Xianxuan Zhou

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In quorum sensing (QS) process, bacteria regulate gene expression by utilizing small signaling molecules called autoinducers in response to a variety of environmental cues. Autoinducer 2 (AI-2), a QS signaling molecule proposed to be involved in interspecies communication, is produced by many species of gram-negative and gram-positive bacteria. In(More)
Heparan sulfate is a sulfated glycan that exhibits essential physiological functions. Interrogation of the specificity of heparan sulfate-mediated activities demands a library of structurally defined oligosaccharides. Chemical synthesis of large heparan sulfate oligosaccharides remains challenging. We report the synthesis of oligosaccharides with different(More)
Heparan sulfate (HS) belongs to a major class of glycans that perform central physiological functions. Heparin is a specialized form of HS and is a clinically used anticoagulant drug. Heparin is a natural product isolated from pig intestine. There is a strong demand to replace natural heparin with a synthetic counterpart. Although a chemoenzymatic approach(More)
Quorum sensing (QS) is a bacterial cell-cell communication process by which bacteria communicate using extracellular signals called autoinducers. Two QS systems have been identified in Escherichia coli K-12, including an intact QS system 2 that is stimulated by the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex and a partial QS system 1 that consists(More)
Heparin has been the most commonly used anticoagulant drug for nearly a century. The drug heparin is generally categorized into three forms according to its molecular weight: unfractionated (UF, average molecular weight 13 000), low molecular weight (average molecular weight 5000) and ultra-low-molecular-weight heparin (ULMWH, average molecular weight(More)
Heparosan serves as the starting carbon backbone for the chemoenzymatic synthesis of heparin, a widely used clinical anticoagulant drug. The availability of heparosan is a significant concern for the cost-effective synthesis of bioengineered heparin. The carbon source is known as the pivotal factor affecting heparosan production. However, the mechanism by(More)
3′-Phosphoadenosine-5′-phosphosulfate (PAPS) is the obligate cosubstrate and source of the sulfonate group in the chemoenzymatic synthesis of heparin, a clinically used anticoagulant drug. Previously, we have developed a method to synthesize PAPS with Escherichia coli crude extracts, which include three overexpressed enzymes and a fourth unidentified(More)
In vitro digestibility, prebiotic activity and chemical composition of polysaccharides from rapeseed were deliberately studied in this paper. After preliminary treatments, two fractions of polysaccharides (RP1 and RP2) were obtained after purification by DEAE-cellulose and Sephadex G-100. Their primary structural feature and molecule weights were(More)
3′-Phosphoadenosine-5′-phosphosulfate (PAPS) is the obligate cosubstrate and source of the sulfonate group in the chemoenzymatic synthesis of heparin, a commonly used anticoagulant drug. Previously, using ATP as the substrate, we had developed a one-pot synthesis to prepare PAPS with 47% ATP conversion efficiency. During the reaction, 47% of ATP was(More)
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