Substrate Transport Activation Is Mediated through Second Periplasmic Loop of Transmembrane Protein MalF in Maltose Transport Complex of Escherichia coli
| Autor: | Bernd Rupp, Bernd Reif, Erwin Schneider, Tomas Jacso |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Monosaccharide Transport Proteins
Biological Transport Active ATP-binding cassette transporter Biology Biochemistry Protein Structure Secondary Substrate Specificity chemistry.chemical_compound ATP hydrolysis Escherichia coli Binding site Maltose Molecular Biology Binding Sites Escherichia coli Proteins Substrate (chemistry) Cell Biology Periplasmic space Transmembrane protein chemistry Solvent-PRE NMR Membrane Proteins Residual Dipolar Couplings Receptor Structure-Function ABC Transporter Structural Biology Biophysics ATP-Binding Cassette Transporters Maltose transport complex Molecular Biophysics |
| Zdroj: | The journal of biological chemistry, 287(21): 17040-17049 J. Biol. Chem. 287, 17040-17049 (2012) |
| Popis: | In a recent study we described the second periplasmic loop P2 of the transmembrane protein MalF (MalF-P2) of the maltose ATP-binding cassette transporter (MalFGK(2)-E) as an important element in the recognition of substrate by the maltose-binding protein MalE. In this study, we focus on MalE and find that MalE undergoes a structural rearrangement after addition of MalF-P2. Analysis of residual dipolar couplings (RDCs) shows that binding of MalF-P2 induces a semiopen state of MalE in the presence and absence of maltose, whereas maltose is retained in the binding pocket. These data are in agreement with paramagnetic relaxation enhancement experiments. After addition of MalF-P2, an increased solvent accessibility for residues in the vicinity of the maltose-binding site of MalE is observed. MalF-P2 is thus not only responsible for substrate recognition, but also directly involved in activation of substrate transport. The observation that substrate-bound and substrate-free MalE in the presence of MalF-P2 adopts a similar semiopen state hints at the origin of the futile ATP hydrolysis of MalFGK(2)-E. |
| Databáze: | OpenAIRE |
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