We have previously reported the detection of two unusual nucleotides,
pdJ and pdV, in the DNA of Trypanosoma brucei (Gommers-Ampt et al., 19
91). pdJ was found to be a novel nucleotide and is possibly involved i
n the regulation of variant specific surface antigen gene expression i
n trypanosomes. Recent evidence suggests that V could be a precursor o
f J, making V a key compound in the study of the biosynthesis and func
tion of J. We have therefore determined the structure of V and here we
present proof that V is HOMeU. The identity is based on a detailed co
mparison of dV(p) with authentic HOMedU(p), showing: I) co-migration i
n three different liquid chromatography analyses II) identical UV abso
rbance characteristics III) identical behavior in acetyl-pentafluorobe
nzyl derivatization and subsequent Gas chromatography/Mass spectrometr
y (GC/MS). The GC/MS technique has not been used before to analyse HOM
edU purified from biological material. Because of its high sensitivity
, it may also be useful for the detection of the low amounts of HOMedU
resulting from oxidative damage of DNA.