Section D.ppt

hromosomeStructure(原核与真核生物的染色体结构)MolecularBiologyCourseD1 hromosome(原核染色体)D2 ChromatinStructure(染色质结构)D3 hromosome(真核染色体)D4 plexity(基因组复杂性)hromosomestructureD1 hromosome(原核染色体)hromosomestructureNucleoid(类核,拟核)–Bacterialchromosome细菌染色体鞭毛核糖体Asingleclosed-circularDNA,(类核)thatcontainshighconcentrationofDNA(upto30-50mg/ml),类核还包括与DNA结合的蛋白如聚合酶,阻抑物和其他成分Continuousreplication(nocellcycle)hromosomestructureD1--2DNAdomains(结构域)/loops(环)50--100个结构域或叫环Theendsofloopsareconstrainedtoprotein-membranecoreorscaffold每个环的末端被束缚到蛋白膜核心或叫做骨架的蛋白复合物上D1---hromosomestructureConsideraloopedDNA,ifthetwistingoftheDNAisinthesamedirectionasthatofthedoublehelix,thenthesupercoilingformedispositive;ifthehelixisuntwisted解除缠绕作用,,则形成正超螺旋;如果DNA双螺旋被解除缠绕,