Maltose transport in membrane vesicles of Escherichia coli is linked to ATP hydrolysis.

Dean, David A.; Davidson, Amy L.; Nikaido, Hiroshi

doi:10.1073/pnas.86.23.9134

Cited by 54 publications

(21 citation statements)

References 20 publications

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“…The experimental conditions had to be adapted to this very strong iron chelator (stability constant, 33 for EDDA compared with 17 for dipyridyl). In fact, we could not observe any improved growth of E. coli H1443 transformed with plasmid pAA100 compared with growth of the untransformed strain on NB agar containing 0.1 mM EDDA.…”

Section: Resultsmentioning

confidence: 99%

“…The SfuB protein, like the FecCD proteins, is very hydrophobic and is located in the cytoplasmic membrane. The SfuC protein and the FecE protein are hydrophilic but associated with the cytoplasmic membrane and contain nucleotide-binding domains, so that both could drive the Sfu-mediated iron transport through ATP hydrolysis, as has been shown for histidine (5) and maltose transport (17).…”

Section: Resultsmentioning

confidence: 99%

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Iron transport systems of Serratia marcescens

1992

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Serratia marcescens W225 expresses an unconventional iron(III) transport system. Uptake of Fe3+ occurs in the absence of an iron(III)-solubilizing siderophore, of an outer membrane receptor protein, and of the TonB and ExbBD proteins involved in outer membrane transport. The three SfuABC proteins found to catalyze iron(III) transport exhibit the typical features of periplasmic binding-protein-dependent systems for transport across the cytoplasmic membrane. In support of these conclusions, the periplasmic SfuA protein bound iron chloride and iron citrate but not ferrichrome, as shown by protection experiments against degradation by added V8 protease. The cloned sfuABC genes conferred upon an Escherichia coli aroB mutant unable to synthesize its own enterochelin siderophore the ability to grow under iron-limiting conditions (in the presence of 0.2 mM 2.2'-dipyridyl). Under extreme iron deficiency (0.4 mM 2.2'-dipyridyl), however, the entry rate of iron across the outer membrane was no longer sufficient for growth. Citrate had to be added in order for iron(III) to be translocated as an iron citrate complex in a FecA-and TonB-dependent manner through the outer membrane and via SfuABC across the cytoplasmic membrane. FecA-and TonB-dependent iron transport across the outer membrane could be clearly correlated with a very low concentration of iron in the medium. Expression of the sfuABC genes in E. coli was controlled by the Fur iron repressor gene. S. marcescens W225 was able to synthesize enterochelin and take up iron(III) enterochelin. It contained an iron(III) aerobactin transport system but lacked aerobactin synthesis. This strain was able to utilize the hydroxamate siderophores ferrichrome, coprogen, ferrioxamine B, rhodotorulic acid, and schizokinen as sole iron sources and grew on iron citrate as well. In contrast to E. coli K-12, S. marcescens could utilize heme. DNA fragments of the E. coli fhuA, iut, exbB, and fur genes hybridized with chromosomal S. marcescens DNA fragments, whereas no hybridization was obtained between S. marcescens chromosomal DNA and E. colifecA,JhuE, and tonB gene fragments. The presence of multiple iron transport systems was also indicated by the increased synthesis of at least five outer membrane proteins (in the molecular weight range of 72,000 to 87,000) after growth in low-iron media. Serratia liquefaciens and Serratia ficaria produced aerobactin, showing that this siderophore also occurs in the genus Serratia.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Iron transport systems of Serratia marcescens

1992

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“…MalK has been shown to have several distinct functions in the cell. First, MalK contains a well-defined nucleotide-binding fold (Walker boxes A and B) that has been shown to be essential for the hydrolysis of ATP that energizes maltose transport (4,6,9,23). Second, MalK contributes to the regulation of mal gene expression by an uncharacterized (and possibly indirect) interaction with the mal transcriptional activator, MalT (17).…”

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confidence: 99%

MalFGK complex assembly and transport and regulatory characteristics of MalK insertion mutants

Lippincott

Traxler

1997

J Bacteriol

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MalK is a peripheral cytoplasmic membrane protein that has multiple activities in Escherichia coli. It associates with integral cytoplasmic membrane proteins MalF and MalG to form the maltose transport complex (MalFGK), a member of the ATP-binding cassette (ABC) superfamily of proteins. In addition, MalK participates in two different regulatory pathways which modulate mal gene expression and MalFGK transport activity. We have created a set of malK mutations for analysis of the protein's structure and folding. These mutations, distributed throughout malK, are all similar insertions of 31 codons. The ability of each mutant to function in maltose transport and MalK-dependent regulation was characterized. Furthermore, we have exploited a sensitive biochemical assay to classify our MalK insertion mutants into two additional categories: MalFGK complex assembly proficient and complex assembly defective. The regions containing the insertions in the assembly-proficient class should correspond to areas within MalK that are surface exposed within the MalFGK complex. Affected regions in assembly-deficient mutants may be involved in critical structural contacts within the complex. One mutant apparently blocks assembly at an intermediate stage prior to oligomerization of the final MalFGK complex. This work contributes to the analysis of ABC transport proteins and to the study of the assembly process for hetero-oligomeric membrane proteins.Maltose transport across the cytoplasmic membrane of Escherichia coli utilizes a periplasmic binding protein-dependent transporter which is a member of the ATP-binding cassette (ABC or traffic ATPase) superfamily of proteins (reviewed in references 2, 8, and 14). In addition to the prokaryotic binding protein-dependent transporters, the ABC superfamily also includes several medically important eukaryotic proteins, including mammalian P-glycoprotein of multidrug-resistant tumor cells and the cystic fibrosis transmembrane conductance regulator. The maltose permease is a heterotetrameric complex comprised of integral membrane proteins MalF and MalG, which associate with peripheral membrane protein MalK in the stochiometry MalFGK 2 (4). Our goal is to characterize the assembly and folding of the MalFGK 2 complex to better understand the process of tertiary and quaternary folding of membrane proteins and the structural and functional interactions within the complex. Knowledge gained by the study of maltose permease also should contribute to the structure-function analysis of the other ABC superfamily proteins.Here, we describe the results of our mutagenesis of the gene coding for MalK, which is the domain of the maltose transporter with the most extensive homology to other ABC transporters. MalK has been shown to have several distinct functions in the cell. First, MalK contains a well-defined nucleotide-binding fold (Walker boxes A and B) that has been shown to be essential for the hydrolysis of ATP that energizes maltose transport (4,6,9,23). Second, MalK contributes to the regulation of mal gen...

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“…Substitution of the lysine residue in domain I with glutamine or glutamate and of the aspartate in domain TI with asparagine or glutamate resulted in a complete inactivation of FhuC (5). ATP energization of the transport of histidine and maltose, taken up via periplasmicbinding protein-dependent transport, has been demonstrated (7,13); hence it has been inferred that ATP serves as an energy source for periplasmic-binding protein-dependent transport systems in general (1,2,4,24,32), including the one for iron hydroxamates.…”

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confidence: 99%