RESUMEN
Heparan sulfate (HS) and heparin are sulfated polysaccharides exhibiting diverse physiological functions. HS 6-O-sulfotransferase (6-OST) is a HS biosynthetic enzyme that transfers a sulfo group to the 6-OH position of glucosamine to synthesize HS with desired biological activities. Chemoenzymatic synthesis is a widely adopted method to obtain HS oligosaccharides to support biological studies. However, this method is unable to synthesize all possible structures due to the specificity of natural enzymes. Here, we report the use of an engineered 6-OST to achieve fine control of the 6-O-sulfation. Unlike wild type enzyme, the engineered 6-OST only sulfates the non-reducing end glucosamine residue. Utilizing the engineered enzyme and wild type enzyme, we successfully completed the synthesis of five hexasaccharides and one octasaccharide differing in 6-O-sulfation patterns. We also identified a hexasaccharide construct as a new anticoagulant drug candidate. Our results demonstrate the feasibility of using an engineered HS biosynthetic enzyme to prepare HS-based therapeutics.
Asunto(s)
SulfotransferasasRESUMEN
Prunus tomentosa seeds were researched for antioxidant and anti-inflammatory constituents. By activity-guided fractionation of P. tomentosa seed extract, six new dihydrobenzofuran neolignans, prunustosanans AI-IV (1-4) and prunustosanansides AI and AII (5 and 6), together with 10 known compounds (7-16) were isolated from bioactive fraction. The structures were determined by spectroscopic analyses, especially NMR, HRESIMS, and CD spectra. The antioxidant activity was greatest for 5, 10, and 12 against DPPH radical and for 8, 9, and 13 against ABTS radical. Moreover, compounds 7 and 11 exhibited much stronger inhibitory activity on nitric oxide (NO) production in murine microglia BV-2 compared with positive control minocycline (IC50 = 19.7 ± 1.5 µM). The results show that P. tomentosa seeds can be regarded as a potential source of antioxidants and inflammation inhibitors.