第二章氨基酸和蛋白质.ppt

,AminoacidsandstructureacidsandbasesProteinstructuremyoglobinandhemoglobin,collagenProteinpurificationChromatographyofproteinsElectrophoresisofproteinsProteinsequencing,aminoacidsandprotein,Proteinsarethemostversatilemacromoleculesinlivingsystemsandservecrucialfunctionsinessentiallyallbiologicalprocesses.Theyfunctionascatalysts,theytransportandstoreothermoleculessuchasoxygen,theyprovidemechanicalsupportandimmuneprotection,theygeneratemovement,theytransmitnerveimpulses,andtheycontrolgrowthanddifferentiation,AminoAcid,Stereoisomers(stereo-isomer),The20standardaminoacids,Ionization,aminoacids,BasicStructureofanaminoacid,L-Aminoacid,D-Aminoacid,Thetwoenantiomersofaminoacid,Enantiomers,Enantiomersaremoleculesthathaveoppositespatialconfigurationaresaidtobeopticallyactive.Oneenantiomerwillrotatepolarizedlightasetnumberofdegreestotheright.Thisiscalledthedextrorotatoryisomeror(+)isomer.Theotherenantiomerwillrotatetheplanepolarizedlightthesamenumberofsetdegreesintheoppositeleftdirection.Thisisomerissaidtobealevorotatoryisomeror(-)isomer.,Thetwoenantiomersofanaminoacid,Hydrophobicaliphaticaminoacids,Hydrophobicaromaticaminoacids,Polarchargedaminoacids,Polarunchargedaminoacids,The20standardaminoacids,Hydrophobicaliphaticaminoacids,Gly:甘氨酸,glycine,Hydrophobicaliphaticaminoacids,Ala:丙氨酸,alanine,Hydrophobicaliphaticaminoacids,Val:缬氨酸,valine,Hydrophobicaliphaticaminoacids,Leu:亮氨酸,leucine,Hydrophobicaliphaticaminoacids,isolcuci,Ile:异亮氨酸,Hydrophobicaliphaticaminoacids,methionine,Met:甲硫氨酸,Hydrophobicaliphaticaminoacids,proline,Pro:脯氨酸,Hydrophobicaliphaticaminoacids,Cysteine,Cys:半胱氨酸,Hydrophobicaromaticaminoacids,Phe:苯丙氨酸,Phenylalanine,Hydrophobicaromaticaminoacids,Tyr:酪氨酸,Tyrosine,Hydrophobicaromaticaminoacids,Trp:色氨酸,Trptophan,Polarchargedaminoacids,Arg:精氨酸,Arginine,Polarchargedaminoacids,Lys:赖氨酸,Lysine,Polarchargedaminoacids,His:组氨酸,Histidine,Polarchargedaminoacids,Aspartate,Asp:天冬氨酸,Polarchargedaminoacids,Glu:谷氨酸,Glutamate,Polarunchargedaminoacids,Serine,Ser:丝氨酸,Polarunchargedaminoacids,Thr:苏氨酸,Threonine,Polarunchargedaminoacids,Asn:天冬酰胺,Asparagine,Polarunchargedaminoacids,Glutamine,Gln:谷氨酰胺,The20standardaminoacids,acids、basesandpHBufferIonizationofaminoacids,acidsandbases,acids、basesandpH,AnacidcanbedefinedasaprotondonorAbaseasaprotonacceptorAcidH+baseE.g:CH3COOHH+CH3COO-NH4+H+NH3ThepHofasolutionisameasureofitsconcentrationofprotons:pH=-lgH+,buffers,Anacid-baseconugatepaircanactasabuffer,resistingchangesinpH.,Ionization,Ionization,Nonionicform,Zwitterionicform,Dissociationofaminoacid,Titrationcurveofglycine,Peptidebond,Primarystructure,Secondarystructure,Tertiarystructure,Quaternarystructure,ProteinStructure,peptidebond,Peptideunitswithinapolypeptide,PeptideBondsArePlanar.Inapairoflinkedaminoacids,sixatoms(Ca,C,O,N,H,andCa)lieinaplane.Sidechainsareshownasgreenballs.,Primarystructure,AminoAcidsAreLinkedbyPeptideBondstoFormPolypeptideChains,Disulfidebond,Secondarystructure,SecondaryStructure:PolypeptideChainsCanFoldIntoRegularStructuresSuchastheAlphaHelix,theBetaSheet,andTurnsandLoops.Canapolypeptidechainfoldintoaregularlyrepeatingstructure?In1951,LinusPaulingandRobertCoreyproposedtwoperiodicstructurescalledtheahelix