Gaf Domain
INTERPRO description (entry IPR003018 )
This domain is present in phytochromes and cGMP-specific phosphodiesterases. cGMP-dependent 3',5'-cyclic phosphodiesterase () catalyses the conversion of guanosine 3',5'-cyclic phosphate to guanosine 5'-phosphate. A phytochrome is a regulatory photoreceptor which exists in 2 forms that are reversibly interconvertible by light, the PR form that absorbs maximally in the red region of the spectrum, and the PFR form that absorbs maximally in the far-red region. This domain is also found in 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.
Pfam: GAF http://www.sanger.ac.uk//cgi-bin/Pfam/getacc?PF01590
Zoraghi et al. Properties and Functions of GAF Domains in Cyclic Nucleotide Phosphodiesterases and Other Proteins
Olfactory receptor
http://compbio.chemistry.uq.edu.au/mediawiki/upload/2/20/Olfactory_cGMP_PDE2.PDF
