摘要
Apoptosisisprimarilyexecutedbyactivecaspases,whicharederivedfromtheinactiveprocaspasezymogensthroughproteolyticcleavage.Wedeterminedthecrystalstructuresofacaspasezymogen,procaspase-7,andanactivecaspase-7withoutanyboundinhibitors.Comparedtotheinhibitor-boundcaspase-7,procaspase-7zymogenexhibitssignificantstructuraldifferencessurroundingthecatalyticcleft,whichprecludestheformationofaproductiveconformation.Proteolyticcleavageinbetweenthelargeandsmallsubunitsallowsrearrangementofessentialloopsintheactivesite,primingactivecaspase-7forinhibitor/substratebinding.Strikingly,bindingbyinhibitorscausesa180-degree-flippingoftheN-terminusinthesmallsubunit,whichinteractswithandstabilizesthecatalyticcleft.Theseanalysesrevealthestructuralmechanismsofcaspaseactivationanddemonstratethattheinhibitor/substratebindingisaprocessof
出版日期
2002年03月13日(中国期刊网平台首次上网日期,不代表论文的发表时间)