Both maltose-binding protein and ATP are required for nucleotide-binding domain closure in the intact maltose ABC transporter. Proc Natl Acad Sci U S A 2008 Sep 02;105(35):12837-42
Date
08/30/2008Pubmed ID
18725638Pubmed Central ID
PMC2529024DOI
10.1073/pnas.0803799105Scopus ID
2-s2.0-51349104365 (requires institutional sign-in at Scopus site) 93 CitationsAbstract
The maltose transporter MalFGK(2) of Escherichia coli is a member of the ATP-binding cassette superfamily. A periplasmic maltose-binding protein (MBP) delivers maltose to MalFGK(2) and stimulates its ATPase activity. Site-directed spin labeling EPR spectroscopy was used to study the opening and closing of the nucleotide-binding interface of MalFGK(2) during the catalytic cycle. In the intact transporter, closure of the interface coincides not just with the binding of ATP, as seen with isolated nucleotide-binding domains, but requires both MBP and ATP, implying that MBP stimulates ATPase activity by promoting the closure of the nucleotide-binding interface. After ATP hydrolysis, with MgADP and MBP bound, the nucleotide-binding interface resides in a semi-open configuration distinct from the fully open configuration seen in the absence of any ligand. We propose that P(i) release coincides with the reorientation of transmembrane helices to an inward-facing conformation and the final step of maltose translocation into the cell.
Author List
Orelle C, Ayvaz T, Everly RM, Klug CS, Davidson ALAuthor
Candice S. Klug PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ATP-Binding Cassette TransportersAdenosine Triphosphatases
Adenosine Triphosphate
Adenylyl Imidodiphosphate
Binding Sites
Carrier Proteins
Catalysis
Dimerization
Electron Spin Resonance Spectroscopy
Escherichia coli
Escherichia coli Proteins
Ligands
Liposomes
Maltose
Maltose-Binding Proteins
Models, Molecular
Monosaccharide Transport Proteins
Mutant Proteins
Protein Structure, Tertiary
Spin Labels
