Alternatives to Styrene‐ and Diisobutylene‐Based Copolymers for Membrane Protein Solubilization via Nanodisc Formation

Abstract

Styrene‐maleic acid copolymers (SMAs), and related amphiphilic copolymers, are promising tools for isolating and studying integral membrane proteins in a native‐like state. However, they do not exhibit this ability universally, as several reports have found that SMAs and related amphiphilic copolymers show little to no efficiency when extracting specific membrane proteins. Recently, it was discovered that esterified SMAs could enhance the selective extraction of trimeric Photosystem I from the thylakoid membranes of the thermophilic cyanobacteria; however, these polymers are susceptible to saponification that can result from harsh preparation or storage conditions. To address this concern, we herein describe the development of α‐olefin‐maleic acid copolymers (αMAs) that can extract trimeric PSI from cyanobacterial membranes with the highest extraction efficiencies observed when using any amphiphilic copolymers, including diisobutylene‐co‐maleic acid (DIBMA) and functionalized SMA samples. Furthermore, we will show that αMAs facilitate the formation of photosystem I‐containing nanodiscs that retain an annulus of native lipids and a native‐like activity. We also highlight how αMAs provide an agile, tailorable synthetic platform that enables fine‐tuning hydrophobicity, controllable molar mass, and consistent monomer incorporation while overcoming shortcomings of prior amphiphilic copolymers.

A proteome-wide quantitative platform for nanoscale spatially resolved extraction of membrane proteins into native nanodiscs

“…Secondly, it is essen�al to have proteome-scale high-throughput resources and pla�orms that can rapidly deliver the most op�mized extrac�on efficiency for target MPs as exis�ng protocols are extremely low throughput. Moreover, the prolifera�on of various polymers claiming to form na�ve nanodiscs, with many commercially available and others proposed as suitable candidates, adds complexity to the process of iden�fying the most appropriate chemical condi�ons for a target MP extrac�on [17][18][19][20][21] . This makes the en�re process both very low throughput and costly.…”