Pathways and mechanisms in the biogenesis of novel deoxysugars by bacteria

Science has long recognized the ubiquitously occurring deoxysugars as a novel and important class of carbohydrate, by virtue of the variety of potent and intriguing biological activities they exhibit. The study of the biosynthesis of these naturally vital molecules at a molecular level has received a great deal of attention in recent years, whether it be the well-established study of deoxyribonucleotide biosynthesis via ribonucleotide reductase or newer areas that include 3,6-dideoxyhexose construction and O antigen variation, as well as the emerging scrutiny of the biosynthesis of deoxysugar ligands of antibiotics and cardiac glycosides. This review attempts to update the various classes of deoxy, dideoxy, trideoxy, branched-chain, and amino sugars with respect to our current knowledge regarding the vast biological activities, genetics of formation, and molecular basis of their biosynthesis. In particular, the primary focus utilizes CDP-ascarylose biosynthesis, currently the best genetically and biochemically characterized dideoxysugar system, as a basis for comparison and postulation. This review helps display the elegant complexities of these essential natural saccharides and speculates upon tomorrow's potential applications.