Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

Abstract

Two analogues of 3-(dimethylsulfonio)propanoate (DMSP), 3-(diallylsulfonio)propanoate (DAllSP), and 3-(allylmethylsulfonio)propanoate (AllMSP), were synthesized and fed to marine bacteria from the Roseobacter clade. These bacteria are able to degrade DMSP into dimethyl sulfide and methanethiol. The DMSP analogues were also degraded, resulting in the release of allylated sulfur volatiles known from garlic. For unknown compounds, structural suggestions were made based on their mass spectrometric fragmentation pattern and confirmed by the synthesis of reference compounds. The results of the feeding experiments allowed to conclude on the substrate tolerance of DMSP degrading enzymes in marine bacteria.

On the Substrate Scope of Dimethylsulfonium Propionate Lyases toward Dimethylsulfoxonium Propionate Derivatives

“…Furthermore, in our previous research we have demonstrated that DMSP lyases can also cleave various DMSP analogs e. g. with longer alkyl chains or with the sulfur atom exchanged with other heteroatoms, demonstrating that DMSP lyases exhibit a broad substrate tolerance. [42][43][44][45] The present study has demonstrated that also DMSOP analogs with longer alkyl chains can be converted by DMSP lyases, with a poor enantioselectivity for the chiral substrates, which further expands the generally broad substrate spectrum of this remarkably diverse family of enzymes.…”

“…Interestingly, feeding experiments with DMSP analogs containing an S-allyl group including diallylsulfonium propionate (14, DAllSP) and allylmethylsulfonium propionate (15, AllMSP) result in the formation of garlic odour constituents, with the consequence that cultures of bacteria that are able to degrade DMSP fed with these substances release the smell of garlic. [44] Also DMSP analogs containing sulfur heterocycles as in tetramethylenesulfonium propionate (16, TMSP), [43] or with the sulfur atom substituted by other atoms or groups as represented by dimethylselenium propionate (17, DMSeP), [42] dimethyltellurium propionate (18, DMTeP), [42] and trimethylammonium propionate (19, TMAP) [45] are accepted by various DMSP lyases. In contrast, nothing is known about the substrate tolerance and efficiency of the cleavage of DMSOP analogs mediated by DMSP lyases.…”

“…DMSP lyases do not only accept their native substrates DMSP and DMSOP, but are also able to catalyze the cleavage of various DMSP analogs with larger S‐alkyl substituents including ethylmethylsulfonium propionate ( 10 , EMSP), [42] diethylsulfonium propionate ( 11 , DESP), [42] methylpropylsulfonium propionate ( 12 , MPSP), [43] and isopropylmethylsulfonium propionate ( 13 , IMSP) [43] (Scheme 1D). Interestingly, feeding experiments with DMSP analogs containing an S‐allyl group including diallylsulfonium propionate ( 14 , DAllSP) and allylmethylsulfonium propionate ( 15 , AllMSP) result in the formation of garlic odour constituents, with the consequence that cultures of bacteria that are able to degrade DMSP fed with these substances release the smell of garlic [44] . Also DMSP analogs containing sulfur heterocycles as in tetramethylenesulfonium propionate ( 16 , TMSP), [43] or with the sulfur atom substituted by other atoms or groups as represented by dimethylselenium propionate ( 17 , DMSeP), [42] dimethyltellurium propionate ( 18 , DMTeP), [42] and trimethylammonium propionate ( 19 , TMAP) [45] are accepted by various DMSP lyases.…”