scholarly journals Role of Denaturation in Maltose Binding Protein Translocation Dynamics

2012 ◽  
Vol 116 (14) ◽  
pp. 4255-4262 ◽  
Author(s):  
Marco Bacci ◽  
Mauro Chinappi ◽  
Carlo Massimo Casciola ◽  
Fabio Cecconi
Keyword(s):  
Protein Translocation ◽  
Binding Protein ◽  
Maltose Binding Protein

scholarly journals Exploring the Role of Integral Membrane Proteins in ATP-Binding Cassette Transporters: Analysis of a Collection of MalG Insertion Mutants

1998 ◽  
Vol 180 (9) ◽  
pp. 2507-2514 ◽  
Author(s):  
Bryn D. Nelson ◽  
Beth Traxler
Keyword(s):  
Membrane Proteins ◽  
Cytoplasmic Membrane ◽  
Binding Protein ◽  
Maltose Binding Protein ◽  
Integral Membrane Proteins ◽  
Atp Binding ◽  
Mutant Proteins ◽  
Transport Complex ◽  
Atp Binding Cassette

ABSTRACT The maltose transport complex of Escherichia coli is a well-studied example of an ATP-binding cassette transporter. The complex, containing one copy each of the integral membrane proteins MalG and MalF and two copies of the peripheral cytoplasmic membrane protein MalK, interacts with the periplasmic maltose-binding protein to efficiently translocate maltose and maltodextrins across the bacterial cytoplasmic membrane. To investigate the role of MalG both in MalFGK2 assembly interactions and in subsequent transport interactions, we isolated and characterized 18 different MalG mutants, each containing a 31-residue insertion in the protein. Eight insertions mapping to distinct hydrophilic regions of MalG permitted either assembly or both assembly and transport interactions to occur. In particular, we isolated two insertions mapping to extracytoplasmic (periplasmic) regions of MalG which preserved both assembly and transport abilities, suggesting that these are permissive sites in the protein. Another periplasmic insertion seems to affect only transport-specific interactions between MalG and maltose-binding protein, defining a novel class of MalG mutants. Finally, four MalG mutant proteins, although stably expressed, are unable to assemble into the MalFGK2 complex. These mutants contain insertions in only two different hydrophilic regions of MalG, consistent with the notion that a restricted number of domains in this protein are critical complex assembly determinants. These MalG mutants will allow us to further explore the intermolecular interactions of this model transporter.

Genetic approach to the role of tryptophan residues in the activities and fluorescence of a bacterial periplasmic maltose-binding protein

1990 ◽  
Vol 214 (1) ◽  
pp. 337-350 ◽  
Author(s):  
Pierre Martineau ◽  
Sevec Szmelcman ◽  
John C. Spurlino ◽  
Florente A. Quiocho ◽  
Maurice Hofnung
Keyword(s):  
Binding Protein ◽  
Maltose Binding Protein ◽  
Genetic Approach ◽  
Tryptophan Residues
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