Analysis of Bacterial Polar Organizing Protein Z

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 polar organizing protein Z (PopZ).

PopZ as a Bacterial Biomolecular Condensate

PopZ is a small acidic protein found in α-amastigotes. In the Alphaproteobacterium Caulobacter crescentus, PopZ is required for the polar localization of at least 11 different proteins. Among them, the ParA and ParB proteins interact directly with PopZ, which play an important role in the involvement of cell cycle regulation and chromosome segregation. Structural analysis of the N-terminal 133aa of PopZ shows that it is intrinsically disordered, suggesting that PopZ has a flexible structure, adopting different interfaces for each chaperone protein. Recently, fluorescence microscopy analysis showed that PopZ forms spherical morphological condensates in vitro and that the phase behavior of PopZ condensates is a function of protein and salt concentration.

Fig. 1. Uncoupling PopZ self-assembly from interactions with other proteins. (Holmes J A, et al., 2016)

Customized Services

The intrinsically disordered nature of bacterial PopZ is critical for its function in the regulation of spatial organization and bacterial cellular processes. Its ability to adopt multiple conformations and interact with a variety of binding partners provides the flexibility required for its multiple functions. CD BioSciences offers specialized services to analyze the structural dynamics and interactions of intrinsically disordered bacterial PopZ. Our services include:

• Structural Characterization of the Multi-Protein Binding Domain of PopZ
  Study of the first 133 amino acids of PopZ as intrinsically disordered41 and distinct from the C-terminal self-assembly domain. We provide 2D and 3D high-resolution solution NMR spectroscopy to determine the major conformational states of the 133 amino acids at the N-terminal end of PopZ.
• Characterization of PopZ Liquid-Liquid Phase Separation (LPPS) in Vivo and in Vitro
  To probe the dynamic behavior of PopZ, we can express fluorescently labeled PopZ in Caulobacter and human cells, and detect PopZ condensates into micron-sized cytoplasmic condensates by the fluorescence recovery after photobleaching (FRAP) technique. We have established human cells as an independent platform to study the LLPS behavior of PopZ.
• Modification of PopZ Material Properties
  We offer a variety of strategies to tailor the material properties of PopZ to meet customer needs, including the length of the intrinsically disordered region, the ratio of proline to acidic residues, and the distribution of acidic residues in the sequence, etc. We will determine the optimal emergent properties to maintain the adaptability required for viscous liquid PopZ condensates.

CD BioSciences offers a simple modular biomolecular platform to characterize the LLPS of the intrinsically disordered bacterial PopZ. We aim to help our clients understand and manipulate the underlying organizing principles of PopZ condensates, ultimately allowing disease modeling and developing new therapeutic approaches. If you have any special requirements for our services, please feel free to contact us.