摘要
Thecrygenefamily,producedduringthelateexponentialphaseofgrowthinBacil-lusthuringiensis,isalarge,still-growingfamilyofhomologousgenes,inwhicheachgeneencodesaproteinwithstrongspecificactivityagainstonlyoneorafewin-sectspecies.ExtensivestudiesaremostlyfocusingonthestructuralandfunctionalrelationshipsofCryproteins,andhaverevealedseveralresiduesordomainsthatareimportantforthetargetrecognitionandreceptorattachment.Inthisstudy,wehaveemployedamaximumlikelihoodmethodtodetectevidenceofadaptiveevolutioninCryproteins,andhaveidentified24positivelyselectedresidues,whicharealllocatedinDomainIIorIII.Combinedwithknowndatafrommutagenesisstudies,themajorityoftheseresidues,atthemolecularlevel,contributemuchtotheinsectspecificitydetermination.WepostulatethatthepotentialpressuresdrivingthediversificationofCryproteinsmaybeinanattempttoadaptforthe'armrace'betweenδ-endotoxinsandthetargetedinsects,ortoenlargetheirtar-getspectra,henceresultinthefunctionaldivergence.ThesitesidentifiedtobeunderpositiveselectionwouldprovidetargetsforfurtherstructuralandfunctionalanalysesonCryproteins.
出版日期
2007年02月12日（中国期刊网平台首次上网日期，不代表论文的发表时间）
