TheBCS(BasicChemicalSpace)ScreendevelopedattheStructuralGenomicConsortium(SGC),Oxfordhasanovelapproachtoscreening.PEGsaregroupedbymolecularweightandmixedtocreatefourPEGSmears(availabletopurchaseseparately).TheSmearscoverabroaderrangeofchemicalspacewhilereducingthenumberofPEGvariables.ThisproductistheFXpre-filledplateversionofthisproduct,containing96x100uL.

PEGisaneffectivecrystallizationagentduetoitsprotein-proteininteractionpromotingproperties.TheBIOLOGicalMacromolecularCrystallizationdatabaserecordsatleast20differentPEGcompoundsinfrequentuseasmacromolecularprecipitants.TheBCSScreenovercomestheimpracticalityofsamplingallPEGvarietiesthathasledtoafewvariantspredominatinginthemostcommonscreens(right).

ThebottomlineisthatintestsattheSGCwith191humanproteins,TheBCSScreenhada42%hitratewithonly96conditions.Manyoftheseproteinshadfailedtocrystallizeinotherscreens.

Thefirst24conditionsinTheBCSScreenformagridscreenofthefourPEGSmearsagainstpH(range4.5-9.5).Theremaining72conditionsconsistofasparsematrixscreeninwhichtheprecipitantisalwaysoneofthePEGSmearsbutwithavarietyofadditivesandbuffers.Theadditivesincludesomeofthemoreunusualcrystal-promotingagentssuchasrubidiumchloride(alsousefulforphasing)andammoniumnitrate.Morecommonadditivesincludingsodiumbromide(usefulforphasing)andglycerolarealsousedinthescreen.

Reference

Chaikuad,A,Knapp,SandvonDelft,K(2015).DefinedPEGsmearsasanalternativeapproachtoenhancethesearchforcrystallizationconditionsandcrystal-qualityimprovementinreducedscreens.ActaCrystallographicaF71:1627-1639.

Molecular Dimensions 来自 digital.library.unt.edu   喜欢 0 阅读量： 1 作者： Moss, H. H 摘要： This study attempts to calculate the areas of the cross section and diameter of the CH3 group, COOH group, the length of the carbon chain, and the longtiudinal distance between carbon atoms for each of the three acids. It also attempts to develop a method of measuring the effective diameter of molecules of gases. Equations for these terms as given by MacDougall and experiments were performed and the data applied to the equation. 关键词： carbon chain carbon atoms diameter of molecules of gases