Novel Missense Mutations That Affect the Transport Function of MalK, the ATP-Binding-Cassette Subunit of the
            <i>Salmonella enterica</i>
            Serovar Typhimurium Maltose Transport System

Hunke, Sabine; Landmesser, Heidi; Schneider, Erwin

doi:10.1128/jb.182.5.1432-1436.2000

Cited by 24 publications

(19 citation statements)

References 21 publications

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“…Suppressor mutations in malK that restore transport were selected from these maltose-negative mutants, and they mapped mainly in the helical domain of MalK, consistent with the idea that the EAA regions constitute a recognition site for the helical domains of ABC ATPases. The proximity of residues in the EAA motifs of MalF and MalG to MalK was further confirmed through crosslinking experiments (215). The hypothesis that the EAA motif constitutes a site of interaction between the IM proteins and the conserved ABC modules (89, 244) is clearly proven correct by structural studies (205,285,343,366).…”

Section: Bpd Uptake Systemsmentioning

confidence: 54%

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

Davidson

Dassa

Orelle

et al. 2008

Microbiol Mol Biol Rev

1,185

1,137

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SUMMARY ATP-binding cassette (ABC) systems are universally distributed among living organisms and function in many different aspects of bacterial physiology. ABC transporters are best known for their role in the import of essential nutrients and the export of toxic molecules, but they can also mediate the transport of many other physiological substrates. In a classical transport reaction, two highly conserved ATP-binding domains or subunits couple the binding/hydrolysis of ATP to the translocation of particular substrates across the membrane, through interactions with membrane-spanning domains of the transporter. Variations on this basic theme involve soluble ABC ATP-binding proteins that couple ATP hydrolysis to nontransport processes, such as DNA repair and gene expression regulation. Insights into the structure, function, and mechanism of action of bacterial ABC proteins are reported, based on phylogenetic comparisons as well as classic biochemical and genetic approaches. The availability of an increasing number of high-resolution structures has provided a valuable framework for interpretation of recent studies, and realistic models have been proposed to explain how these fascinating molecular machines use complex dynamic processes to fulfill their numerous biological functions. These advances are also important for elucidating the mechanism of action of eukaryotic ABC proteins, because functional defects in many of them are responsible for severe human inherited diseases.

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Section: Bpd Uptake Systemsmentioning

confidence: 54%

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

Davidson

Dassa

Orelle

et al. 2008

Microbiol Mol Biol Rev

1,185

1,137

View full text Add to dashboard Cite

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“…This notion is further supported by the following experimental evidence; when mutated to phenylalanine the residue immediately succeeding Ala-85 in MalK, Leu-86 causes a defective transport complex. Biochemical analysis revealed that the purified variant exhibits ATPase activity comparable to wild type, whereas the transport complex containing the mutant MalK fails to hydrolyze ATP in the presence of maltose-loaded binding protein (38). Thus, the mutation is likely to interrupt the signaling pathway by preventing activation of the ATPase activity of the MalK subunits.…”

Section: V114c and V117c Formed Cross-links Only With Malf(s3c)/malg(ϫ)-mentioning

confidence: 99%

ATP Modulates Subunit-Subunit Interactions in an ATP-binding Cassette Transporter (MalFGK2) Determined by Site-directed Chemical Cross-linking

Hunke¹,

Mourez²,

Jéhanno³

et al. 2000

Journal of Biological Chemistry

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“…Other candidate residues for which conformational changes have been demonstrated are located in the helical subdomain of MalK (24,31) and in the LSGGQ motif (32).…”

mentioning

confidence: 99%

ATP Induces Conformational Changes of Periplasmic Loop Regions of the Maltose ATP-binding Cassette Transporter

Daus

Landmesser

Schlösser

et al. 2006

Journal of Biological Chemistry

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We have studied cofactor-induced conformational changes of the maltose ATP-binding cassette transporter by employing limited proteolysis in detergent solution. The transport complex consists of one copy each of the transmembrane subunits, MalF and MalG, and of two copies of the nucleotide-binding subunit, MalK. Transport activity further requires the periplasmic maltose-binding protein, MalE. Binding of ATP to the MalK subunits increased the susceptibility of two tryptic cleavage sites in the periplasmic loops P2 of MalF and P1 of MalG, respectively. Lys 262 of MalF and Arg 73 of MalG were identified as probable cleavage sites, resulting in two N-terminal peptide fragments of 29 and 8 kDa, respectively. Trapping the complex in the transition state by vanadate further stabilized the fragments. In contrast, the tryptic cleavage profile of MalK remained largely unchanged. ATP-induced conformational changes of MalF-P2 and MalG-P1 were supported by fluorescence spectroscopy of complex variants labeled with 2-(4-maleimidoanilino)naphthalene-6-sulfonic acid. Limited proteolysis was subsequently used as a tool to study the consequences of mutations on the transport cycle. The results suggest that complex variants exhibiting a binding protein-independent phenotype (MalF500) or containing a mutation that affects the "catalytic carboxylate" (MalKE159Q) reside in a transition state-like conformation. A similar conclusion was drawn for a complex containing a replacement of MalKQ140 in the signature sequence by leucine, whereas substitution of lysine for Gln 140 appears to lock the transport complex in the ground state. Together, our data provide the first evidence for conformational changes of the transmembrane subunits of an ATPbinding cassette import system upon binding of ATP. ATP-binding cassette (ABC)3 proteins exist in all living organisms and form one of the largest superfamilies. They are integral to almost every biological process and physiological system. Most are involved in the uptake or export of an enormous variety of substances across cell membranes, from small ions to large polypeptides. Many of these proteins are of considerable medical importance. Mutations in several "ABC genes" lead to genetic diseases, such as cystic fibrosis, Tangier disease, and adrenoleukodystrophy, or confer resistance to antibiotics and chemotherapeutic agents (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 prokaryotes, these domains are mostly expressed as separate protein subunits, whereas in eukaryotes, especially in mammalian cells, they are usually fused into a single polypeptide chain.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 (2). To date, the crystal structures of several mostly prokaryotic ABC domains have been reported (reviewed i...

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Novel Missense Mutations That Affect the Transport Function of MalK, the ATP-Binding-Cassette Subunit of the Salmonella enterica Serovar Typhimurium Maltose Transport System

Cited by 24 publications

References 21 publications

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

ATP Modulates Subunit-Subunit Interactions in an ATP-binding Cassette Transporter (MalFGK2) Determined by Site-directed Chemical Cross-linking

ATP Induces Conformational Changes of Periplasmic Loop Regions of the Maltose ATP-binding Cassette Transporter

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