A5088531918- Glycosylation and Glycoproteins Research
- Carbohydrate Chemistry and Synthesis
- Enzyme Production and Characterization
- Genomics and Phylogenetic Studies
- Microbial Natural Products and Biosynthesis
- Infant Nutrition and Health
- Plant biochemistry and biosynthesis
- Digestive system and related health
- Bacterial Infections and Vaccines
- Enzyme Structure and Function
- Enzyme Catalysis and Immobilization
- Influenza Virus Research Studies
- Fungal Biology and Applications
- Proteoglycans and glycosaminoglycans research
- Phase-change materials and chalcogenides
- Microbial infections and disease research
- Advanced Fluorescence Microscopy Techniques
- Galectins and Cancer Biology
- Chemical synthesis and alkaloids
- Biochemical and Molecular Research
- Breastfeeding Practices and Influences
University of California, Davis
2015-2021
University of California System
2017-2019
SHIELDS for Families
2018
North Carolina State University
2013-2017
β1–3-Linked galactosides such as Galβ1–3GlcNAcβOR are common carbohydrate motifs found in human milk oligosaccharides (HMOSs), glycolipids, and glycoproteins. Efficient scalable enzymatic syntheses of these structures have proven challenging because the lack access to a highly active β1–3-galactosyltransferase (β3GalT) large amounts. Previously reported E. coli β3GalT (EcWbgO) has been identified limiting factor for producing β1–3-galactose-terminated oligosaccharide lacto-N-tetraose (LNT)...
Acyltransferase (AT) domains of polyketide synthases (PKSs) select extender units for incorporation into polyketides and dictate large portions the structures clinically relevant natural products. Accordingly, there is significant interest in engineering substrate specificity PKS ATs order to site-selectively manipulate structure. However, previous attempts engineer have yielded mutant PKSs with relaxed unit specificity, rather than an inversion selectivity from one another. Here, by...
Polyketide synthases construct polyketides with diverse structures and biological activities via the condensation of extender units acyl thioesters. Although a growing body evidence suggests that polyketide might be tolerant to non-natural units, in vitro vivo studies aimed at probing utilizing synthase specificity are severely limited only small number owing lack synthetic routes broad variety acyl-CoA units. Here, we report construction promiscuous malonyl-CoA synthetase variants can used...
During polyketide biosynthesis, acyltransferases (ATs) are the essential gatekeepers which provide assembly lines with precursors and thus contribute greatly to structural diversity. Previously, we demonstrated that discrete AT KirCII from kirromycin antibiotic pathway accesses nonmalonate extender units. Here, exploit promiscuity of generate new kirromycins allyl- propargyl-side chains in vivo, latter were utilized as educts for further modification by "click" chemistry.
Combinatorial biosynthesis approaches that involve modular type I polyketide synthases (PKSs) are proven strategies for the synthesis of polyketides. In general however, such usually limited in scope and utility due to restricted substrate specificity biosynthetic machinery. Herein, a panel chemo-enzymatically synthesized acyl-CoA's was used probe promiscuity synthase. Promiscuity determinants were dissected, revealing KS is remarkably tolerant diverse array extender units, while AT likely...
A highly efficient streamlined chemoenzymatic strategy for total synthesis of four prioritized ganglioside cancer antigens GD2, GD3, fucosyl GM1, and GM3 from commercially available lactose phytosphingosine is demonstrated. Lactosyl sphingosine (LacβSph) was chemically synthesized (on a 13 g scale), subjected to sequential one-pot multienzyme (OPME) glycosylation reactions with facile C18-cartridge purification, followed by improved acylation conditions form target gangliosides, including...
A chemoenzymatic synthon was designed to expand the scope of synthesis carbohydrates. The enzymatically converted into carbohydrate analogues, which were readily derivatized chemically produce desired targets. strategy is demonstrated for glycosides containing 7,9-di-N-acetyllegionaminic acid (Leg5,7Ac2 ), a bacterial nonulosonic (NulO) analogue sialic acid. versatile library α2-3/6-linked Leg5,7Ac2 -glycosides built by using synthesized 2,4-diazido-2,4,6-trideoxymannose as highly efficient...
A sialyltransferase mutant for selectively α2–6-sialylating terminal galactose in polyLacNAc-glycan was identified using a novel microtiter plate-based screening assay.
heparosan synthase 2 (PmHS2) is a dual-function polysaccharide having both α1-4-N-acetylglucosaminyltransferase (α1-4-GlcNAcT) and β1-4-glucuronyltransferase (β1-4-GlcAT) activities located in two separate catalytic domains. We found that removing PmHS2 N-terminal 80-amino acid residues improved enzyme stability expression level while retaining its substrate promiscuity. also identified the reverse glycosylation of which complicated application size-controlled synthesis oligosaccharides...
The lack of α2–6-linkage specific sialidases limits the structural and functional studies sialic-acid-containing molecules. Photobacterium damselae α2–6-sialyltransferase (Pd2,6ST) was shown previously to have α2–6-specific, but weak, sialidase activity. Here, we develop a high-throughput blue-white colony screening method identify Pd2,6ST mutants with improved α2–6-sialidase activity from mutant libraries generated by sequential saturation mutagenesis. A triple (Pd2,6ST S232L/T356S/W361F)...
5,7-Di-N-acetyllegionaminic acid (Leg5,7Ac2) is a bacterial nonulosonic (NulO) analogue of sialic acids, an important class monosaccharides in mammals and some bacteria. To develop efficient one-pot multienzyme (OPME) glycosylation systems for synthesizing Leg5,7Ac2-glycosides, Legionella pneumophila cytidine 5'-monophosphate (CMP)-Leg5,7Ac2 synthetase (LpCLS) was cloned characterized. It successfully used producing Leg5,7Ac2-glycosides from chemoenzymatically synthesized Leg5,7Ac2 using...
Cytidine 5′-monophosphate (CMP)-sialic acid synthetase (CSS) is an essential enzyme involved in the biosynthesis of carbohydrates and glycoconjugates containing sialic acids, a class α-keto acids that are generally terminal key recognition residues by many proteins play important biological pathological roles. The CSS from Neisseria meningitidis (NmCSS) has been commonly used with other enzymes such as aldolase and/or sialyltransferase synthesizing diverse array compounds or its naturally...
Abstract A chemoenzymatic synthon was designed to expand the scope of synthesis carbohydrates. The enzymatically converted into carbohydrate analogues, which were readily derivatized chemically produce desired targets. strategy is demonstrated for glycosides containing 7,9‐di‐ N ‐acetyllegionaminic acid (Leg5,7Ac 2 ), a bacterial nonulosonic (NulO) analogue sialic acid. versatile library α2‐3/6‐linked Leg5,7Ac ‐glycosides built by using synthesized 2,4‐diazido‐2,4,6‐trideoxymannose as highly...
Carbohydrate-Active enZYme (CAZY) GH89 family enzymes catalyze the cleavage of terminal α-N-acetylglucosamine from glycans and glycoconjugates. Although structurally mechanistically similar to human lysosomal α-N-acetylglucosaminidase (hNAGLU) in which is involved degradation heparan sulfate lysosome, reported bacterial characterized so far have no or low activity toward α-N-acetylglucosamine-terminated heparosan oligosaccharides, preferred substrates hNAGLU. We cloned expressed several...