S
IPR016131

Haemerythrin, iron-binding site

InterPro entry
Short nameHaemerythrin_Fe_BS

Description

The hemerythrin family is composed of hemerythrin proteins found in invertebrates, and a broader collection of bacterial and archaeal homologues. Hemerythrin is an oxygen-binding protein found in the vascular system and coelomic fluid, or in muscles (myohemerythrin) in invertebrates
[1]
. Many of the homologous proteins found in prokaryotes are multi-domain proteins with signal-transducing domains such as the GGDEF diguanylate cyclase domain (
IPR000160
) and methyl-accepting chemotaxis protein (MCP) signalling domain (
IPR004089
). Most hemerythrins 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.

Hemerythrins and myohemerythrins
[2, 3]
are small proteins of about 110 to 129 amino acid residues that bind two iron atoms. They are left-twisted 4-α-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
[4]
. In both hemerythrins and myohemerythrins, the active centre is a binuclear iron complex, bound directly to the protein via 7 amino acid side chains
[4]
, 5 His, 1 Glu and 1 Asp
[1]
. Ovohemerythrin
[5]
, a yolk protein from the leech Theromyzon tessulatum seems to belong to this family of proteins, it may play a role in the detoxification of free iron after a blood meal
[5]
.

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.

References

1.Primary structure of myohemerythrin from the annelid Nereis diversicolor. Takagi T, Cox JA. FEBS Lett. 285, 25-7, (1991). View articlePMID: 2065779

2.Structure of myohemerythrin in the azidomet state at 1.7/1.3 A resolution. Sheriff S, Hendrickson WA, Smith JL. J. Mol. Biol. 197, 273-96, (1987). View articlePMID: 3681996

3.The amino acid sequence of hemerythrin from Siphonosoma cumanense. Uchida T, Yano H, Satake K, Kubota I, Tsugita A. Protein Seq. Data Anal. 3, 141-7, (1990). PMID: 2362933

4.Active site structures of deoxyhemerythrin and oxyhemerythrin. Stenkamp RE, Sieker LC, Jensen LH, McCallum JD, Sanders-Loehr J. Proc. Natl. Acad. Sci. U.S.A. 82, 713-6, (1985). View articlePMID: 3856224

5.Ovohemerythrin, a major 14-kDa yolk protein distinct from vitellogenin in leech. Baert JL, Britel M, Sautiere P, Malecha J. Eur. J. Biochem. 209, 563-9, (1992). View articlePMID: 1425663

GO terms

biological process

  • None

cellular component

  • None

Cross References

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