A common interface on histidine-containing phosphocarrier protein for interaction with its partner proteins

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• The phosphoenolpyruvate:sugar phosphotransferase system (PTS) is crucial for bacterial sugar uptake and regulation.
• Histidine-containing phosphocarrier protein (HPr) is a key component of the PTS, involved in phosphoryl group transfer and allosteric regulation.
• The specific interaction surfaces of HPr with its various protein partners were previously uncharacterized.

Purpose of the Study:

• To identify and characterize the binding interfaces of HPr with its interacting proteins in Escherichia coli.
• To understand the molecular basis of HPr's multifaceted roles in bacterial physiology.

Main Methods:

• Utilized nuclear magnetic resonance (NMR) spectroscopy to study interactions.
• Employed uniformly 15N-labeled HPr and determined chemical shift changes upon binding to glycogen phosphorylase, glucose-specific enzyme IIA, and the N-terminal domain of enzyme I.
• Mapped NMR chemical shift perturbations onto the 3D structure of HPr.

Main Results:

• Identified specific binding surfaces on HPr for glycogen phosphorylase, enzyme IIA, and enzyme I.
• Demonstrated that HPr utilizes remarkably similar surfaces for interacting with these diverse partners.
• Provided a structural basis for HPr's role in phosphoryl transfer and allosteric regulation.

Conclusions:

• HPr employs a conserved interaction surface to bind multiple protein partners.
• This conserved interface facilitates HPr's central role in the bacterial PTS and cellular regulation.
• The findings offer insights into the adaptability and efficiency of bacterial signaling systems.