Analysis of Bacterial Polyphosphate Granules

Our experts have a keen interest in the study of liquid-liquid and liquid-solid phase transitions in bacterial cells. We have cutting-edge super-resolution imaging or infinite diffraction microscopy apparently combined with single molecule trafficking methods, and computer analysis platforms to analyze key microbial biomolecular condensates undergoing LLPS, as well as the formation and organization of biomolecular condensates within the intracellular space. Here, CD BioSciences is committed to analyzing intrinsically disordered bacterial polyphosphate (polyP) granules.

Introduction of Bacterial Polyphosphate Granules

Polyphosphates (polyPs) are simple and energy-rich polyanions composed of phosphate anhydride bonded phosphates that are commonly found in organisms ranging from bacteria to mammals. They have a wide range of biological functions, including metal chelation, base buffering, energy storage, osmolarity regulation, stress response, and enhanced biological phosphate removal, etc. Bacterial polyP is a long chain of hundreds of phosphate units. Interest in polyP has recently surged following the discovery that polyP transfer to proteins is a post-translational modification and that polyP regulates protein folding and misfolding in cells. The polyP granules are an important candidate for bacterial phase separation and are present in bacteria under stress and starvation conditions.

Fig. 1. Schematic of the proposed polyP structures in X. autotrophicus granules. (Mandala VS, et al., 2020)

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PolyP granule biogenesis is an ancient and ubiquitous starvation response in bacteria. Although the ability to make polyP is important for survival during quiescence and resistance to various environmental stresses, little is known about granulogenesis. In addition, the chemical simplicity of polyP makes it difficult to verify true binding interactions. Our laboratory has quantitative microscopy at the high spatial and temporal resolution to analyze polyP particles in bacteria starved of carbon, nitrogen, phosphate, and amino acids.

CD BioSciences offers specialized services to analyze the structural dynamics and biochemical functions of bacterial intrinsically disordered polyP granules. Our technology platforms are as follows:

• We offer transmission electron microscopy (TEM) for imaging polyP granules in immobilized cells.
• Our technical team can use a combination of cryo- and conventional electron microscopy without fixed and light microscopy, and combine genetic and spectroscopic techniques to quantitatively characterize the kinetics of polyP nucleation and growth at high spatial and temporal resolution.
• We establish the human opportunistic pathogen P. aeruginosa as a model organism to characterize the liquid-liquid phase separation (LLPS) of polyP granules. We also provide nitrogen limitation as a model stress condition to study polyP granule biogenesis.
• Our experts are committed to developing therapeutic PolyP targets to provide alternative or adjunctive therapies to help combat bacterial infections and their inflammatory complications.

Why We Choose P. aeruginosa to Characterize Bacterial PolyP Granules?

(1) Unlike some bacteria, including C. crescentus and Campylobacter jejuni, which are thought to produce polyP particles even during exponential growth, P. aeruginosa conditionally produces polyP granules, facilitating the observation of ab initio particle formation.

(2) With the exception of E. coli, P. aeruginosa is the organism with the most detailed biochemical characterization of the mechanism of polyP biosynthesis and quantification of polyP granules under various starvation states.

CD BioSciences offers a simple modular biomolecular platform to characterize the LLPS of intrinsically disordered polyP granules. We aim to characterize the process of polyP granule biosynthesis and analyze its function in the cell cycle exit of P. aeruginosa. If you have any special requirements for our services, please feel free to contact us.