Periplasmic Binding Protein Dimer Has a Second Allosteric Event Tied to Ligand Binding

Autor: Le Li, Sarah L Lucas, Edward Wright, Dean A. A. Myles, Sudipa Ghimire-Rijal, Christopher B. Stanley, Matthew J. Cuneo, Pratul K. Agarwal
Rok vydání: 2017
Předmět:
Zdroj: Biochemistry. 56:5328-5337
ISSN: 1520-4995
0006-2960
DOI: 10.1021/acs.biochem.7b00657
Popis: The ligand-induced conformational changes of periplasmic binding proteins (PBP) play a key role in the acquisition of metabolites in ATP binding cassette (ABC) transport systems. This conformational change allows for differential recognition of the ligand occupancy of the PBP by the ABC transporter. This minimizes futile ATP hydrolysis in the transporter, a phenomenon in which ATP hydrolysis is not coupled to metabolite transport. In many systems, the PBP conformational change is insufficient at eliminating futile ATP hydrolysis. Here we identify an additional state of the PBP that is also allosterically regulated by the ligand. Ligand binding to the homodimeric apo PBP leads to a tightening of the interface α-helices so that the hydrogen bonding pattern shifts to that of a 310 helix, in-turn altering the contacts and the dynamics of the protein interface so that the monomer exists in the presence of ligand.
Databáze: OpenAIRE