Protein Domain : IPR011917

Type:  Family Name:  ABC transporter, lipid A export, MsbA
Description:  ABC transporters belong to the ATP-Binding Cassette (ABC) superfamily, which uses the hydrolysis of ATP to energise diverse biological systems. ABC transporters minimally consist of two conserved regions: a highly conserved ATP binding cassette (ABC) and a less conserved transmembrane domain (TMD). These can be found on the same protein or on two different ones. Most ABC transporters function as a dimer and therefore are constituted of four domains, two ABC modules and two TMDs.ABC transporters are involved in the export or import of a wide variety of substrates ranging from small ions to macromolecules. The major function of ABC import systems is to provide essential nutrients to bacteria. They are found only in prokaryotes and their four constitutive domains are usually encoded by independent polypeptides (two ABC proteins and two TMD proteins). Prokaryotic importers require additional extracytoplasmic binding proteins (one or more per systems) for function. In contrast, export systems are involved in the extrusion of noxious substances, the export of extracellular toxins and the targeting of membrane components. They are found in all living organisms and in general the TMD is fused to the ABC module in a variety of combinations. Some eukaryotic exporters encode the four domains on the same polypeptide chain [].The ABC module (approximately two hundred amino acid residues) is known to bind and hydrolyse ATP, thereby coupling transport to ATP hydrolysis in a large number of biological processes. The cassette is duplicated in several subfamilies. Its primary sequence is highly conserved, displaying a typical phosphate-binding loop: Walker A, and a magnesium binding site: Walker B. Besides these two regions, three other conserved motifs are present in the ABC cassette: the switch region which contains a histidine loop, postulated to polarise the attaching water molecule for hydrolysis, the signature conserved motif (LSGGQ) specific to the ABC transporter, and the Q-motif (between Walker A and the signature), which interacts with the gamma phosphate through a water bond. The Walker A, Walker B, Q-loop and switch region form the nucleotide binding site [, , ].The 3D structure of a monomeric ABC module adopts a stubby L-shape with two distinct arms. ArmI (mainly beta-strand) contains Walker A and Walker B. The important residues for ATP hydrolysis and/or binding are located in the P-loop. The ATP-binding pocket is located at the extremity of armI. The perpendicular armII contains mostly the alpha helical subdomain with the signature motif. It only seems to be required for structural integrity of the ABC module. ArmII is in direct contact with the TMD. The hinge between armI and armII contains both the histidine loop and the Q-loop, making contact with the gamma phosphate of the ATP molecule. ATP hydrolysis leads to a conformational change that could facilitate ADP release. In the dimer the two ABC cassettes contact each other through hydrophobic interactions at the antiparallel beta-sheet of armI by a two-fold axis [, , , , , ].The ATP-Binding Cassette (ABC) superfamily forms one of the largest of all protein families with a diversity of physiological functions []. Several studies have shown that there is a correlation between the functional characterisation and the phylogenetic classification of the ABC cassette [, ]. More than 50 subfamilies have been described based on a phylogenetic and functional classification [, , ]; (for further information see http://www.tcdb.org/tcdb/index.php?tc=3.A.1).This family consists of a single polypeptide chain transporter in the ATP-binding cassette (ABC) transporter family, MsbA, which exports lipid A [, ]. It may also act in multidrug resistance. Lipid A, a part of lipopolysaccharide, is found in the outer leaflet of the outer membrane of most Gram-negative bacteria. Members of this family are restricted to the Proteobacteria (although lipid A is more broadly distributed) and often are clustered with lipid A biosynthesis genes []. Short Name:  ABC_transpr_lipidA
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0 Child Features

2 Contains

DB identifier Type Name
IPR003439 Domain ABC transporter-like
IPR017871 Conserved_site ABC transporter, conserved site

2 Cross Referencess

Identifier
PS51239
TIGR02203

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005524 IPR011917
GO:0034040 IPR011917
GO:0016021 IPR011917

3 Ontology Annotations

GO Term Gene Name
GO:0005524 IPR011917
GO:0034040 IPR011917
GO:0016021 IPR011917

0 Parent Features

6 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
28531.m000016 B9TCJ5 PAC:16801048 Ricinus communis 584  
Brdisv1pangenome1006763m.p PAC:33658848 Brachypodium distachyon Pangenome 735  
Brdisv1pangenome1007762m.p PAC:33640504 Brachypodium distachyon Pangenome 602  
Brdisv1BdTR11A1042817m.p PAC:35688925 Brachypodium distachyon BdTR11a 602  
Brdisv1BdTR11A1041563m.p PAC:35694334 Brachypodium distachyon BdTR11a 910  
Brdisv1BdTR11A1041760m.p PAC:35693515 Brachypodium distachyon BdTR11a 1010  

14 Publications

First Author Title Year Journal Volume Pages PubMed ID
            9872322
            9873074
            11421269
            1282354
            9640644
            11402022
            11080142
            11532960
            11421270
            11470432
            11988180
            12119303
            18024585
            19053284