KH

K homology RNA-binding domain
KH
SMART accession number:SM00322
Description: -
Interpro abstract (IPR004087):

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 [ (PUBMED: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 [ (PUBMED:17437720) ]. The solution structure of the first KH domain of FMR1 [ (PUBMED:9302998) ] and of the C-terminal KH domain of hnRNP K [ (PUBMED: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 [ (PUBMED:17337072) ].
  • Archaeal and eukaryotic exosome subunits [ (PUBMED:17159918) ].
  • Eukaryotic and prokaryotic RS3 ribosomal proteins [ (PUBMED:1160884) ].
  • Vertebrate fragile X mental retardation protein 1 (FMR1) [ (PUBMED:15805463) ].
  • Vigilin, which has 14 KH domains [ (PUBMED:14618268) ].
  • AU-rich element RNA-binding protein KSRP.
  • hnRNP K, which contains 3 KH domains.
  • Human onconeural ventral antigen-1 (NOVA-1) [ (PUBMED:10368286) ].

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

GO function:nucleic acid binding (GO:0003676)
Family alignment:
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There are 181505 KH domains in 115166 proteins in SMART's nrdb database.

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