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9  structures 3512  species 0  interactions 7147  sequences 16  architectures

Family: Sec_GG (PF07549)

Summary: SecD/SecF GG Motif

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SecD/SecF GG Motif Provide feedback

This family consists of various prokaryotic SecD and SecF protein export membrane proteins. This SecD and SecF proteins are part of the multimeric protein export complex comprising SecA, D, E, F, G, Y, and YajC [1]. SecD and SecF are required to maintain a proton motive force [2]. This alignment encompasses a -GG- motif typically found in N-terminal half of the SecD/SecF proteins .

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR022646

Secretion across the inner membrane in some Gram-negative bacteria occurs via the preprotein translocase pathway. Proteins are produced in the cytoplasm as precursors, and require a chaperone subunit to direct them to the translocase component [PUBMED:2202721]. From there, the mature proteins are either targeted to the outer membrane, or remain as periplasmic proteins. The translocase protein subunits are encoded on the bacterial chromosome.

The translocase itself comprises 7 proteins, including a chaperone protein (SecB), an ATPase (SecA), an integral membrane complex (SecCY, SecE and SecG), and two additional membrane proteins that promote the release of the mature peptide into the periplasm (SecD and SecF) [PUBMED:2202721]. The chaperone protein SecB [PUBMED:11336818] is a highly acidic homotetrameric protein that exists as a "dimer of dimers" in the bacterial cytoplasm. SecB maintains preproteins in an unfolded state after translation, and targets these to the peripheral membrane protein ATPase SecA for secretion [PUBMED:10418149]. Together with SecY and SecG, SecE forms a multimeric channel through which preproteins are translocated, using both proton motive forces and ATP-driven secretion. The latter is mediated by SecA. The structure of the Escherichia coli SecYEG assembly revealed a sandwich of two membranes interacting through the extensive cytoplasmic domains [PUBMED:12167867]. Each membrane is composed of dimers of SecYEG. The monomeric complex contains 15 transmembrane helices.

The SecD and SecF equivalents of the Gram-positive bacterium Bacillus subtilis are jointly present in one polypeptide, denoted SecDF, that is required to maintain a high capacity for protein secretion. Unlike the SecD subunit of the pre-protein translocase of E. coli, SecDF of B. subtilis was not required for the release of a mature secretory protein from the membrane, indicating that SecDF is involved in earlier translocation steps [PUBMED:9694879]. Comparison with SecD and SecF proteins from other organisms revealed the presence of 10 conserved regions in SecDF, some of which appear to be important for SecDF function. Interestingly, the SecDF protein of B. subtilis has 12 putative transmembrane domains. Thus, SecDF does not only show sequence similarity but also structural similarity to secondary solute transporters [PUBMED:9694879].

This entry represents a GG-containing domain found in the N-terminal region of prokaryotic SecD and SecF protein export membrane proteins. It is found in association with . SecD and SecF proteins are part of the multimeric protein export complex comprising SecA, D, E, F, G, Y, and YajC [PUBMED:9694879]. SecD and SecF are required to maintain a proton motive force [PUBMED:8112309].

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
(145)
Full
(7147)
Representative proteomes NCBI
(5001)
Meta
(3208)
RP15
(506)
RP35
(1052)
RP55
(1384)
RP75
(1648)
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Format an alignment

  Seed
(145)
Full
(7147)
Representative proteomes NCBI
(5001)
Meta
(3208)
RP15
(506)
RP35
(1052)
RP55
(1384)
RP75
(1648)
Alignment:
Format:
Order:
Sequence:
Gaps:
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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
(145)
Full
(7147)
Representative proteomes NCBI
(5001)
Meta
(3208)
RP15
(506)
RP35
(1052)
RP55
(1384)
RP75
(1648)
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: Yeats C
Previous IDs: none
Type: Motif
Author: Yeats C
Number in seed: 145
Number in full: 7147
Average length of the domain: 30.00 aa
Average identity of full alignment: 30 %
Average coverage of the sequence by the domain: 6.74 %

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 20.3 12.0
Trusted cut-off 20.3 12.1
Noise cut-off 20.2 11.9
Model length: 31
Family (HMM) version: 9
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 Sec_GG domain has been found. There are 9 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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