Cyanobacteriochrome

Cyanobacteriochromes are phytochrome-related photoreceptor proteins found only in the cyanobacteria. Cyanobacteriochromes are phytochrome-related photoreceptor proteins found only in the cyanobacteria. Cyanobacteriochrome covalently binds a linear tetrapyrrole molecule in the GAF domain. The A-ring of linear tetrapyrrole molecule is anchored at cysteine residue in the GAF domain via thioether bond. The GAF domain of cyanobacteriochrome is related to phytochrome GAF, however, These GAF domains are distinct. A second cysteine linkage to the tetrapyrrole is found in some cyanobacteriochrome GAF domains resulting in blue-green photo reversible light sensitivity