| Type: | Binding_site | Name: | Haemerythrin, iron-binding site |
| Description: | The haemerythrin family is composed of haemerythrin proteins found in invertebrates, and a broader collection of bacterial and archaeal homologues. Haemerythrin is an oxygen-binding protein found in the vascular system and coelemic fluid, or in muscles (myohaemerythrin) in invertebrates []. Many of the homologous proteins found in prokaryotes are multi-domain proteins with signal-transducing domains such as the GGDEF diguanylate cyclase domain () and methyl-accepting chemotaxis protein (MCP) signalling domain (). Most haemerythrins are oxygen-carriers with a bound non-haem iron, but at least one example is a cadmium-binding protein, apparently with a role in sequestering toxic metals rather than in binding oxygen. The prokaryote with the most instances of this domain is Magnetococcus sp. MC-1, a magnetotactic bacterium.Haemerythrins and myohaemerythrins [, ] are small proteins of about 110 to 129 amino acid residues that bind two iron atoms. They are left-twisted 4-alpha-helical bundles, which provide a hydrophobic pocket where dioxygen binds as a peroxo species, interacting with adjacent aliphatic side chains via van der Waals forces []. In both haemerythrins and myohaemerythrins, the active centre is a binuclear iron complex, bound directly to the protein via 7 amino acid side chains [], 5 His, 1 Glu and 1 Asp []. Ovohaemerythrin [], a yolk protein from the leech Theromyzon tessulatumseems to belong to this family of proteins, it may play a role in the detoxification of free iron after a blood meal [].This entry represents the iron-binding site found in haemerythrin and in related proteins. This site is located in the central region of these proteins and contains four of the iron-ligands: three histidines and a glutamate or glutamine. | Short Name: | Haemerythrin_Fe_BS |
