TY - JOUR
T1 - Solubilisation & purification of membrane proteins using benzylamine-modified SMA polymers
AU - Akram, Aneel
AU - Hadasha, Waled
AU - Kuyler, Gestél C.
AU - Smith, Michael-Phillip
AU - Bailey-Dallaway, Shauna
AU - Preedy, Aiden
AU - Browne, Caolan
AU - Broadbent, Luke
AU - Hill, Adam
AU - Javaid, Tahreem
AU - Nazar, Haroon
AU - Samra, Nikita
AU - Naveed, Anadil
AU - Tregunna, Holly
AU - Joshi, Hetal
AU - Akhtar, Nusheen
AU - Javed, Aneesa
AU - Bowater, Jessica
AU - Ravenhill, Joel
AU - Hajdu, Patrik
AU - Ali, Yazdan
AU - Tailor, Yanik
AU - Mumtaz, Sabreen
AU - Hamza, Mohammed
AU - Gill, Kiran
AU - Gillett, Jemma
AU - Patton, Faye
AU - Arshid, Huma
AU - Zaheer, Maria
AU - Qureshi, Hannah
AU - Edwards, Isabel
AU - Patel, Shreya
AU - Azadi, Aaminah
AU - Pollock, Naomi
AU - Kitchen, Philip
AU - Klumperman, Bert
AU - Rothnie, Alice j.
N1 - Copyright © 2024, The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
PY - 2025/1
Y1 - 2025/1
N2 - Extraction of proteins from the membrane using styrene maleic acid co-polymers (SMA), forming SMA lipid particles (SMALPs), has allowed for the first time the purification of membrane proteins with their lipid bilayer environment. To date, SMA2000 has been the most effective polymer used for this purpose, with a 2:1 ratio of styrene:maleic acid, and styrene and maleic acid moieties spread statistically throughout the chain. However, SMA2000 is a highly polydisperse polymer that contains an array of different polymer lengths and sequences. RAFT polymerisation offers much better control over the polymer length; however, homogeneous distribution of styrene and maleic acid throughout the polymer is difficult to achieve. Instead, here RAFT polymerisation was used to produce a 1:1 styrene:maleic anhydride polymer, which was then modified with benzylamine. This mimics the 2:1 hydrophobic:hydrophilic nature of SMA2000, while controlling the length and obtaining a homogeneous distribution of the hydrophobic moieties (styrene and N-benzylmaleimide). SMA-benzylamine (SMA-BA) polymers of three different lengths (2, 4, and 7 kDa) were all able to solubilise purified lipids, cellular membranes, and a range of specific proteins. However, the larger 7 kDa polymer solubilised membranes more slowly and less efficiently than the shorter polymers. This also affected the yield of purified protein obtained by affinity purification with this polymer. The smallest 2 kDa polymer solubilised membranes the fastest but appeared to offer less stability to the extracted proteins. The SMA-BA polymers were more sensitive to Mg2+ ions than SMA2000. SMA-BA 4 kDa was otherwise comparable to SMA2000 and even gave a higher degree of purity.
AB - Extraction of proteins from the membrane using styrene maleic acid co-polymers (SMA), forming SMA lipid particles (SMALPs), has allowed for the first time the purification of membrane proteins with their lipid bilayer environment. To date, SMA2000 has been the most effective polymer used for this purpose, with a 2:1 ratio of styrene:maleic acid, and styrene and maleic acid moieties spread statistically throughout the chain. However, SMA2000 is a highly polydisperse polymer that contains an array of different polymer lengths and sequences. RAFT polymerisation offers much better control over the polymer length; however, homogeneous distribution of styrene and maleic acid throughout the polymer is difficult to achieve. Instead, here RAFT polymerisation was used to produce a 1:1 styrene:maleic anhydride polymer, which was then modified with benzylamine. This mimics the 2:1 hydrophobic:hydrophilic nature of SMA2000, while controlling the length and obtaining a homogeneous distribution of the hydrophobic moieties (styrene and N-benzylmaleimide). SMA-benzylamine (SMA-BA) polymers of three different lengths (2, 4, and 7 kDa) were all able to solubilise purified lipids, cellular membranes, and a range of specific proteins. However, the larger 7 kDa polymer solubilised membranes more slowly and less efficiently than the shorter polymers. This also affected the yield of purified protein obtained by affinity purification with this polymer. The smallest 2 kDa polymer solubilised membranes the fastest but appeared to offer less stability to the extracted proteins. The SMA-BA polymers were more sensitive to Mg2+ ions than SMA2000. SMA-BA 4 kDa was otherwise comparable to SMA2000 and even gave a higher degree of purity.
KW - Atm1
KW - Detergent-free
KW - Mass photometry
KW - Nanoparticle
KW - SMALP
UR - https://linkinghub.elsevier.com/retrieve/pii/S0301462224001728
UR - http://www.scopus.com/inward/record.url?scp=85206875599&partnerID=8YFLogxK
U2 - 10.1016/j.bpc.2024.107343
DO - 10.1016/j.bpc.2024.107343
M3 - Article
SN - 0301-4622
VL - 316
JO - Biophysical Chemistry
JF - Biophysical Chemistry
M1 - 107343
ER -