(alphahelix)andthebpleatedsheet(betapleatedsheet).Subsequently,otherstructuressuchasthebturnandomega(W)loopwereidentified.Althoughnotperiodic,thesecommonturnorloopstructuresarewelldefinedandcontributewithahelicesandbsheetstoformthefinalproteinstructure.,Thefoldingofthepeptidechainintoana-helix,-helix,-helix,H-bond,-sheet,Parallelandantiparallel-sheet,AParallelbSheet.,AnAntiparallelbSheet.,-sheet,Thefoldingofthepeptidechainina-turn,Super-secondarystructure,RossmanM.G.1973,STRUCTURALDOMAIN,Tertiarystructure,Water-SolubleProteinsFoldIntoCompactStructureswithNonpolarCoresTertiarystructure,referstothespatialarrangementofaminoacidsthatarefarapartinthelinearsequenceaswellasthoseresiduesthatareadjacent.,H-bondintertiarystructure,Quaternarystructure,Quaternarystructurereferstothespatialarrangementofthepolypeptidesubunitsandthenatureoftheinteractionsbetweenthem.Theseinteractionsmaybecovalentlinksornon-covalentinteractions,Quaternarystructure,Simplequaternarystructure,Levelsofstructureinproteins,Proteinstability,Non-covalentinteractions(electrostaticforces,hydrogenbonds,hydrophobicforces)covalentinteractions(disulfidebonds)Peptidebonds,Proteinfolding,SpontaneouslyfoldHydrophobicforceOrderedsetofpathwaysAccessoryprotein:ProteindisulfideisomerasePeptidylprolylcis-tranisomeraseMolecularchaperone,myoglobinandhemoglobin,Oxygen-bindingproteinsMyoglobin肌红蛋白Hemoglobin血红蛋白BindingofoxygentohemeAllostery别构MechanismoftheallostericchangeThebohreffectFetalhemoglobin胎儿血红蛋白Hemoglobinopathies血红蛋白病,Oxygen-bindingproteins,MyoglobinandHemoglobinarethetwooxygen-bindingproteinspresentinlargemulticellularorganisms.Hemoglobintransportsoxygeninthebloodandislocatedintheerythrocytes;Myoglobinstorestheoxygeninthemuscles.,Myoglobin,Myoglobinstructure,Hemoglobin,PROTOPORPHYRINIX原卟啉,Heme血红素,Ferriheme高铁血红素,animation,hemo,Allostery变构,AllostericproteinCooperativeNon-cooperativeOxygendissociatiocurves(Sigmoidal,hyperbolic),OxygendissocationcurvesforHbandMb,Thebohreffect,Thebohreffect,Fetalhemoglobin,Fetalhemo,B5collagen,FunctionanddiversityBiosynthesisCompositionandpost-translationalmodificationsStructureSecretionandaggregationCross-linksBoneformation,collagen,collagen,collagen,COLLGENSYNTHIESIS,COLLEGENBOND,collgen,ProteinSolubility,Proteinsize,Proteincharge,Proteinspecificbindingaffinity,B6ProteinPurification,Selectionofaproteinsource,Homogenizationandsolubilization,Stabilizationofproteins,Assayofproteins,Principlesofproteinpurification,Gelfiltrationchromatography,Ionexchangechromatography,Affinitychromatography,B7Chromatographyofproteins,Gelfiltrationchromatography,fig,Gelfiltrationchromatography,Gelfiltrationchromatography,Ionexchangechromatography,Affinitychromatography,NativePAGE,SDS-PAGE,Isoelectricfocusing,B8ElectrophoresisofProtein,Visualizationofproteinsingels,electrophoresis,Nativepolyacrylamidegelelectropphoresis,Determinationofthemolecularmassofunknownproteinbyelectrophoresis,Isoelectricfocusing,Isoelectricfocusing,Isoelectricfocusing,Two-dimensionalgelelectrophoresis,Appearanceofproteinafterelectrophoresis,Aminoacidcompositionanalysis,Edmandegradation,Sequencingstrategy,B9Proteinsequencingandpeptidesynthesis,Aminoacidcompositionanalysis,Hydroli