单分子荧光共振能量传递及系综生物物理表征人体肌细胞增强因子2d启动子形成的g-四链体

dnag-quadruplexes(g4s)arebelievedtobeinvolvedinmanybiologicalprocesses,includingthegeneexpressionregulationandthemaintenanceoftelomere.however,thekineticsofg4,inparticularhowg4formsinthedouble-strandedgenomicdnaisanunderexploredissue.wefoundthataverystableg4canforminthepromoterofhumanmyocyteenhancerfactor2d(mef2d),thegeneencodesatranscriptionfactorbelongingtothemef2(myocyteenhancerfactor-2)familywhichregulatestheresponseofhearttocardiacstresssignals.biophysicalcharacterizations,inparticularsinglemoleculefluorescenceresonanceenergytransfer(smfret)measurements,suggestthatthisg4ismorestablethanitsduplexforminnearphysiologicalconditions.twomajorg4structureswereidentifiedbasedonsinglemoleculeconformationalanalysisontheendandinternallabeleddnasystems.afreeenergylandscapefortheg4hybridizationwasestablishedinlightofthesmfretg4/duplexcompetitionassay.inaddition,theg4hybridizationandunfoldingrateconstantswereobtained.