Structure of a bacterial energy-coupling factor transporter

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Energy-coupling factor (ECF) transporters are conserved prokaryotic membrane proteins.
• They share domain organization with ATP-binding cassette (ABC) transporters.
• The quaternary structure and transport mechanism of ECF transporters are largely unknown.

Purpose of the Study:

• To determine the crystal structure of a nucleotide-free ECF transporter.
• To elucidate the structural basis of ECF transporter function.
• To propose a working model for the ECF transporter mechanism.

Main Methods:

• X-ray crystallography was used to determine the structure.
• The structure was solved at a resolution of 3.5 Å.
• Bioinformatics and structural analysis were employed.

Main Results:

• The crystal structure of a Lactobacillus brevis ECF transporter was determined.
• The T component exhibits a horseshoe-shaped architecture with transmembrane and cytoplasmic helices.
• The S component is bound horizontally by the T component's transmembrane and cytoplasmic helices.

Conclusions:

• The determined structure provides insights into the ECF transporter architecture.
• The findings suggest a plausible working model for the ECF transporter mechanism.
• This study advances the understanding of prokaryotic membrane transport systems.