Summary: Outer membrane lipoprotein carrier protein LolA
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Outer membrane lipoprotein carrier protein LolA Provide feedback
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Internal database links
|Similarity to PfamA using HHSearch:||DUF2092|
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.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||outer membrane-bounded periplasmic space (GO:0030288)|
|Biological process||protein transport (GO:0015031)|
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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
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Curation and family details
|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 build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||10|
|Download:||download the raw HMM for this family|
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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 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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