A pteridine glycoside in Synechococcus sp. PCC 7942, the structure of which had been tentatively identified
as biopterin-glucoside, was isolated and characterized for its exact chemical structure by 2D-NMR spectroscopy.
The determined structure is 1-0-(L-erythro-biopterin-2'-yl)-a-glucose. It is the first report on the occurrence of a
biopterin-glucoside having a a-configured sugar directly attached at the pteridine ring. This result also supports
that the previously purified UDP-glucose: BH4 glucosyltransferase from Synechococcus sp. PCC 7942, which
catalyzes the synthesis of BH4-glucoside from UDP-glucose and BH4, is a a-glucosyltransferase.