Antibiotic optimization via in vitro glycorandomization

Abstract

In nature, the attachment of sugars to small molecules is often used to mediate targeting, mechanism of action and/or pharmacology. As an alternative to pathway engineering or total synthesis, we report a useful method, in vitro glycorandomization (IVG), to diversify the glycosylation patterns of complex natural products. We have used flexible glycosyltransferases on nucleotide diphosphosugar (NDP-sugar) libraries to generate glycorandomized natural products and then applied chemoselective ligation to produce monoglycosylated vancomycins that rival vancomycin.

Enhancing the anticancer properties of cardiac glycosides by neoglycorandomization

“…In this prototype example, we show that subtle sugar modifications can dramatically, and independently, modulate both the cytotoxic properties and the Na ϩ ͞K ϩ -ATPaseinhibitory properties of cardiac glycosides. The potential of neoglycorandomization is further augmented by its compatibility with chemical handles (e.g., azido groups) for additional elaboration (8,9). Neoglycorandomization is limited solely by the efficiency and specificity of alkoxylamine handle installation and the availability of reducing sugar donors; thus, these studies highlight the unique potential of neoglycosylation and͞or neoglycorandomization as a universally powerful tool for glycobiology and drug discovery.…”

“…In an effort to explore the contribution of the sugar constituents of pharmaceutically relevant glycosylated natural products, we have developed chemoenzymatic ''glycorandomization'' methods (Fig. 1A, path B) to rapidly convert a single aglycon structure into a library of analogs with a broad array of sugar attachments (9,10). Despite these advances, chemoenzymatic glycorandomization currently excludes a number of essential glycoconjugates because it is limited to natural products for which promiscuous glycosyltransferases are available and can operate in vitro.…”

Enzymatic synthesis of vancomycin derivatives using galactosyltransferase and sialyltransferase

“…Furthermore, galactosylation of vancomycin antibiotics (8) Enzymatic glycosylations using b1,4GalT and a2,3SiaT T-J Oh et al a significant factor in the improvement of activity against vancomycin-resistant enterococci. 13,14 Therefore, the ability to generate additional sugar variants of vancomycin by using dedicated glycosyltransferases would be of particular interest. Diversification of vancomycin through chemoenzymatic strategies to identify new derivatives with novel biological activities has been a practical process; however, these strategies have several limitations, including difficulty synthesizing the sugar donor and substrate specificity.…”

Creation of the first anomeric d / l -sugar kinase by means of directed evolution

“…8 and references therein). Among these, in vitro glycorandomization (IVG) makes use of the inherent or engineered substrate promiscuity of nucleotidylyltransferases and glycosyltransferases to activate and attach chemically synthesized sugar precursors to various natural product scaffolds (6,7,(9)(10)(11)(12)(13)(14)(15), the advantage of which is the ability to efficiently incorporate highly functionalized ''unnatural'' sugar substitutions into the corresponding natural product scaffold (Fig. 1b).…”

“…1b). In a recent demonstration of IVG, Ͼ50 analogs of 5 were generated, some of which displayed enhanced and distinct antibacterial profiles from the parent natural product (13).…”