Atropisomerism in a polyglutamate-based thermoresponsive alignment medium

Area of Science:

• Biophysical Chemistry
• Structural Biology
• Materials Science

Background:

• Structure elucidation using residual dipolar couplings (RDCs) is a powerful technique in chemistry and biology.
• RDCs require alignment media to orient molecules, which can be challenging to develop and utilize.
• Existing alignment media often provide limited data or require sample manipulation.

Purpose of the Study:

• To develop a novel alignment medium for RDC measurements.
• To investigate the utility of temperature-dependent atropisomerism in alignment media.
• To enable the acquisition of multiple RDC datasets from a single sample.

Main Methods:

• Synthesis and characterization of poly-γ-p-biphenyl(2'-methoxy-2-methyl)methyl-L-glutamate (PBPM³LG).
• Preparation of lyotropic liquid crystals (LLCs) using PBPM³LG.
• Acquisition of RDC data at various temperatures to probe atropisomerism.

Main Results:

• PBPM³LG forms stable LLCs suitable for molecular alignment.
• Temperature-dependent atropisomerism within the biphenyl group of PBPM³LG was observed.
• Multiple RDC datasets were successfully acquired from a single sample by varying temperature.

Conclusions:

• Lyotropic liquid crystals derived from PBPM³LG serve as effective alignment media for RDCs.
• Temperature-controlled atropisomerism offers a novel strategy to obtain diverse RDC information from one sample.
• This approach enhances the efficiency and scope of structure elucidation using RDCs.