Uptake or extrusion: crystal structures of full ABC transporters suggest a common mechanism

Dawson, Roger; Hollenstein, Kaspar; Locher, Kaspar P.

doi:10.1111/j.1365-2958.2007.05792.x

Cited by 140 publications

(136 citation statements)

References 50 publications

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“…All together, the cytosolic protrusions of TMD helices generate four intracellular loops (IL1-IL4) that contain the so-called coupling helices. These run parallel to the plane of the membrane and interact with the NBDs [36,52,53]. Due to the twisted arrangement of the transmembrane spanning segments, IL2 and IL4, each located in a different half transporter or half monomer, interact exclusively with the trans-NBD (in the opposite half), while IL1 and IL3 only interact with the cis-NBD.…”

Section: General Structural Features Of Abc Transportersmentioning

confidence: 99%

“…Due to the twisted arrangement of the transmembrane spanning segments, IL2 and IL4, each located in a different half transporter or half monomer, interact exclusively with the trans-NBD (in the opposite half), while IL1 and IL3 only interact with the cis-NBD. Besides, TM6 finishes in a cytoplasmic α-helix extension located just upstream of the NBD domain of each half monomer [39,40,52]. These interactions may allow for intramolecular communication between the NBDs and the TMD within the ABC transporter.…”

Section: General Structural Features Of Abc Transportersmentioning

confidence: 99%

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Structure and mechanism of ATP-dependent phospholipid transporters

López‐Marqués

Poulsen

Bailly

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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Background: ATP-binding cassette (ABC) transporters and P4-ATPases are two large and seemingly unrelated families of primary active pumps involved in moving phospholipids from one leaflet of a biological membrane to the other. Scope of review: This review aims to identify common mechanistic features in the way phospholipid flipping is carried out by two evolutionarily unrelated families of transporters. Major conclusions: Both protein families hydrolyze ATP, although they employ different mechanisms to use it, and have a comparable size with twelve transmembrane segments in the functional unit. Further, despite differences in overall architecture, both appear to operate by an alternating access mechanism and during transport they might allow access of phospholipids to the internal part of the transmembrane domain. The latter feature is obvious for ABC transporters, but phospholipids and other hydrophobic molecules have also been found embedded in P-type ATPase crystal structures. Taken together, in two diverse groups of pumps, nature appears to have evolved quite similar ways of flipping phospholipids. General significance: Our understanding of the structural basis for phospholipid flipping is still limited but it seems plausible that a general mechanism for phospholipid flipping exists in nature. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.

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Section: General Structural Features Of Abc Transportersmentioning

confidence: 99%

Section: General Structural Features Of Abc Transportersmentioning

confidence: 99%

Structure and mechanism of ATP-dependent phospholipid transporters

López‐Marqués

Poulsen

Bailly

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…After ATP hydrolysis, the transporter returns its binding site to the cytoplasmic face to allow the substrate to enter the cytoplasm. This is known as the alternating access model of maltose transport (4) and may be a common mechanism among ABC transporters (2,9,10).…”

mentioning

confidence: 99%

Studies of the Maltose Transport System Reveal a Mechanism for Coupling ATP Hydrolysis to Substrate Translocation without Direct Recognition of Substrate

Gould

Shilton

2010

Journal of Biological Chemistry

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The ATPase activity of the maltose transporter (MalFGK 2 ) is dependent on interactions with the maltose-binding protein (MBP). To determine whether direct interactions between the translocated sugar and MalFGK 2 are important for the regulation of ATP hydrolysis, we used an MBP mutant (sMBP) that is able to bind either maltose or sucrose. We observed that maltose-and sucrose-bound sMBP stimulate equal levels of MalFGK 2 ATPase activity. Therefore, the ATPase activity of MalFGK 2 is coupled to translocation of maltose solely by interactions between MalFGK 2 and MBP. For both maltose and sucrose, the ability of sMBP to stimulate the ATP-binding cassette (ABC)2 transporters move various substrates across membranes, with substrate movement coupled to the hydrolysis of ATP. Although the ATPase activity of ABC exporters like P-glycoprotein is generally stimulated by substrate binding, the ATPase activity of ABC importers is activated by a peripheral substrate-binding protein and not the free substrate (for recent reviews see Refs.

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“…The functions of ABC transporters have been clarified by detailed studies of crystal structures [19,20]. It would be interesting and important to know how the accessory protein LptC affects the three-dimensional organization of LptBFG complex and thereby contributes to LPS transport.…”

Section: Lptc May Cause the Conformational Change Of Lptbfgmentioning

confidence: 99%

Characterization of lipopolysaccharide transport protein complex

Xiang

Wang

et al. 2013

Open Life Sciences

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Lipopolysaccharide (LPS) is an essential component of the outer membranes (OM) of most Gram-negative bacteria, which plays a crucial role in protection of the bacteria from toxic compounds and harsh conditions. The LPS is biosynthesized at the cytoplasmic side of inner membrane (IM), and then transported across the aqueous periplasmic compartment and assembled correctly at the outer membrane. This process is accomplished by seven LPS transport proteins (LptA-G), but the transport mechanism remains poorly understood. Here, we present findings by pull down assays in which the periplasmic component LptA interacts with both the IM complex LptBFGC and the OM complex LptDE in vitro, but not with complex LptBFG. Using purified Lpt proteins, we have successfully reconstituted the seven transport proteins as a complex in vitro. In addition, the LptC may play an essential role in regulating the conformation of LptBFG to secure the lipopolysaccharide from the inner membrane. Our results contribute to the understanding of lipopolysaccharide transport mechanism and will provide a platform to study the detailed mechanism of the LPS transport in vitro

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Uptake or extrusion: crystal structures of full ABC transporters suggest a common mechanism

Cited by 140 publications

References 50 publications

Structure and mechanism of ATP-dependent phospholipid transporters

Structure and mechanism of ATP-dependent phospholipid transporters

Studies of the Maltose Transport System Reveal a Mechanism for Coupling ATP Hydrolysis to Substrate Translocation without Direct Recognition of Substrate

Characterization of lipopolysaccharide transport protein complex

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