北大生物化學(xué)完整課件Chapter3 1

DateChapterLecturerMar.3Chapter1-2FoundationsofBiochemistry,waterDr.ChangMar.10

Chapter3.Aminoacids,peptidesandproteinsDr.SuMar.18*

Chapter3Aminoacids,peptidesandproteinsDr.SuMar.24*

Chapter4Thethree-dimensionalstructuresofproteinDr.Su

Mar.31Chapter4Thethree-dimensionalstructuresofproteinDr.SuApr.7

Chapter5ProteinFunctionDr.ChangApr.14Chapter5ProteinFunctionDr.ChangApr.21Chapter6EnzymesDr.ChangApr.28Chapter6EnzymesChapter8Nucleotidesandnucleicacids

Dr.ChangMay12Dr.KongMay19Chapter9DNA-basedinformationtechnoloogiesDr.KongMay26Chapter7CarbohydratesandGlycobiologyDr.QinJune2Chapter10LipidDr.QinJun.9Chapter11BiologicalmembranesandtansportDr.QinJun.16Chapter12Biosignaling

Dr.QinTeachingarrangementsforBiochemistryI2007(Drs.

ZengyiChang,

XiaodongSu,DaochunKong,

YongmeiQin)

Saturdays,8:00-11:00AM;電教112

Chapter3pp75-115AminoAcids,PeptidesandProteins

氨基酸、肽及蛋白質(zhì)Nelson,D.L.,andCox,M.M.(2005)LehningerPrinciplesofBiochemistry,4thedition.

Biochemistry

askshowtheremarkablepropertiesoflivingorganismsarisefromthethousandsofdifferentlifelessbiomolecules.Whenthesemoleculesareisolatedandexaminedindividually,theyconformtoallthephysicalandchemicallaws

thatdescribethebehaviorofinanimatematter—asdoalltheprocessesoccurringinlivingorganisms.

Thestudyofbiochemistryshowshowthecollectionsofinanimatemoleculesthatconstitutelivingorganismsinteracttomaintainandperpetuatelifeanimatedsolelybythephysicalandchemicallawsthatgovernthenonlivinguniverse.PrinciplesofBioenergetics/BiochemistryThetotalenergyoftheuniverseisconstant(能量守恒定律);Thetotalentropy(熵)iscontinuallyincreasing（熵增加原理）.—RudolfClausius,TheMechanicalTheoryofHeatwithItsApplicationstotheSteam-EngineandtothePhysicalPropertiesofBodies,1865(trans.1867)ATPFromPetrasP.DzejaandAndreTerzic

TheJournalofExperimentalBiology

206,

2039-2047(2003)DG=DH-TDSErwinSchr?dinger

(1887–1961)TheNobelPrizeinPhysics1933"forthediscoveryofnewProductiveformsofatomictheory"

Whatisprotein?Componentsoforganisms:Enzymes(metabolism)Transport(O2,membrane…)Movements(muscles)Antibodies(immunity)Brain……Protections(horns,skins…)J?nsJACOB

Berzelius(1779-1848)

He’saSwedishchemist,astudentofDalton.Hedevelopedtheconceptsoftheionandioniccompounds.Heintroducedtheclassicalsystemofchemicalsymbolsin1811,anddiscoveredanumberof

elements.

Berzeliuscoined(命名了)thewordsisomerism,allotropy,and

protein.

WheredoesthenamePROTEINcomefrom?YearInterweavingofthehistoricaltraditionsofbiochemistry,cellbiology,andgenetics.

Proteinswerethoughttocarrygeneticinformation182818971944MiescherdiscoveredDNATheNobelPrizeinPhysiologyorMedicine1953"forhisdiscoveryofthecitricacidcycle"HansAdolfKrebs(1900-1981)SheffieldUniversity,Sheffield,UnitedKingdomTheresearchIhavebeendoing-studyinghowfoodstuffsyieldenergyinlivingcells-doesnotleadtothekindofknowledgethatcanbeexpectedtogiveimmediatepracticalbenefitstomankind.Ihavechosenthisfieldofstudy,itwasbecauseIbelievedinitsimportanceinspiteofitstheoreticalcharacter.MyreasonforthisbeliefwasthatalllivingthingsmustbecontinuouslyfedwithenergyandIamconvincedthatanunderstandingoftheprocessofenergyproductionwilleventuallyhelpusinsolvingsomeofthepracticalproblemsofmedicine.

–NobelBanquetSpeech,Dec.1953TheNobelPrizeinPhysiologyorMedicine1962"fortheirdiscoveriesconcerningthemolecularstructureofnucleicacidsanditssignificancefor

information

transferinlivingmaterial"FrancisH.C.

Crick

MauriceH.F.Wilkins

JamesD.Watson

Thecentraldogma中心法則FlowofinformationingeneexpressionEverydayhomeworkforbiologists–Evolution！Currentphylogenytreeoflife(byCarlWoese)Metabolism新成代謝合成代謝分解代謝MetabolismPathwaysorNetworksAminoAcidsProteinscanbereducedtotheirconstituentaminoacidsbyavarietyofmethods.CommonStructuralFeaturesacarboxylgroup(羧基)anaminogroup（氨基）sidechains,orRgroupsWhentheRgroupcontainsadditionalcarbonsinachain,theyaredesignatedβ,γ,δ,ε,etc.,proceedingoutfromtheacarbon.Renantiomersorstereoisomers（立體異構(gòu)）

D,LsystemTheclassifiesofstandardaminoacidsbasedonRgroupFivemainclassesofaminoacids:nonpolarandaliphaticaromatic(generallynonpolar)polarbutunchargednegativelychargedpositivelycharged3.1.3Nonstandardaminoacids4－羥(基)脯氨酸5－羥(基)賴氨酸硒代半胱氨酸鏈霉素6－N－甲基賴氨酸γ

－羥基谷氨酸鳥氨酸瓜氨酸About300kindsofa.a.notoccurringinproteinsSelenocysteine-the21staminoacidSeCaCbHHHSecTheoccurrenceofSelenocysteine(Sec)wasfirstdemonstratedforproteinAofglycinereductase

Coneetal.1976Secisusedintheactivesiteofsomeredoxenzymes:formatedehydrogenase

glutathioneperoxidaseiodothyronine5'-deiodinaseTheonlygeneticallycodednon-standardaminoacid硒代半胱氨酸Prokaryotic

selenocysteine

incorporation4genesareessential:SelA

selenocysteine synthaseSelB

elongationfactor SelBSelC

tRNASecSelD

seleno- phosphate synthaseSelCO-C-C-CH2-OHINH2H

l

SeryltRNAsynthe