 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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