Domain

Zinc finger, DksA/TraR C4-type (IPR000962)

Short name: Znf_DskA_TraR

Domain relationships

Description

Zinc finger (Znf) domains are relatively small protein motifs which contain multiple finger-like protrusions that make tandem contacts with their target molecule. Some of these domains bind zinc, but many do not; instead binding other metals such as iron, or no metal at all. For example, some family members form salt bridges to stabilise the finger-like folds. They were first identified as a DNA-binding motif in transcription factor TFIIIA from Xenopus laevis (African clawed frog), however they are now recognised to bind DNA, RNA, protein and/or lipid substrates [PMID: 10529348, PMID: 15963892, PMID: 15718139, PMID: 17210253, PMID: 12665246]. Their binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. Znf domains are often found in clusters, where fingers can have different binding specificities. There are many superfamilies of Znf motifs, varying in both sequence and structure. They display considerable versatility in binding modes, even between members of the same class (e.g. some bind DNA, others protein), suggesting that Znf motifs are stable scaffolds that have evolved specialised functions. For example, Znf-containing proteins function in gene transcription, translation, mRNA trafficking, cytoskeleton organisation, epithelial development, cell adhesion, protein folding, chromatin remodelling and zinc sensing, to name but a few [PMID: 11179890]. Zinc-binding motifs are stable structures, and they rarely undergo conformational changes upon binding their target.

This entry represents domains identified in zinc finger-containing members of the DksA/TraR family. DksA is a critical component of the rRNA transcription initiation machinery that potentiates the regulation of rRNA promoters by ppGpp and the initiating NTP. In delta-dksA mutants, rRNA promoters are unresponsive to changes in amino acid availability, growth rate, or growth phase. In vitro, DksA binds to RNAP, reduces open complex lifetime, inhibits rRNA promoter activity, and amplifies effects of ppGpp and the initiating NTP on rRNA transcription [PMID: 15294156, PMID: 15294157]. The dksA gene product suppresses the temperature-sensitive growth and filamentation of a dnaK deletion mutant of Escherichia coli. Gene knockout [PMID: 2180916] and deletion [PMID: 8063112] experiments have shown the gene to be non-essential, mutations causing a mild sensitivity to UV light, but not affecting DNA recombination [PMID: 8063112]. In Pseudomonas aeruginosa, dksA is a novel regulator involved in the post-transcriptional control of extracellular virulence factor production [PMID: 12775693].

The proteins contain a C-terminal region thought to fold into a 4-cysteine zinc finger. Other proteins found to contain a similar zinc finger domain include:

  • the traR gene products encoded on the E. coli F and R100 plasmids [PMID: 8021201, PMID: 12932736]
  • the traR gene products encoded on Salmonella spp. plasmids pED208 and pSLT
  • the dnaK suppressor
  • hypothetical proteins from bacteria and bacteriophage
  • FHL4, LIM proteins from Homo sapiens (Human) and Mus musculus (Mouse) [PMID: 10049694]

More information about these proteins can be found at Protein of the Month: Zinc Fingers [].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008270 zinc ion 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