Bacterial triterpenoids of the hopane series from the prochlorophyte Prochlorothrix hollandica and their intracellular localization.

35-O-beta-Galacturonopyranosyl-, 35-O-beta-3,5-anhydro-galacturonopyranosyl- and 35-O-alpha-altruronopyranosylbacteriohopanetetrol accompanied by their 2 beta-methyl homologues have been isolated from Prochlorothrix hollandica. We report here C35 triterpenoids of the hopane series in a prochlorophyte, a group of prokaryotic oxigenic phototrophs of the cyanobacterial lineage. Like many cyanobacteria, P. hollandica contains a mixture of non-methylated as well as 2 beta-methylhopanoids. After side-chain cleavage by periodic acid oxidation followed by sodium borohydride reduction, these hopanoids could be localized in cell walls and thylakoids, in accordance with their role as membrane stabilizers.