Chemical structure of 1-O-(L-erythro-biopterin-2′-y1)-α-glucose isolated from a cyanobacterium Synechococcus sp. PCC 7942

Abstract

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-O-(L-erythro-biopterin-2′-y1)-α-glucose. It is the first report on the occurrence of a biopterin-glucoside having a α-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 α-glucosyltransferase.