BASE SEQUENCE DETERMINATION IN NUCLEIC ACIDS WITH THE ELECTRON MICROSCOPE, III. CHEMISTRY AND MICROSCOPY OF GUANINE-LABELED DNA

Abstract

Diazotized 2-amino-p-benzenedisulphonic acid can selectively label the guanine residues in DNA. The reaction is mild and no excessive degradation of the polymer chain is observed, DNA so labeled and stained with uranyl acetate is visible in the electron microscope and the markers resolved in pairs of dots 10-12 A apart. Pairs have been observed spaced 6-7 A from each other, suggesting labeling of consecutive guanine residues.