Commercial SMA Polymers

The discovery that copolymers composed of styrene and maleic acid groups can solubilize native lipid:protein complexes direct from cells or raw membrane has stimulated a flurry of new research.

Polyscience, powered by Polyscope Polymers from the Netherlands is an official sponsor of the SMALP network. After supplying the community with three types of SMA products for membrane protein solubilization for years, these polymers have now been commercialized as SMALP products that are available from Polyscience.

These products have been widely used and are recommended to test and optimize purification of membrane proteins along with bound lipids and partner proteins. A ratio of styrene to maleic acid of around 2:1 is generally most recommended.

Product S:MA Ratio† Mw† (g/mole) Source
SMALP 25010P 3:1 10000 Polyscience
SMALP 30010P 2.3:1 6500 Polyscience
SMALP 40005P 1.2:1 5000 Polyscience

Contact Polyscience for ordering SMALP 30010P, 25010P and 40005P reagents for your research. These products are provided as ready-to-use solutions for membrane solubilization. Detailed product information can be found in the technical data sheet and will be provided in the certificate of analysis (CoA) supplied with your order.

Other SMA polymers that are commercially available are below.

Product S:MA Ratio† Mw† (g/mole) Source
Lipodisq L8920 2:1 n/a Sigma
Lipodisq L9045 3:1 n/a Sigma
Lipodisq L9170 3:1 n/a Sigma

† The SMA copolymers are defined by the average ratio of styrene to maleic acid repeat units (S:MA). The lengths and blockiness of the polymers is different for each. The number average molecular weight (Mn) is total weight of the polymer molecules divided by the number of molecules. The weight average molecular weight (Mw) is more sensitive to the larger chains present. The polydispersity index (PDI) equals Mw/Mn and is a measure of distribution of the molecular weights.

Commercial non-SMA polymers that form discs

In addition to SMA polymers, related synthetic copolymers convert membranes into discs and are listed below.

Product Subunit Ratio† Mw† (g/mole) Mn† (g/mole) Source
DIBMA 1:1 15300 8400 Anatrace
DIBMA lyophilized HEPES or TRIS ready to use 1:1 10,000 and 12,000   Cube Biotech
PMA 1:1.1 n/a n/a Avanti
Sokalan CP9 1:1 15300 8400 BASF

¶ PMA refers to polymethacrylate copolymer product "N−C4−52−6.9" from Avanti. This belongs to the family of polymers referred to in Yasuhara K, Arakida J, Ravula T, Ramadugu SK, Sahoo B, Kikuchi JI, Ramamoorthy A. 2017. Spontaneous Lipid Nanodisc Fomation by Amphiphilic Polymethacrylate Copolymers. J Am Chem Soc. 139(51):18657-18663.

Anatrace launched their version of purified DIBMA based upon the work of Sandro Keller, and Cube Biotech is offering ready to use DIBMA products in two buffer systems as well as protocols and services. Sokalan CP9 is the tradename of an alternating copolymer of maleic acid and diisobutylene (2,4,4-trimethylpent-1-ene) (DIBMA). Sandro Keller's slides and the 2016 paper by AO Oluwole et. al. on DIBMA show that it is well-suited to solubilizing larger membrane proteins. It is also compatible with UV and CD experiments and higher levels of divalent cations such as calcium and magnesium.

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