Domain

K Homology domain, type 2 (IPR004044)

Short name: KH_dom_type_2

Domain relationships

Description

The K homology (KH) domain was first identified in the human heterogeneous nuclear ribonucleoprotein (hnRNP) K. It is a domain of around 70 amino acids that is present in a wide variety of quite diverse nucleic acid-binding proteins [PMID: 8036511]. It has been shown to bind RNA [PMID: 9302998, PMID: 10369774]. Like many other RNA-binding motifs, KH motifs are found in one or multiple copies (14 copies in chicken vigilin) and, at least for hnRNP K (three copies) and FMR-1 (two copies), each motif is necessary for in vitro RNA binding activity, suggesting that they may function cooperatively or, in the case of single KH motif proteins (for example, Mer1p), independently [PMID: 8036511].

According to structural analyses [PMID: 9302998, PMID: 10369774, PMID: 11160884], the KH domain can be separated in two groups. The first group or type-1 contain a beta-alpha-alpha-beta-beta-alpha structure, whereas in the type-2 the two last beta-sheets are located in the N-terminal part of the domain (alpha-beta-beta-alpha-alpha-beta). Sequence similarity between these two folds are limited to a short region (VIGXXGXXI) in the RNA binding motif. This motif is located between helice 1 and 2 in type-1 and between helice 2 and 3 in type-2. Proteins known to contain a type-2 KH domain include eukaryotic and prokaryotic S3 family of ribosomal proteins, and the prokaryotic GTP-binding protein era.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003723 RNA binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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