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14  structures 840  species 0  interactions 4742  sequences 10  architectures

Family: Porin_4 (PF13609)

Summary: Gram-negative porin

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "General bacterial porin family". More...

General bacterial porin family Edit Wikipedia article

Gram-negative porin
1pho opm.png
Identifiers
Symbol Porin_1
Pfam PF00267
Pfam clan CL0193
InterPro IPR001702
PROSITE PDOC00498
SCOP 1mpf
SUPERFAMILY 1mpf
TCDB 1.B.1
OPM superfamily 31
OPM protein 1pho
CDD cd01345

General bacterial porins are a family of proteins from the outer membrane of Gram-negative bacteria. The porins act as molecular filters for hydrophilic compounds.[1] They are responsible for the 'molecular sieve' properties of the outer membrane. Porins form large water-filled channels which allow the diffusion of hydrophilic molecules into the periplasmic space. Some porins form general diffusion channels that allow any solutes up to a certain size (that size is known as the exclusion limit) to cross the membrane, while other porins are specific for one particular solute and contain a binding site for that solute inside the pores (these are known as selective porins). As porins are the major outer membrane proteins, they also serve as receptor sites for the binding of phages and bacteriocins.

General diffusion porins usually assemble as a trimer in the membrane and the transmembrane core of these proteins is composed exclusively of beta strands.[2] It has been shown[3] that a number of general porins are evolutionarily related, and these porins are:

Subfamilies

References

  1. ^ Benz R, Bauer K (1988). "Permeation of hydrophilic molecules through the outer membrane of gram-negative bacteria. Review on bacterial porins". Eur. J. Biochem. 176 (1): 1–19. doi:10.1111/j.1432-1033.1988.tb14245.x. PMID 2901351. 
  2. ^ Jap BK, Walian PJ (1990). "Biophysics of the structure and function of porins". Q. Rev. Biophys. 23 (4): 367–403. doi:10.1017/S003358350000559X. PMID 2178269. 
  3. ^ Pattus F, Jeanteur D, Lakey JH (1991). "The bacterial porin superfamily: sequence alignment and structure prediction". Mol. Microbiol. 5 (9): 2153–2164. doi:10.1111/j.1365-2958.1991.tb02145.x. PMID 1662760. 


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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.

Gram-negative porin Provide feedback

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Internal database links

External database links

This tab holds annotation information from the InterPro database.

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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 MBB (CL0193), which has the following description:

This clan gathers together a large set of beta barrel membrane proteins.Although these proteins have different numbers of beta strands in the barrel they have significant sequence similarity between families.

The clan contains the following 54 members:

Ail_Lom Autotransporter Bac_surface_Ag Campylo_MOMP Channel_Tsx CopB DUF1302 DUF1597 DUF2320 DUF2490 DUF2860 DUF3078 DUF3138 DUF3187 DUF3308 DUF3374 DUF3575 DUF4289 DUF481 DUF560 Gcw_chp HP_OMP HP_OMP_2 KdgM LamB Legionella_OMP MipA OMP_b-brl OMP_b-brl_2 OMP_b-brl_3 OmpA_membrane Omptin OmpW Opacity OpcA OprB OprD OprF OstA_C PagL Phenol_MetA_deg Porin_1 Porin_2 Porin_4 Porin_O_P Porin_OmpG ShlB Surface_Ag_2 Toluene_X TonB_dep_Rec TraF_2 TSA Usher YfaZ

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...

View options

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
(115)
Full
(4742)
Representative proteomes NCBI
(6841)
Meta
(1393)
RP15
(153)
RP35
(515)
RP55
(976)
RP75
(1423)
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(115)
Full
(4742)
Representative proteomes NCBI
(6841)
Meta
(1393)
RP15
(153)
RP35
(515)
RP55
(976)
RP75
(1423)
Alignment:
Format:
Order:
Sequence:
Gaps:
Download/view:

Download options

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
(115)
Full
(4742)
Representative proteomes NCBI
(6841)
Meta
(1393)
RP15
(153)
RP35
(515)
RP55
(976)
RP75
(1423)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

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: Jackhmmer:A3K5H9
Previous IDs: none
Type: Domain
Author: Bateman A
Number in seed: 115
Number in full: 4742
Average length of the domain: 323.20 aa
Average identity of full alignment: 20 %
Average coverage of the sequence by the domain: 89.64 %

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 27.0 27.0
Trusted cut-off 27.0 27.0
Noise cut-off 26.9 26.9
Model length: 311
Family (HMM) version: 1
Download: download the raw HMM for this family

Species distribution

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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 Porin_4 domain has been found. There are 14 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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