Major advances over the past decade in the field of ancient DNA are providing access to past paleogenomic diversity, but the diverse functions and biosynthetic capabilities of this growing paleome remain largely elusive. Here, we investigated the dental calculus of 12 Neanderthals and 52 anatomically modern humans spanning 100 kya to the present and reconstructed 459 bacterial metagenome-assembled genomes (MAGs). We identified a biosynthetic gene cluster (BGC) shared by seven Middle and Upper Paleolithic individuals that allows for the heterologous production of a class of previously unknown metabolites we name paleofurans. This paleobiotechnological approach demonstrates that viable biosynthetic machinery can be produced from the preserved genetic material of ancient organisms, allowing access to natural products from the Pleistocene and providing a promising area for natural product exploration.
A variety of 2,3-diiodinated biphenyl and iodinated meta-terphenyl derivatives were synthesized by a regioselective Suzuki-Miyaura cross-coupling reaction of 5-substituted 1,2,3triiodobenzenes. By using 1 equiv. of arylboronic acid, the Suzuki-Miyaura reaction yielded 2,3-diiodinated biphenyl derivatives with excellent regioselectivity. The coupling reaction predominantly occurred at the terminal position of the P. O.
Mycobacteria produce several unusual cofactors that contribute to their metabolic versatility and capability to survive in different environments. Mycofactocin (MFT) is a redox cofactor involved in ethanol metabolism. The redox-active core moiety of mycofactocin is derived from the short precursor peptide MftA, which is modified by several maturases. Recently, it has been shown that the core moiety is decorated by a β-1,4-glucan chain. Remarkably, the second glucose moiety of the oligosaccharide chain was found to be 2-O-methylated in Mycolicibacterium smegmatis. The biosynthetic gene responsible for this methylation, however, remained elusive, and no methyltransferase gene was part of the MFT biosynthetic gene cluster. Here, we applied reverse genetics to identify the gene product of MSMEG_6237 (mftM) as the SAM-dependent methyltransferase was responsible for methylation of the cofactor in M. smegmatis. According to metabolic analysis and comparative genomics, the occurrence of methylated MFT species was correlated with the presence of mftM homologues in the genomes of mycofactocin producers. This study revealed that the pathogen Mycobacterium tuberculosis does not methylate mycofactocins. Interestingly, mf tM homologues cooccur with both mycofactocin biosynthesis genes as well as the putative mycofactocin-dependent alcohol dehydrogenase Mdo. We further showed that mftM knock-out mutants of M. smegmatis suffer from a prolonged lag phase when grown on ethanol as a carbon source. In addition, in vitro digestion of the glucose chain by cellulase suggested a protective function of glucan methylation. These results close an important knowledge gap and provide a basis for future studies into the physiological functions of this unusual cofactor modification.
Cu(I) catalysts enable C–B
bond formation via direct insertion
of vinyldiazoacetates into B–H bonds of borane–phosphine
Lewis adducts to form phosphine-protected allylboranes under mild
conditions. The resulting allylborane–phosphine Lewis adducts
can be used in the diastereoselective allylation of aldehydes directly
without the need for removal of the phosphine. The allylation reaction
proceeds with high diastereoselectivity and yields 5,6-disubstituted
dihydropyranones after treatment with an appropriate acid.
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