ABC transporters catalyzing carbohydrate uptake

Schneider, Erwin

doi:10.1016/s0923-2508(01)01201-3

Cited by 135 publications

(121 citation statements)

References 31 publications

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“…In contrast to all previous work reporting fitness effects of synonymous mutations, the two we The schematic depicts the probable subunit organization of the gene products during glucose uptake 40 . Glucose crosses the outer membrane by facilitated diffusion through the OprB porin, interacts with the periplasmic glucose-binding protein (GtsA) and is transported across the inner membrane channel (GtsBCD 2 ) in a process energized by ATP hydrolysis.…”

Section: Resultsmentioning

confidence: 97%

Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

2014

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Conventional wisdom holds that synonymous mutations, nucleotide changes that do not alter the encoded amino acid, have no detectable effect on phenotype or fitness. However, a growing body of evidence from both comparative and experimental studies suggests otherwise. Synonymous mutations have been shown to impact gene expression, protein folding and fitness, however, direct evidence that they can be positively selected, and so contribute to adaptation, is lacking. Here we report the recovery of two beneficial synonymous single base pair changes that arose spontaneously and independently in an experimentally evolved population of Pseudomonas fluorescens. We show experimentally that these mutations increase fitness by an amount comparable to non-synonymous mutations and that the fitness increases stem from increased gene expression. These results provide unequivocal evidence that synonymous mutations can drive adaptive evolution and suggest that this class of mutation may be underappreciated as a cause of adaptation and evolutionary dynamics.

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Section: Resultsmentioning

confidence: 97%

Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

2014

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“…Association of the MalK subunits with MalF and MalG requires the so-called "EAA" sequence motifs (consensus EAAX 3 GX 9 IXLP) that are conserved in the last cytoplasmic loop of TMDs of ABC import systems (18,19). MalK and closely related ABC subunits belonging to the CUT1 and MOI subfamilies of ABC importers (2,20) contain a unique C-terminal extension, which in the crystal structures of MalK (9) and CysA (21) contribute substantially to monomer-monomer contacts. The MalK structures further revealed that binding of ATP causes the nucleotide binding domains to close (9) and that ATP hydrolysis is required for resetting the system to the resting state (22).…”

Section: Atp-binding Cassette (Abc)mentioning

confidence: 99%

ATP-driven MalK Dimer Closure and Reopening and Conformational Changes of the “EAA” Motifs Are Crucial for Function of the Maltose ATP-binding Cassette Transporter (MalFGK2)

Daus

Grote

Müller

et al. 2007

Journal of Biological Chemistry

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We have investigated conformational changes of the purified maltose ATP-binding cassette transporter (MalFGK 2 ) upon binding of ATP. The transport complex is composed of a heterodimer of the hydrophobic subunits MalF and MalG constituting the translocation pore and of a homodimer of MalK, representing the ATP-hydrolyzing subunit. Substrate is delivered to the transporter in complex with periplasmic maltose-binding protein (MalE). Cross-linking experiments with a variant containing an A85C mutation within the Q-loop of each MalK monomer indicated an ATP-induced shortening of the distance between both monomers. Cross-linking caused a substantial inhibition of MalE-maltose-stimulated ATPase activity. We further demonstrated that a mutation affecting the "catalytic carboxylate" (E159Q) locks the MalK dimer in the closed state, whereas a transporter containing the "ABC signature" mutation Q140K permanently resides in the resting state. Cross-linking experiments with variants containing the A85C mutation combined with cysteine substitutions in the conserved EAA motifs of MalF and MalG, respectively, revealed close proximity of these residues in the resting state. The formation of a MalK-MalG heterodimer remained unchanged upon the addition of ATP, indicating that MalG-EAA moves along with MalK during dimer closure. In contrast, the yield of MalK-MalF dimers was substantially reduced. This might be taken as further evidence for asymmetric functions of both EAA motifs. Cross-linking also caused inhibition of ATPase activity, suggesting that transporter function requires conformational changes of both EAA motifs. Together, our data support ATP-driven MalK dimer closure and reopening as crucial steps in the translocation cycle of the intact maltose transporter and are discussed with respect to a current model. ATP-binding cassette (ABC)3 transporters are involved in the uptake or export of an enormous variety of substances ranging from small ions to large polypeptides at the expense of ATP. They are found in all organisms from bacteria to humans, and dysfunction is often associated with disease in humans, such as cystic fibrosis, adrenoleukodystrophy, or Stargardt's macular dystrophy (1). ABC transporters share a common architectural organization comprising two hydrophobic transmembrane domains (TMDs) that form the translocation pathway and two hydrophilic nucleotide binding (ABC) domains (NBDs) that hydrolyze ATP. In fact, in most prokaryote importers, TMDs and NBDs are expressed as separate protein subunits, whereas in most export systems of both prokaryotes and eukaryotes, they are usually fused into a single polypeptide chain (2).The ABC domains are characterized by a set of Walker A and B motifs that are involved in nucleotide binding and by the unique "LSGGQ" signature sequence (3). The crystal structures of several mostly prokaryotic NBDs have been reported that largely agree on the overall fold (reviewed in Refs. 4 -6). Accordingly, the cassette can be divided into a RecA-like subdomain encompassing both Walker m...

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“…ABC importers belong to two main families: the sugar ABC transport-, or carbohydrate uptake transporter (CUT)-family, and the di/oligopeptide transport-, or Opp-family [22]. These two families differ not only in substrate specificity but also in the architecture of the transport complex.…”

Section: Binding-protein-dependent Abc-type Transportersmentioning

confidence: 99%

Sugar transport in (hyper)thermophilic archaea

Koning

Albers

Konings

et al. 2002

Research in Microbiology

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Hyperthermophilic archaea show important metabolic adaptations for growth on carbohydrates under hostile conditions. For carbohydrate uptake so far only ABC-type transporters have been described that are equipped with a uniquely high affinity as compared to mesophilic bacterial systems. This allows these organisms to efficiently scavenge all available carbohydrates from the extreme environment.  2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.

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ABC transporters catalyzing carbohydrate uptake

Cited by 135 publications

References 31 publications

Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

ATP-driven MalK Dimer Closure and Reopening and Conformational Changes of the “EAA” Motifs Are Crucial for Function of the Maltose ATP-binding Cassette Transporter (MalFGK2)

Sugar transport in (hyper)thermophilic archaea

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