生物技術及應用專業教學資源庫EnglishForBiotechnology專業英語Chapter6ProteinengineeringUnit1

Introductionof

ProteinengineeringIntroductionofProteinengineering

Proteinengineeringistheprocessofdevelopingusefulorvaluableproteins.Itisayoungdiscipline,withmuchresearchcurrentlytakingplaceintotheunderstandingofproteinfoldingandproteinrecognitionforproteindesignprinciples.蛋白質工程是開發有用或有價值蛋白質的過程。蛋白質工程是開發有用或有價值蛋白質的過程。這是一個新興的學科，目前在蛋白質的折疊和蛋白質的識別方向開展了大量的研究，以便進行蛋白質的設計。WhatisProteinEngineering？

IntroductionofProteinengineeringTherearetwogeneralstrategiesforproteinengineering.Thefirstisknownasrationaldesign,Thesecondstrategyisknownasdirectedevolution.蛋白質工程有兩種策略。第一種是理性的設計，第二種策略是定向進化。TwogeneralstrategiesforproteinengineeringIntroductionofProteinengineeringRationaldesignistomakedesiredchangesbyusingdetailedknowledgeofthestructureandfunctionoftheprotein.理性的設計，是運用蛋白質結構和功能的詳細知識進行所需的改造。RationalDesignIntroductionofProteinengineeringRationaldesignhastheadvantageofbeinggenerallyinexpensiveandeasy,sincesite-directedmutagenesistechniquesarewell-developed.However,thereisamajordrawbackinthatdetailedstructuralknowledgeofaproteinisoftenunavailable,andevenwhenitisavailable,itcanbeextremelydifficulttopredicttheeffectsofvariousmutations.由于定點突變技術已得到很好的發展，這種設計方式具有價格便宜、操作簡便的優勢，然而，該方式有一個主要的缺點，那就是蛋白質的詳細結構信息往往不清楚，即使搞清楚了，各種突變的影響也很難預料。RationalDesign:site-directedmutagenesisIntroductionofProteinengineeringComputationalproteindesignalgorithmsseektoidentifyaminoacidsequencesthathavelowenergiesfortargetstructures.計算機蛋白質設計的算法正在尋求如何確定氨基酸序列，以使目標蛋白結構具有較低的能量。RationalDesign:computationalproteindesignIntroductionofProteinengineeringWhilethesequence-conformationspacethatneedstobesearchedislarge,themostchallengingrequirementforcomputationalproteindesignisafast,yetaccurate,energyfunctionthatcandistinguishoptimalsequencesfromsimilarsuboptimalones.Usingcomputationalmethods,aproteinwithanovelfoldhasbeendesigned,aswellassensorsforun-naturalmolecules.然而，對于序列和空間構象之間的關系需要進行大量的研究，計算機蛋白質設計更大的挑戰在于如何準確、迅速地通過能量函數區分最佳序列。運用計算機輔助的方法．可以設計一種具有新的折疊方式的蛋白質，以及非天然分子的傳感器。RationalDesignIntroductionofProteinengineeringDirectedevolutioniswhererandommutagenesisisappliedtoaprotein,andaselectionregimeisusedtopickoutvariantsthathavethedesiredqualities.Furtherroundsofmutationandselectionarethenapplied.Thismethodmimicsnaturalevolutionandgenerallyproducessuperiorresultstorationaldesign.定向進化是對蛋白質進行隨機突變，然后篩選出具有所需性能的蛋白質。不斷地循環運用突變和篩選。該方法模擬自然進化過程，可以取得比理性設計更好的效果。DirectedEvolutionIntroductionofProteinengineeringAnadditionaltechniqueknownasDNAshufflingmixesandmatchespiecesofsuccessfulvariantsinordertoproducebetterresults.Thisprocessmimicsrecombinationthatoccursnaturallyduringsexualreproduction.DNA重組技術將成功改造的各種突變體進行混合和匹配，以便產生更好的效果。這個過程模仿天然有性繁殖中發生的重組過桯。DirectedEvolution:DNAshufflingIntroductionofProteinengineeringThegreatadvantageofdirectedevolutiontechniquesisthattheyrequirenopriorstructuralknowledgeofaprotein,norisitnecessarytobeabletopredictwhateffectagivenmutationwillhave.Indeed,theresultsofdirectedevolutionexperimentsareoftensurprisinginthatdesiredchangesareoftencausedbymutationsthatnoonewouldhaveexpected.定向進化技術的巨大優勢是，人們不需要事先知道蛋白質的結構知識，也不必預測給定的突變會產生什么影響。事實上，定向進化實驗的結果往往出人意料，突變經常產生意想不到的所期望的變化。DirectedEvolution–AdvantageIntroductionofProteinengineeringThedrawbackisthattheyrequirehigh-throughput,whichisnotfeasibleforallproteins.LargeamountsofrecombinantDNAmustbemutatedandtheproductsscreenedfordesiredqualities.Thesheernumberofvariantsoftenrequiresexpensiveroboticequipmenttoautomatetheprocess.Furthermore,notalldesiredactivitiescanbeeasilyscreenedfor.該方法的缺點是需要較高的通量，這并不是對所有蛋白質都可行。對大量的重組DNA進行突變，然后根據所需的性狀進行篩選。為了篩選大量的突變體，往往需要昂貴的機器設備，以實現篩選過程的自動化。而且，并非所有需要的活性都可以很容易地篩選獲得。DirectedEvolution–DrawbackIntroductionofProteinengineeringRationaldesignanddirectedevolutiontechniquesarenotmutuallyexclusive;goodresearcherswilloftenapplyboth.Inthefuture,moredetailedknowledgeofproteinstructureandfunction,aswellasadvancementsinhigh-throughputtechnology,willgreatlyexpandthecapabilitiesofproteinengineering.Eventuallyevenunnaturalaminoacidsmaybeincorporatedthankstoanewmethodthatallow