Crystallizationofmembraneproteinsisachallengingundertakingandanumberofalternativetechniqueshavebeendevelopedsuchaslipidiccubicphaseandbicellecrystallization.Bothofthesetechniquesallowforthereconstitutionofadetergentsolubilizedmembraneproteininalipidicenvironment,andtheproteinstendtopackintotype-Icrystals.Bicellesareformedfromamixtureof1,2-dimyristoyl-sn-glycero-3-phosphocholine(DMPC,D514)and1,2-dihexanoyl-sn-glycero-3-phosphocholine(DHPC,D606)oramixtureofDMPCand3-((3-cholamidopropyl)dimethylammonio)-2-hydroxy-1-propanesulfonate(CHAPSO,C317).Bicellesarebilayerdiscswiththebilayerformedbythelipid(DMPC)andthedetergent(DHPCorCHAPSO)coveringtheedgesofthehydrophobicbilayer.
 
Settingupacrystallizationtrialinbicellescanbedonewithfoursimplesteps:

• Preparationofthebicellemedium
• Incorporationoftheproteinintobicelles
• Setupofcrystallizationtrials
• Monitoring,harvesting,anddatacollectionofcrystals

Tosimplifythisprocess,Anatraceofferspremixedbicellesolutions.Thesesolutionscontain0.25mlofa30%solutionofeitherDMPC:CHAPSOorDMPC:DHPCbicellesata2.8:1ratio.Forinitialcrystallizationscreening,werecommendscreeningbetween5%-8%bicelles.Toreconstituteaproteinintobicelles,proteinismixedwiththebicellesolutionina4:1ratio.Forexample,tocreate100 µlofa5%protein-bicellemixture,the30% stockbicellesolutionisfirstdilutedwithH₂Oto25%(16.7µl30%bicelles+3.3µlH₂O=20 µl25%bicelles),and then addedto80 µlofconcentratedproteinsolution.The reconstitutedproteininbicellescanthenbeusedtosetupcrystallizationexperimentsineitherhangingdrop,sittingdrop,ortheMicrolyticCrystalFormerplates.AfullprotocolforproteinreconstitutionandcrystallizationisbeavailableundertheTechnicalDocumentationtab.

Note:Bicellesareshippedatroomtemperature.Storeat-20^oCuponreceiving. 

Citations:
1.) Faham,S.andBowie,J.U.(2002) J. Mol.Biol. 316(1), 1-6.
2.) Poulos,S. etal. (2015) MethodsinEnzymology 557, 393-416.
3.) Kimble-Hill,A.C.(2013) Front.Biol. 8(3), 261-272.
4.) Agah,S.andFaham,S.(2012) MethodsinMolecularBIOLOGy 914,3-16.