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A novel ligand bound ABC transporter, LolCDE, provides insights into the molecular mechanisms underlying membrane detachment of bacterial lipoproteins
Author(s) -
Ito Yasuko,
Kanamaru Kyoko,
Taniguchi Naohiro,
Miyamoto Shigehiko,
Tokuda Hajime
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05378.x
Subject(s) - biology , atp binding cassette transporter , transporter , computational biology , ligand (biochemistry) , microbiology and biotechnology , genetics , gene , receptor
Summary The LolCDE complex of Escherichia coli belongs to the ABC transporter superfamily and initiates the lipoprotein sorting to the outer membrane by catalysing their release from the inner membrane. LolC and/or LolE, membrane subunits, recognize lipoproteins anchored to the outer surface of the inner membrane, while LolD hydrolyses ATP on its inner surface. We report here that ligand‐bound LolCDE can be purified from the inner membrane in the absence of ATP. Liganded LolCDE represents an intermediate of the release reaction and exhibits higher affinity for ATP than the unliganded form. ATP binding to LolD weakens the interaction between LolCDE and lipoproteins and causes their dissociation in a detergent solution, while lipoprotein release from membranes requires ATP hydrolysis. Liganded LolCDE thus reveals molecular events brought about through ATP binding and hydrolysis. LolCDE is the first example of an ABC transporter purified with tightly bound native substrates. A single molecule of lipoprotein is found to bind per molecule of the LolCDE complex.