Cryo-EM is setting records in membrane protein structural biology.
It's raising standards, too.

2018 is already a record breaking year in membrane protein structure determination, and we’re barely three quarters through.  As of the 9/12/2018 update to the PDB, there have been 83 unique membrane protein structures deposited in 2018, which is on pace to be the most ever in a single year(1,2).  The previous record was 84 in 2016.  Of these structures, 43 (52%) have been determined using single particle electron cryo-microscopy (Cryo-EM), another record!  The previous amount of unique membrane protein structures determined by Cryo-EM was 33 in 2017, again showing the profound effect this method is having on protein structural biology. 


Interestingly, over 55% of these unique membrane protein structures determined by Cryo-EM are ion channels, the majority of which (28%) belonging to the TRP channel family. These TRP channel structures include: TRPV3(3), TRPM7(4), PDK2L1(5), TRPM2(6), and TRPC3(7) among others. 

Like we’ve done in the fall of 2017 and 2016 , we want to provide an update on the most recent structures of membrane proteins determined by Cryo-EM, and the detergents used in those experiments.  As in previous years, we’re still seeing detergents such as Digitonin, GDN, DDM, DDM+CHS, and LMNG being commonly used for Cryo-EM experiments, along with non-detergent systems such as Amphipol A8-35, Amphipol PMAL-C8, and lipid nanodiscs.

Tools for Cryo-EM:
Anatrace and Molecular Dimensions are continually developing tools and reagents to support the membrane and soluble protein Cryo-EM workflow.  These include our fluorinated surfactants to improve vitrification, GDN, grid boxes, grid box storage pucks, and more. Check out our new Cryo-EM workflow page to learn more about all of the latest tools we have to support your Cryo-EM experiments!


Recent unique membrane protein structures determined by Cryo-EM (sorted by PDB release date)
PDB Release Date Name Ref. MW (kDa) Resolution (Å) Detergent
5YD1 9/12/18 OSCA 1.1 Channel 8 175 3.50 1% Digitonin
6DVW 9/5/18 TRPV3 TRP channel 3 363 4.30 0.5% Digitonin
6C70 8/22/18 ORCO receptor 9 214 3.50 0.5% Digitonin
6E10 8/22/18 PTEX Core Complex 10 1090 4.16 0.15% Triton X-100
5ZSU 8/15/18 LRRC8 anion channel 11 572 4.25 1% Digitonin
5ZX5 8/15/18 TRPM7 TRP Channel 4 440 3.30 Amphipol PMAL-C8
6DJB 8/15/18 SWELL1 (LRRC8A) anion channel 12 566 4.40 0.5% Digitonin
6DW0 8/8/18 α1b1γ1 GABAA receptor 13 243 3.80 1 mM DDM
6CJQ 8/1/18 CNG K+ channel SthK 14 222 3.42 Lipid Nanodiscs
6DQJ 8/1/18 InsP3R3 receptor 15 1218 3.49 0.6% Digitonin
6DU8 7/25/18 PKD2L1 TRP Channel 5 369 3.11 Amphipol PMAL-C8
6GY6 7/25/18 XaxAB pore complex 16 1118 4.00 Amphipol A8-35
6D7W 7/11/18 Mitochondrial calcium uniporter 17 192 3.80 Saposin / E. coli Lipids
6DMB 7/11/18 Patched1 (Ptch1) 18 153 3.90 0.6% Digitonin
6DNF 7/11/18 Mitochondrial calcium uniporter 19 165 3.20 0.5 mM Digitonin
6DT0 7/11/18 Mitochondrial calcium uniporter 20 212 3.70 Amphipol PMAL-C8
5ZJI 6/20/18 Photosystem I w/ LHC I & II 21 748 3.30 Digitonin/α-DDM
6COY 6/13/18 Human CLC-1 ion channel 22 218 3.36 0.04%/0.004% DDM:CHS
6GCT 6/13/18 ASCT2 Transporter 23 170 3.85 0.05%/0.005% DDM:CHS
6G2J 6/6/18 Respiratory Complex I 24 1066 3.30 0.5% DDM
6CFW 5/23/18 Ancient respiratory system 25 293 3.70 0.3% DDM
6CO7 5/16/18 TRPM2 TRP channel 6 753 3.07 0.06% Digitonin
6CUD 5/16/18 TRPC3 TRP channel 7 374 3.30 1% Digitonin
6G9O 5/16/18 LRRC8A anion channel 26 565 4.25 1.2% Digitonin
6BTM 5/9/18 Alternative complex III 27 301 3.40 3:1 SMA
6F0K 5/9/18 Alternative complex III 28 316 3.87 0.5% DDM
5YQ7 5/2/18 RC-LH Core Complex 29 334 4.10 0.2% DDM
6G1K 5/2/18 TRPC4 TRP Channel 30 427 3.60 Amphipol A8-35
 
 
 

References:
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  2. RCSB Protein Data Bank.  Accessed 09/12/2017: http://www.rcsb.org/pdb/.
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