Specificity of Cellular DNA-Binding Sites of Microbial Populations in a Florida Reservoir

摘要

Substrate specificity of the DNA binding mechanism(s) of bacteria in a Florida Reservoir was investigated in short and long term uptake studies with radiolabelled DNA and unlabelled competitors. Thymine oligonucleotides ranging in size from 2 bp to 19-24 bp inhibited DNA binding in 20 min incubations by 43 to 77%. Deoxynucleoside monophosphates, thymidine, and thymine had little effect on short term DNA binding, although several of these compounds inhibited the uptake of radiolabel from DNA in 4 h incubations. RNA inhibited both short and long term radiolabelled DNA uptake equally as well as unlabelled DNA. Collectively these results indicate that aquatic bacteria posses a generalized nucleic acid uptake/binding mechanism specific for compounds containing phosphodiester bonds and capable of recognizing oligonucleotides as short as dinucleotides.