Enhanced function conferred on low-abundance chemoreceptor Trg by a methyltransferase-docking site

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Escherichia coli utilizes chemoreceptors for nutrient sensing and directed movement.
• Chemoreceptors exist in high- and low-abundance classes with distinct functional properties.
• High-abundance receptors mediate efficient chemotaxis, adaptation, and flagellar motor control.

Purpose of the Study:

• To investigate the functional differences between high- and low-abundance chemoreceptors in E. coli.
• To identify the molecular determinants responsible for the superior chemotaxis of high-abundance receptors.
• To enhance the function of a low-abundance receptor by modifying its structure.

Main Methods:

• Comparative analysis of high- and low-abundance chemoreceptor function in Escherichia coli.
• Genetic modification of the low-abundance receptor Trg by appending the C-terminal residues of the high-abundance receptor Tsr.
• Assessment of methyl-accepting activity, flagellar rotation bias, and chemotaxis in spatial gradients.

Main Results:

• The low-abundance receptor Trg, when augmented with the final 19 residues of Tsr, acquired high-abundance receptor characteristics.
• This augmentation included the methyltransferase-binding pentapeptide NWETF, enhancing methylation and adaptational capacity.
• Functional improvements included a shift in flagellar rotation bias and significantly enhanced chemotaxis in spatial gradients.

Conclusions:

• The methyltransferase-binding pentapeptide (NWETF) at the C-terminus is critical for high-abundance chemoreceptor function.
• Enhanced methyl-accepting activity, mediated by this docking site, is the key determinant for efficient chemotaxis and adaptation.
• Modifying low-abundance receptors with this motif can confer improved chemotactic performance.