(-)-Verrucosan-2 -ol from the phototrophic bacterium Chloroflexus aurantiacus: first report of a verrucosane-type diterpenoid from a prokaryote

Abstract

~_ _ _ _ _ _ _ _ _ _ _ _____(-)-Verrucosan-2fil ( C s N 0 ) , a rare diterpene with a 3,6,6,5-tetracyclic ring system, has been isolated and identilied for the first time from the phototrophic bacterium Chluruflexus aurantiacus. Furthermore, an unsaturated diterpenoid hydrocarbon (Cd,,) with a similar carbon skeleton was found in the same organism. This prokaryote, naturally occurring in hot spring microbial mats, is considered to be one of the oldest bacterial life forms on earth. Verrucosane-type diterpenoids had previously been detected only in some liverworts (Hepaticae), forming a unique group in the plant kingdom.

Biosynthesis of the Diterpene Verrucosan-2β-ol in the Phototrophic Eubacterium Chloroflexus aurantiacus

“…Additional information was gleaned from two-dimensional INADEQUATE experiments using 13 C-labeled samples isolated from the growth experiments with 13 C-labeled acetate (see below). With the exception of C-3 and C-16 which had to be interchanged, the data were in line with those obtained in CD 2 Cl 2 by Hefter et al (11).…”

“…A 1 H and 13 C NMR analysis of verrucosan-2␤-ol with CD 2 Cl 2 as solvent has been reported by Hefter et al (11). Our initial NMR analysis using CDCl 3 as solvent gave some ambiguities with respect to the published assignments.…”

“…13 C]Acetate and [2-13 C]acetate were purchased from MSD-Isotopes (IC-Chemikalien, Mü nchen, Germany) and [1,[2][3][4][5][6][7][8][9][10][11][12][13] C 2 ]acetate from Isotec (Miamisburg, OH). Gases were purchased from Linde AG (Höllriegelskreuth, Germany).…”

“…Hopanoids and steroids have not been found in the membrane of C. aurantiacus. Despite its different molecular dimensions, it has been proposed that verrucosan-2␤-ol can act as a modulator of membrane fluidity in analogy to hopanoids and steroids in other microorganisms (11).…”

The isolation of isoagathenediol: a new tricyclic diterpene from the lipids of Rhodospirillum rubrum

“…It has, however, been chemically synthesized (Nishizawa e t al., 1986 ;Vlad e t al., 1986) and named according to Vlad et al ( 1 986) based on the nomenclature of isoagatholactone. Previous to this study, the only known microbial diterpenes were the carotenoid intermediate, geranylgeraniol pyrophosphate (Langworthy, 1982), a chemically uncharacterized gibberellin from Arotobacter uinelandii (Lee et al, 1970) and verrucosan-2P-01 from Chloroflexus aurantiacus (Hefter et al, 1993).…”