Summary

Zinc finger, ZZ type

Zinc finger present in dystrophin, CBP/p300. ZZ in dystrophin binds calmodulin. Putative zinc finger; binding not yet shown. Four to six cysteine residues in its sequence are responsible for coordinating zinc ions, to reinforce the structure [2].

Literature references

Ponting CP, Blake DJ, Davies KE, Kendrick-Jones J, Winder SJ; , Trends Biochem Sci 1996;21:11-13.: ZZ and TAZ: new putative zinc fingers in dystrophin and other proteins. PUBMED:8848831
Roberts RG; , Genome Biol 2001;2:REVIEWS3006.: Dystrophins and dystrobrevins. PUBMED:11305946

InterPro entry IPR000433

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 PUBMED:10529348, PUBMED:15963892, PUBMED:15718139, PUBMED:17210253, PUBMED: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 PUBMED:11179890. Zinc-binding motifs are stable structures, and they rarely undergo conformational changes upon binding their target.

This entry represents ZZ-type zinc finger domains, named because of their ability to bind two zinc ions PUBMED:8848831. These domains contain 4-6 Cys residues that participate in zinc binding (plus additional Ser/His residues), including a Cys-X2-Cys motif found in other zinc finger domains. These zinc fingers are thought to be involved in protein-protein interactions. The structure of the ZZ domain shows that it belongs to the family of cross-brace zinc finger motifs that include the PHD, RING, and FYVE domains PUBMED:15476823. ZZ-type zinc finger domains are found in:

Transcription factors P300 and CBP.
Plant proteins involved in light responses, such as Hrb1.
E3 ubiquitin ligases MEX and MIB2 ().
Dystrophin and its homologues.

Single copies of the ZZ zinc finger occur in the transcriptional adaptor/coactivator proteins P300, in cAMP response element-binding protein (CREB)-binding protein (CBP) and ADA2. CBP provides several binding sites for transcriptional coactivators. The site of interaction with the tumour suppressor protein p53 and the oncoprotein E1A with CBP/P300 is a Cys-rich region that incorporates two zinc-binding motifs: ZZ-type and TAZ2-type. The ZZ-type zinc finger of CBP contains two twisted anti-parallel beta-sheets and a short alpha-helix, and binds two zinc ions PUBMED:15476823. One zinc ion is coordinated by four cysteine residues via 2 Cys-X2-Cys motifs, and the third zinc ion via a third Cys-X-Cys motif and a His-X-His motif. The first zinc cluster is strictly conserved, whereas the second zinc cluster displays variability in the position of the two His residues.

In Arabidopsis thaliana (Mouse-ear cress), the hypersensitive to red and blue 1 (Hrb1) protein, which regulating both red and blue light responses, contains a ZZ-type zinc finger domain PUBMED:15705950.

ZZ-type zinc finger domains have also been identified in the testis-specific E3 ubiquitin ligase MEX that promotes death receptor-induced apoptosis PUBMED:16522193. MEX has four putative zinc finger domains: one ZZ-type, one SWIM-type and two RING-type. The region containing the ZZ-type and RING-type zinc fingers is required for interaction with UbcH5a and MEX self-association, whereas the SWIM domain was critical for MEX ubiquitination.

In addition, the Cys-rich domains of dystrophin, utrophin and an 87kDa post-synaptic protein contain a ZZ-type zinc finger with high sequence identity to P300/CBP ZZ-type zinc fingers. In dystrophin and utrophin, the ZZ-type zinc finger lies between a WW domain (flanked by and EF hand) and the C-terminal coiled-coil domain. Dystrophin is thought to act as a link between the actin cytoskeleton and the extracellular matrix, and perturbations of the dystrophin-associated complex, for example, between dystrophin and the transmembrane glycoprotein beta-dystroglycan, may lead to muscular dystrophy. Dystrophin and its autosomal homologue utrophin interact with beta-dystroglycan via their C-terminal regions, which are comprised of a WW domain, an EF hand domain and a ZZ-type zinc finger domain PUBMED:17009962. The WW domain is the primary site of interaction between dystrophin or utrophin and dystroglycan, while the EF hand and ZZ-type zinc finger domains stabilise and strengthen this interaction.

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

Clan

This family is a member of clan C1 (CL0006), which contains the following 5 members:

C1_1 C1_2 C1_3 C1_4 ZZ

Gene Ontology

Molecular function

zinc ion binding (GO:0008270)

External database links

PANDIT:	PF00569
SYSTERS:	ZZ

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Alignment:	Seed (10) Full (1017) NCBI (1553) Metagenomics (25)
Viewer:

Formatting options

Alignment:	Seed (10) Full (1017)
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

Pfam alignments:	Seed (10) Full (1017) NCBI (1553) Metagenomics (25)
Full length sequences	Full-sequences (1017)

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER2.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Alignment kindly provided by SMART

Previous IDs:

none

Type:

Domain

Author:

SMART

Number in seed:

10

Number in full:

1017

Average length of the domain:

44.50 aa

Average identity of full alignment:

31 %

Average coverage of the sequence by the domain:

4.86 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 9421015 -E 1000 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	21.2	21.2
Trusted cut-off	21.2	21.2
Noise cut-off	21.1	21.1

Model length:

46

Family (HMM) version:

10

Download:

download the raw HMM for this family

Species distribution

Tree controls

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The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
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select a sub-tree or a set of species within the tree and view them graphically or as an alignment
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Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the ZZ domain has been found.

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Family: ZZ (PF00569)

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