A supplement to: NIGMS 1R15GM144907-01A1 - Polymer-Lipid Particles investigated by Magnetic Resonance Spectroscopy

Miami University Oxford, Oxford OH

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Abstract

A supplement to: NIGMS 1R15GM144907-01A1 - Polymer-Lipid Particles investigated by Magnetic Resonance Spectroscopy In response to: PA-20-272 - Administrative Supplements to Existing NIH Grants and Cooperative Agreements (Parent Admin Supp Clinical Trial Optional) Funds are requested from NIGMS to obtain state of the art gel permeation chromatography (GPC) multi-angle light scattering (MALS) equipment to facilitate polymer analysis. Development of novel polymers is integral to NIGMS 1R15GM144907- 01A1, therefore having reliable methods for characterizing the polymers is essential to the project. Funds are being requested to obtain a TOSOH EcoSEC Elite including Refractive Index and LenS3 Multi-Angle Light Scattering Detector GPC MALS system capable of efficient and accurate polymer analysis to replace equipment that is from 2014. Project Summary/Abstract: Membrane proteins represent approximately 30% of all known proteins but only approximately 1% of solved protein structures. Despite recent advances in methods for membrane protein structural biology, knowledge about this important class of proteins lags behind their soluble counterparts. Membrane proteins are critical to numerous aspects of health, ranging from regulation cellular function and transport into and out of the cell, through to viral infections which use membrane proteins as part of the infection cycle. In almost 90% of newly developed and approved therapeutics, protein structural information was used to guide the development of the therapeutic molecules. Due to the limited and incomplete structural information on membrane proteins, the development of therapeutics and treatments that target membrane bound proteins is limited. A challenge in elucidating membrane protein structures is the lack of robust and appropriate lipid membrane mimetics. Existing membrane mimetics have limitations that can hinder membrane protein structural determination. This highlights an urgent need to develop lipid membrane mimetics which both provide a good approximation to the native lipid bilayer in terms of both structure and curvature, while also facilitating structural analysis of the membrane protein embedded in the mimetic. Yet polymer structure-function relationships are not well established for polymers that interact with lipids and membrane proteins. This project will use modern controlled polymer chemistry tools, to create a new class of polymers that will self-assemble with lipids. These self-assembled polymer-lipid systems will form well defined discs on the order of 10s of nanometers, giving lipid membrane mimetics suitable for the analysis of many membrane proteins. The advanced polymer chemistry techniques will enable fine tuning of polymer’s length, charges, and hydrophobicity. Polymer analysis through GPC MALS will give detailed information on the polymer’s properties, facilitation structure -function relationships between polymers and their self-assembled structures. Polymers will also be modified with spin-labels for electron paramagnetic resonance spectroscopy. Electron paramagnetic resonance spectroscopy methods will be used on polymers, lipids and membrane proteins modified with appropriate spin labels, providing insights into the local dynamics and proximities of the self-assembled polymer-lipid and polymer-lipid-membrane protein complexes. These insights can be used to guide the design of polymers for robust lipid membrane mimetics. Training and mentoring of undergraduate students as well as a graduate assistant will be a core feature of the proposed project. Undergraduate students will be integrated fully into the projects, including the polymer analysis, along with the graduate student, gaining skills in this field at the interface of materials science and biophysics.