K Homology domain (IPR004087)

Short name: KH_dom

Overlapping homologous superfamilies

Domain relationships


The K homology (KH) domain was first identified in the human heterogeneous nuclear ribonucleoprotein (hnRNP) K. An evolutionarily conserved sequence of around 70 amino acids, the KH domain is present in a wide variety of nucleic acid-binding proteins. The KH domain binds RNA, and can function in RNA recognition [PMID: 17437720]. It is found in multiple copies in several proteins, where they can function cooperatively or independently. For example, in the AU-rich element RNA-binding protein KSRP, which has 4 KH domains, KH domains 3 and 4 behave as independent binding modules to interact with different regions of the AU-rich RNA targets [PMID: 17437720]. The solution structure of the first KH domain of FMR1 [PMID: 9302998] and of the C-terminal KH domain of hnRNP K [PMID: 10369774] determined by nuclear magnetic resonance (NMR) revealed a beta-alpha-alpha-beta-beta-alpha structure. Proteins containing KH domains include:

  • Bacterial and organelle PNPases [PMID: 17337072].
  • Archaeal and eukaryotic exosome subunits [PMID: 17159918].
  • Eukaryotic and prokaryotic RS3 ribosomal proteins [PMID: 1160884].
  • Vertebrate fragile X mental retardation protein 1 (FMR1) [PMID: 15805463].
  • Vigilin, which has 14 KH domains [PMID: 14618268].
  • AU-rich element RNA-binding protein KSRP.
  • hnRNP K, which contains 3 KH domains.
  • Human onconeural ventral antigen-1 (NOVA-1) [PMID: 10368286].

According to structural analyses [PMID: 9302998, PMID: 10369774, PMID: 11160884], the KH domain can be separated in two groups - type 1 and type 2.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003676 nucleic acid binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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