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CD.ppt

CD

liweizheng2008
2011-05-24 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《CDppt》,可适用于工程科技领域

snlbjmueducnoursebiophysicscoverhtmCircularDichroismCD圆二色光谱什么是圆二色谱旋光色散谱圆二色谱在生物,医学研究中的应用产生,特征,structureofmembraneproteinstructureofmembraneproteinCrystalStructureofMitochondrialRespiratoryMembraneProteinComplexIICell,,这是二十五年以来我国科学家完全立足于“本土”第一次在该杂志上发表完整的、系统性的、原创性研究成果hybridorbitalChiralLalanineDalanineXY线偏振光XYXY频率相同,方向相反振幅相同,相位相同线偏振光参照面频率相同,方向相反振幅相同、相位不同线偏振光参照面yy’axx’RL=tg(|El–Er|)(ElEr)椭圆偏振光频率相同,方向相反振幅不同、相位不同参照面左、右旋圆偏振光的合成椭圆偏振光OpticallyActiveSampleChiralRightandLefthandcircularlypolarizedlightPreferentialabsorptionoflefthandpolarized振动方程Ex=Excos(ωtφ)Ex=Excosω(tLv)φ波动方程Ex=Eoxcosωt(Lλ)nφOrCD(circulardichroism)与振幅A=lgII=(,)lnII=ελCLBeerLanmbertLaw=tg(|El–Er|)(ElEr)λ=Aλ(弧度)ΔAλ=AlAr=ΔελCLLOpticalactiveobjectEx=Excosωt(Lλ)nφC:摩尔浓度L:光程(dm)l:deg•mol•cmordeg•cm•dmol摩尔椭圆率l(themolarellipticity)lMRw=MRwylyl(thespecificellipticity)平均残基椭圆率lMRw(themeanresidueellipticity)l=Mwyll=λCL旋光色散与位相旋光色散与位相旋光色散ORD(opticalrotatorydispersion)nlnrChiralOpticalactiveobject=(λ)nDn=nlnra=f(l),弧度ΔΦ=(λ)ΔnLa=λLC圆双折射(Circularbirefringence):Ex=Excosωt(Lλ)nφ平均残基旋光度ml(themeanresiduerotation)ml=alMRwC:gmLL:dmMw:molecularweightMRw:themeanresidueMwl(thespecificrotation)摩尔比旋光度jl(themolarrotation)jl=alMwyl=lCwL基本原理(principle)Plane(linearly)polarizedlight基本原理(principle)RightandLefthandcircularlypolarizedlightOpticallyActiveSamplePreferentialabsorptionoflefthandpolarizedChiralEx=Excosωt(lλ)nφLightnl,nryy’axx’RLl=f(l)al=f(l)ORDCDKronigKramerstransitionrelationshipbetweenCDandORDandCottoneffectCottoneffectlellPositivecottoneffectNegativecottoneffectλλλInstrumenthttp:wwwstructurellnlgovCDofaminoacidandpeptidesAminoacid吲哚基酚羟基苯基二硫键咪唑基羧基。酪氨酸色氨酸苯丙氨酸胱氨酸脯氨酸在近紫外区(nm)对CD谱有贡献羧基在nm显示正峰。在波长大于nm的区域包括可见区域对CD谱的贡献主要来自像血红素一类含有金属离子的生色团这一波段CD谱常用于研究金属离子的氧化态、配位体以及链链相互作用。含有金属离子的生色团Secondarystructureofmacromoleculeahelixahelix:nm()nm,nm()bsheet:nm()antiparallel:redshiftparallel:blueshiftnm()bsheetUnorderedstructure:()belownm()nmweakbandunorderedbturn:nm()nm()nm()band,weakredshiftFarUV(nm)Contentofsecondarystructureθλ,α、θλ,β、θλ,γ分别为α螺旋、β折叠和非周期结构在波长λ处的椭圆率值fα、fβ、fγ分别为α螺旋、β折叠和非周期结构在蛋白质中所占重量百分比。图:三种LRR(lysinerichrepeat)家族肽的CD谱利用CD谱研究蛋白质的构象变化TFEUnfoldingfoldingnmnmConformationalvariesnm图A,Bob()和OctDNA复合物的CD谱蛋白质蛋白质、蛋白质核酸结合的研究克山病区粮饲养的豚鼠心肌线粒体膜的研究模型动物心肌线粒体膜的CD谱(a:病区粮喂养组b:病区粮补加蔬菜喂养组c:正常对照组)模型动物心肌线粒体细胞色素C氧化酶的CD谱(a:病区粮喂养组周前死亡b:病区粮喂养组存活的c:正常对照组)烟草花叶病毒侵染膜蛋白磷脂膜诱导的蜂毒素二级结构的变化蜂毒素的CD谱:蜂毒素插入单层膜的CD谱:蜂毒素吸附在单层膜上时的CD谱:在TrisHCL缓冲液中的蜂毒素CD谱α螺旋β折叠无规卷曲α螺旋β折叠无规卷曲NearUVspectra:toinvestigatethetertiarystructureProteinConcentration:mgmlCellPathLength:mmStabilizers(Metalions,etc):minimumBufferConcentration:mMoraslowaspossiblewhilemaintainingproteinstabilityTypicalInitialConcentrations:OnemayfindthattheproteinconcentrationneedstobeadjustedtoproducethebestdataChangingthishasaprofoundeffectonthedata,sosmallincrementsordecrementsarecalledforIfthatdoesnotproducereasonablygooddata,achangeinbuffercompositionmaybenecessaryItwouldalsobeagoodideatocheckthesampleforunforeseenaggregationviaDynamicLightScattering(DNArepairenzymesareanespeciallygoodexampleofthisbehavior)Ifbufferposesaproblem,cellswithshorterpath(mm)andacorrespondinglyincreasedproteinconcentrationandlongerscantimecanhelpWhenCDisappliedtoproteinswhatisthemainchromophore(absorbinggroup)thatislookedatWhatwavelengthrangedoesitabsorbinDoestheCDspectrumofaproteingivemostinformationaboutthe(i)primarystructure,(ii)secondarystructureor(iii)tertiarystructureDrawtheCDspectrumofanαhelixRemembertolabeltheaxesandmarkimportantpointswiththeirvaluesWhyisnitrogengasusedinCDinstrumentsDoesCDgiveinformationaboutwherethehelicesareinaproteinMembraneproteinsaredifficulttostudybyCDTrueorfalseWhy思考问题参考文献《生物物理学》赵南明周海梦高教出版社-施普林格出版社 ,p《园二色性和旋光色散在分子生物学中的应用》鲁子贤崔涛施庆洛科学出版社 CircularDichroismandLinearDichroism,AlisonRodgerandBengtNordén,OxfordUniversityPress《分析仪器手册》朱良漪孙亦梁陈耕燕化学工业出版社,pCircularDichroismandOpticalRotaryDispersionofProteinsandPolypeptides,AJAlder,NJGreenfieldandGDFasman,MethEnzymology,,()ComputedCircularDichroismSpectrafortheEvaluationofProteinConformation,NGreenfieldandGDFasman,Biochemistry,(),()CRCantorandPRSchimmel,BiophysicalChemistry,Vol,Chapter()EffectofTrifluoroethanolonProteinSecondaryStructure,FDSoennichsen,JEVanEyk,RSHodgesandBDSykes,Biochemistry,(),()ProteinSecondaryStructureandCircularDichroism:APracticalGuide,WCJohnson,PROTEINS,,()

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