Segregation and condensation protein A (IPR003768)

Short name: ScpA

Overlapping homologous superfamilies


Family relationships



This family represents ScpA, which along with ScpB (IPR005234) interacts with SMC in vivo forming a complex that is required for chromosome condensation and segregation [PMID: 12065423, PMID: 12897137]. The SMC-Scp complex appears to be similar to the MukB-MukE-Muk-F complex in Escherichia coli [PMID: 10545099], where MukB (IPR007406) is the homologue of SMC. ScpA and ScpB have little sequence similarity to MukE (IPR007385) or MukF (IPR005582), they are predicted to be structurally similar, being predominantly alpha-helical with coiled coil regions.

In general scpA and scpB form an operon in most bacterial genomes. Flanking genes are highly variable suggesting that the operon has moved throughout evolution. Bacteria containing an smc gene also contain scpA or scpB but not necessarily both. An exception is found in Deinococcus radiodurans, which contains scpB but neither smc nor scpA. In the archaea the gene order SMC-ScpA is conserved in nearly all species, as is the very short distance between the two genes, indicating co-transcription of the both in different archaeal genera and arguing that interaction of the gene products is not confined to the homologues in Bacillus subtilis. It would seem probable that, in light of all the studies, SMC, ScpA and ScpB proteins or homologues act together in chromosome condensation and segregation in all prokaryotes [PMID: 12100548].

Contributing signatures

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