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3.A.1.125.1
Lipoprotein translocation system (translocates lipoproteins from the inner membrane to periplasmic chaperone, LolA, which transfers the lipoproteins to an outer membrane receptor, LolB, which anchors the lipoprotein to the outer membrane of the Gram-negative bacterial cell envelope) (see 1.B.46; Narita et al., 2003; Ito et al., 2006; Watanabe et al., 2007). The structure of ligand-bound LolCDE has been solved (Ito et al., 2006). LolC and LolE each have 4 TMSs (1+3). Unlike most ATP binding cassette transporters mediating the transmembrane flux of substrates, the LolCDE complex catalyzes the extrusion of lipoproteins anchored to the outer leaflet of the inner membrane. The LolCDE complex is unusual in that it can be purified as a liganded form, which is an intermediate of the lipoprotein release reaction (Taniguchi and Tokuda, 2008). LolCDE has been reconstituted from separated subunits (Kanamaru et al., 2007).  LolE binds the outer membrane lipoprotein, PAL (Mizutani et al. 2013). The mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins has been reported (Sharma et al. 2021) who determined the cryo-EM structures of nanodisc-embedded LolCDE in the nucleotide-free and nucleotide-bound states at 3.8-Å and 3.5-Å resolution, respectively. The structural analyses, together with biochemical and mutagenesis studies, uncovered how LolCDE recognizes its substrate by interacting with the lipid and N-terminal peptide moieties of the lipoprotein, and identify the amide-linked acyl chain as the key element for LolCDE interaction. Upon nucleotide binding, the transmembrane helices and the periplasmic domains of LolCDE undergo large-scale, asymmetric movements, resulting in extrusion of the captured lipoprotein. Comparison of LolCDE and MacB revealed the conserved mechanism of type VII ABC transporters and emphasized the unique properties of LolCDE as a molecule extruder of triacylated lipoproteins (Sharma et al. 2021).

Accession Number:P0ADC3
Protein Name:LolC aka B1116
Length:399
Molecular Weight:43264.00
Species:Escherichia coli [83333]
Number of TMSs:4
Location1 / Topology2 / Orientation3: Cell inner membrane1 / Multi-pass membrane protein2
Substrate Lipoproteins

Cross database links:

RefSeq: AP_001742.1    NP_415634.1   
Entrez Gene ID: 945673   
Pfam: PF02687   
BioCyc: EcoCyc:YCFU-MONOMER    ECOL168927:B1116-MONOMER   
KEGG: ecj:JW5161    eco:b1116   

Gene Ontology

GO:0009276 C:Gram-negative-bacterium-type cell wall
GO:0016021 C:integral to membrane
GO:0005886 C:plasma membrane
GO:0006810 P:transport

References (4)

[1] “A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map.”  Oshima T.et.al.   8905232
[2] “The complete genome sequence of Escherichia coli K-12.”  Blattner F.R.et.al.   9278503
[3] “Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110.”  Hayashi K.et.al.   16738553
[4] “A new ABC transporter mediating the detachment of lipid-modified proteins from membranes.”  Yakushi T.et.al.   10783239
Structure:
5NAA   6F3Z   6F49     

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FASTA formatted sequence
1:	MYQPVALFIG LRYMRGRAAD RFGRFVSWLS TIGITLGVMA LVTVLSVMNG FERELQNNIL 
61:	GLMPQAILSS EHGSLNPQQL PETAVKLDGV NRVAPITTGD VVLQSARSVA VGVMLGIDPA 
121:	QKDPLTPYLV NVKQTDLEPG KYNVILGEQL ASQLGVNRGD QIRVMVPSAS QFTPMGRIPS 
181:	QRLFNVIGTF AANSEVDGYE MLVNIEDASR LMRYPAGNIT GWRLWLDEPL KVDSLSQQKL 
241:	PEGSKWQDWR DRKGELFQAV RMEKNMMGLL LSLIVAVAAF NIITSLGLMV MEKQGEVAIL 
301:	QTQGLTPRQI MMVFMVQGAS AGIIGAILGA ALGALLASQL NNLMPIIGVL LDGAALPVAI 
361:	EPLQVIVIAL VAMAIALLST LYPSWRAAAT QPAEALRYE