{"title":"Comparative investigation of rate of sedimentation of DNA from human fibroblasts and tumor cells of HeLa line before and after moderate heating.","authors":"M M Vilenchik, A N Khokhlov","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>Changes in DNA after heating of human cells at 43.5 and 44 degrees C were found for the first time by means of sedimentation in an alkaline sucrose gradient. These changes are probably mainly determined by three processes: the appearance in DNA of alkali-labile bonds, the formation of stable DNA--protein complexes, and changes in the superstructure of the DNA, in particular partial unfolding of the nucleosomes. The existence of a mechanism for nonexcision repair of thermal lesions in DNA by an enzyme (\"repurinase\") catalyzing the formation of a glycoside bond between the base of a purine precursor of DNA and the deoxyribose residue of an apurine component is suggested.</p>","PeriodicalId":9166,"journal":{"name":"Biology bulletin of the Academy of Sciences of the USSR","volume":"7 1","pages":"33-9"},"PeriodicalIF":0.0000,"publicationDate":"1980-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biology bulletin of the Academy of Sciences of the USSR","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Changes in DNA after heating of human cells at 43.5 and 44 degrees C were found for the first time by means of sedimentation in an alkaline sucrose gradient. These changes are probably mainly determined by three processes: the appearance in DNA of alkali-labile bonds, the formation of stable DNA--protein complexes, and changes in the superstructure of the DNA, in particular partial unfolding of the nucleosomes. The existence of a mechanism for nonexcision repair of thermal lesions in DNA by an enzyme ("repurinase") catalyzing the formation of a glycoside bond between the base of a purine precursor of DNA and the deoxyribose residue of an apurine component is suggested.