Truncated hemoglobin, group 1 (IPR016339)

Short name: Hemoglobin_trunc_I

Overlapping homologous superfamilies

Family relationships


This entry represents a group of haemoglobin-like proteins found in eubacteria, cyanobacteria, protozoa, and plants, but not in animals or yeast [PMID: 11696555]. Truncated hemoglobins (TrHbs) have a truncated 2-over-2 rather than the canonical 3-over-3 alpha-helical sandwich fold [PMID: 15598493]. The variability of the amino acid residues of the heme pocket suggested their partition into three groups that share less than 30% sequence similarity with each other [PMID: 11696555]. This entry includes:

  • HbN (or GlbN): a truncated haemoglobin-like protein that binds oxygen cooperatively with a very high affinity and a slow dissociation rate, which may exclude it from oxygen transport. It appears to be involved in bacterial nitric oxide detoxification and in nitrosative stress [PMID: 16814781, PMID: 15783226].
  • Cyanoglobin (or GlbN): a truncated haemoprotein found in cyanobacteria that has high oxygen affinity, and which appears to serve as part of a terminal oxidase, rather than as a respiratory pigment [PMID: 10684619].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.