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117  structures 5529  species 0  interactions 10080  sequences 20  architectures

Family: ZnuA (PF01297)

Summary: Zinc-uptake complex component A periplasmic

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Zinc-uptake complex component A periplasmic Provide feedback

ZnuA includes periplasmic solute binding proteins such as TroA that interacts with an ATP-binding cassette transport system in Treponema pallidum [1]. ZnuA is part of the bacterial zinc-uptake complex ZnuABC, whose components are the following families, ZinT, PF09223 PF00950 PF00005 all of which are regulated by the transcription-regulator family FUR, PF01475. ZinT acts as a Zn2+-buffering protein that delivers Zn2+ to ZnuA (TroA), a high-affinity zinc-uptake protein. In Gram-negative bacteria the ZnuABC transporter system ensures an adequate import of zinc in Zn2+-poor environments, such as those encountered by pathogens within the infected host [2,3].

Literature references

  1. Lee YH, Deka RK, Norgard MV, Radolf JD, Hasemann CA; , Nat Struct Biol 1999;6:628-633.: Treponema pallidum TroA is a periplasmic zinc-binding protein with a helical backbone. PUBMED:10404217 EPMC:10404217

  2. Gabbianelli R, Scotti R, Ammendola S, Petrarca P, Nicolini L, Battistoni A;, BMC Microbiol. 2011;11:36.: Role of ZnuABC and ZinT in Escherichia coli O157:H7 zinc acquisition and interaction with epithelial cells. PUBMED:21338480 EPMC:21338480

  3. Ilari A, Alaleona F, Tria G, Petrarca P, Battistoni A, Zamparelli C, Verzili D, Falconi M, Chiancone E;, Biochim Biophys Acta. 2014;1840:535-544.: The Salmonella enterica ZinT structure, zinc affinity and interaction with the high-affinity uptake protein ZnuA provide insight into the management of periplasmic zinc. PUBMED:24128931 EPMC:24128931

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR006127

Members of this family constitute the solute-binding protein component of cluster-9 ABC transporters. This family includes periplasmic solute binding protein TroA from Treponema pallidum, which binds Zn2+ and Mn2+ [ PUBMED:17581125 ]. In Streptococcus suis, TroA is required for manganese acquisition [ PUBMED:21784944 ]. Related proteins are found in both Gram-positive and Gram-negative bacteria, including manganese-binding lipoprotein MntA [ PUBMED:16194238 ] and high-affinity zinc uptake system protein ZnuA [ PUBMED:24128931 ].

ZnuA is part of the bacterial zinc-uptake complex ZnuABC. ZinT acts as a Zn2+-buffering protein that delivers Zn2+ to ZnuA, a high-affinity zinc-uptake protein. In Gram-negative bacteria the ZnuABC transporter system ensures an adequate import of zinc in Zn2+-poor environments, such as those encountered by pathogens within the infected host [ PUBMED:21338480 , PUBMED:24128931 ].

Gene Ontology

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Domain organisation

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

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Pfam Clan

This family is a member of clan Chelatase (CL0043), which has the following description:

Metallated tetrapyrroles are used as prosthetic groups in proteins involved in biologically important processes such as photosynthesis, oxygen transport, drug metabolism and nitric oxide synthesis. In living organisms, metallation is catalysed by a group of enzymes called chelatases. This clan contains ferrochelatase (heme) and cobalt chelatase [1].

The clan contains the following 7 members:

CbiK CbiX DUF3364 Ferrochelatase Oxidored_nitro Peripla_BP_2 ZnuA


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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

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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...


This page displays the phylogenetic tree for this family's seed alignment. 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 alignment.

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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 View help on the curation process

Seed source: Pfam-B_1416 (release 3.0)
Previous IDs: Lipoprotein_4; SBP_bac_9; TroA;
Type: Family
Sequence Ontology: SO:0100021
Author: Finn RD , Bateman A
Number in seed: 945
Number in full: 10080
Average length of the domain: 277.60 aa
Average identity of full alignment: 23 %
Average coverage of the sequence by the domain: 86.12 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild --amino -o /dev/null --hand HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 29.0 29.0
Trusted cut-off 29.0 29.1
Noise cut-off 28.9 28.9
Model length: 247
Family (HMM) version: 19
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe 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 ZnuA domain has been found. There are 117 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
O07257 View 3D Structure Click here
P39172 View 3D Structure Click here
Q2G1U8 View 3D Structure Click here
Q2G2D8 View 3D Structure Click here