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7  structures 2149  species 0  interactions 2649  sequences 3  architectures

Family: LolA (PF03548)

Summary: Outer membrane lipoprotein carrier protein LolA

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Outer membrane lipoprotein carrier protein LolA Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR004564

This protein, LolA, is known so far only in the gamma subdivision of the Proteobacteria. In Escherichia coli, lipoproteins are anchored to the periplasmic side of either the inner or outer membrane through N-terminal lipids, depending on the lipoprotein-sorting signal present at position 2 [PUBMED:12032293]. Five Lol proteins are involved in the sorting and outer membrane localization of lipoproteins. LolCDE, an ATP binding cassette (ABC) transporter, in the inner membrane releases outer membrane-directed lipoproteins from the inner membrane in an ATP-dependent manner, leading to the formation of a water-soluble complex between the lipoprotein and the molecular chaperone, LolA. The LolA-lipoprotein complex crosses the periplasm and then interacts with outer membrane receptor LolB, which is essential for the anchoring of lipoproteins to the outer membrane.

E. coli lipoproteins are anchored to the inner or outer membrane depending on the residue at position 2. Aspartate at this position makes lipoproteins specific to the inner membrane, whereas other residues cause the release of lipoproteins from the inner membrane.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

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 LolA_LolB (CL0048), which has the following description:

Gram-negative bacteria lipoproteins are anchored to the periplasmic surface of the inner or outer membrane depending on the sorting signal, which is the residue at position 2 of the polypeptide. Five Lol proteins are involved in the sorting and membrane localisation of lipoprotein. An ATP-binding cassette (ABC) transporter, LolCDE, releases outer membrane-specific lipoproteins from the inner membrane, causing the formation of a complex between the released lipoproteins and the periplasmic molecular chaperone LolA. When this complex interacts with outer membrane receptor LolB, the lipoproteins are transferred from LolA to LolB and then localised to the outer membrane. The structures of LolA and LolB are remarkably similar to each other. Both have a hydrophobic cavity consisting of an unclosed beta-barrel and an alpha-helical lid [1,2].

The clan contains the following 2 members:

LolA LolB

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
(39)
Full
(2649)
Representative proteomes NCBI
(1876)
Meta
(1519)
RP15
(183)
RP35
(390)
RP55
(523)
RP75
(649)
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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
(39)
Full
(2649)
Representative proteomes NCBI
(1876)
Meta
(1519)
RP15
(183)
RP35
(390)
RP55
(523)
RP75
(649)
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
(39)
Full
(2649)
Representative proteomes NCBI
(1876)
Meta
(1519)
RP15
(183)
RP35
(390)
RP55
(523)
RP75
(649)
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: TIGRFAMs
Previous IDs: none
Type: Family
Author: TIGRFAMs, Griffiths-Jones SR
Number in seed: 39
Number in full: 2649
Average length of the domain: 159.10 aa
Average identity of full alignment: 24 %
Average coverage of the sequence by the domain: 75.94 %

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 22.0 22.0
Trusted cut-off 22.0 22.0
Noise cut-off 21.8 21.9
Model length: 165
Family (HMM) version: 10
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 LolA domain has been found. There are 7 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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