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6  structures 194  species 0  interactions 195  sequences 1  architecture

Family: HobA (PF12163)

Summary: DNA replication regulator

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The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

DNA replication regulator Provide feedback

This family of proteins is found exclusively in epsilon-proteobacteria. Proteins in this family are approximately 180 amino acids in length. The structure of HobA is a modified Rossmann fold consisting of a five-stranded parallel beta-sheet (beta1-5) flanked on one side by alpha-2, alpha-3 and alpha-6 helices and alpha-4 and alpha-5 on the other. The alpha-1 helix is extended away from and has minimal interaction with the globular part of the protein. Four monomers interact to form a tetrameric molecule. Four calcium atoms bind to the tetramer and these binding sites may have functional relevance. The function of HobA is to regulate DNA replication and its does this by binding to DNA-A, but the exact mechanism of how this regulation occurs is purely speculative

Literature references

  1. Natrajan G, Hall DR, Thompson AC, Gutsche I, Terradot L;, Mol Microbiol. 2007;65:995-1005.: Structural similarity between the DnaA-binding proteins HobA (HP1230) from Helicobacter pylori and DiaA from Escherichia coli. PUBMED:17683397 EPMC:17683397


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR021011

This family of proteins is found exclusively in epsilon-proteobacteria. Proteins in this family are approximately 180 amino acids in length. The crystal structure of HobA from Helicobacter pylori has been reported at 1.7A resolution; HobA represents a modified Rossmann fold consisting of a five-stranded parallel beta-sheet (beta1-5) flanked on one side by alpha-2, alpha-3 and alpha-6 helices and alpha-4 and alpha-5 on the other. The alpha-1 helix is extended away from and has minimal interaction with the globular part of the protein. Four monomers interact to form a tetrameric molecule. Four calcium atoms bind to the tetramer and these binding sites may have functional relevance. The closest structural homologue of HobA is a sugar isomerase (SIS) domain containing protein, the phosphoheptose isomerase from Pseudomonas aeruginosa. The SIS proteins share strong sequence homology with DiaA from Escherichia coli; yet, HobA and DiaA share no sequence homology [PUBMED:17683397].

HobA is a novel protein essential for initiation of H. pylori chromosome replication. It interacts specifically via DnaA with the oriC-DnaA complex. It is possible that HobA is essential for the correct formation and stabilisation of the orisome by facilitating the spatial positioning of DnaA at oriC [PUBMED:17645450].

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

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

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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.

  Seed
(15)
Full
(195)
Representative proteomes NCBI
(95)
Meta
(3)
RP15
(5)
RP35
(18)
RP55
(22)
RP75
(22)
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Format an alignment

  Seed
(15)
Full
(195)
Representative proteomes NCBI
(95)
Meta
(3)
RP15
(5)
RP35
(18)
RP55
(22)
RP75
(22)
Alignment:
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Sequence:
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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(15)
Full
(195)
Representative proteomes NCBI
(95)
Meta
(3)
RP15
(5)
RP35
(18)
RP55
(22)
RP75
(22)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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 HMMER3.

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'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.

Note: You can also download the data file for the tree.

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: pdb_2uvp
Previous IDs: none
Type: Domain
Author: Mistry J, Gavin OL
Number in seed: 15
Number in full: 195
Average length of the domain: 176.60 aa
Average identity of full alignment: 56 %
Average coverage of the sequence by the domain: 99.59 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.2 20.2
Trusted cut-off 20.8 79.2
Noise cut-off 19.8 19.6
Model length: 180
Family (HMM) version: 3
Download: download the raw HMM for this family

Species distribution

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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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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 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 HobA domain has been found. There are 6 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 seqence.

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