Sensing Enzyme Activation Heat Capacity at the Single-Molecule Level Using Gold-Nanorod-Based Optical Whispering Gallery Modes.

Here, we report a label-free gold nanoparticle-based single-molecule optical platform to study the immobilization, activity, and thermodynamics of single enzymes. The sensor uses plasmonic gold nanoparticles coupled to optical whispering gallery modes (WGMs) to probe enzyme conformational dynamics during turnover at a microsecond time resolution. Using a glucosidase enzyme as the model system, we explore the temperature dependence of the enzyme turnover at the single-molecule (SM) level.

Whispering-gallery mode (WGM) sensors: review of established and WGM-based techniques to study protein conformational dynamics.

Monitoring the conformational dynamics of proteins is crucial for a better understanding of their biological functions. To observe the structural dynamics of proteins, it is often necessary to study each molecule individually. To this end, single-molecule techniques have been developed such as Förster resonance energy transfer and optical tweezers.

The Culture Environment Influences Both Gene Regulation and Phenotypic Heterogeneity in .

Microorganisms shape the composition of the medium they are growing in, which in turn has profound consequences on the reprogramming of the population gene-expression profile. In this paper, we investigate the progressive changes in pH and sugar availability in the medium of a growing () culture. We show how these changes have an effect on both the cellular heterogeneity within the microbial community and the gene-expression profile of the microbial population.