Structural Specificity of Heparan Sulfate for Herpes Infections

硫酸乙酰肝素是一种高度硫酸盐化的多糖，具有非常复杂的糖结构。肝素 硫酸盐大量存在于细胞表面和细胞外基质中，起着重要的作用 在广泛的生理和病理生理功能中发挥作用。我们建议理解 特定的磺化糖序列对协助单纯疱疹病毒感染的贡献。这个 硫酸乙酰肝素与单纯疱疹病毒包膜蛋白的结合代表了病毒感染的第一步 感染。最近的研究表明，一种特殊的3-O-硫酸乙酰肝素在 协助单纯疱疹病毒1型进入。这种独特的硫酸肝素亚型是由 几种硫酸乙酰肝素3-0-磺基转移酶异构体(3-OST)。我们计划对这起案件进行调查 3-OST的识别机制。我们还将研究如何制备多糖或 具有独特磺化模式的寡糖提高抑制疱疹的有效性和选择性 单纯性感染。该项目提出了三个具体目标：具体目标1是调查 3-OST的底物识别机制。我们计划对3-OST-5和 定点突变。第二，我们计划转化3-OST-1，一种不产生HSV的酶 进入受体，通过随机诱变产生HSV进入受体的3-OST-3样酶。 具体目标2是开发一种酶促方法来合成八糖和多糖， 携带关键的3-0-磺基氨基葡萄糖残留物。我们最近的数据表明，这种方法使我们能够 合成足够量的多糖以研究其抑制单纯疱疹病毒的作用 病毒感染。具体目标3是确定合成化合物的抑制效果。 单纯疱疹病毒感染。我们计划确定它们对条目的影响以及对 单纯疱疹病毒传播到靶细胞。我们还计划研究这些化合物对心脏疾病的疗效。 单纯疱疹病毒通过不同的细胞受体进入。我们的结果可能会导致一种新的方法来 治疗单纯疱疹病毒感染，提高对HS生物合成的基本认识 特定的磺化模式。

Heparan sulfate is a highly sulfated polysaccharide with very complicated saccharide structures. Heparan sulfate is present on the cell surface and in the extracellular matrix in a large quantity, and plays important roles in a wide range of physiological and pathophysiological functions. We propose to understand the contribution of specific sulfonated saccharide sequences to assist herpes simplex virus infections. The binding of heparan sulfate to the herpes simplex virus envelope proteins represents the initial step of viral infections. Recent studies reveal that a specific 3-O-sulfated heparan sulfate plays an essential role for assisting the entry of herpes simplex virus 1. This unique subtype of heparan sulfate is biosynthesized by several heparan sulfate 3-0-sulfotransferase isoforms (3-OST). We plan to investigate the susbtrate recognition mechanism of 3-OST. We will also investigate how to prepare the polysaccharides or oligosaccharides with unique sulfonation patterns to improve the efficacy and slectivity for inhibiting herpes simplex infections. Three specific aims are proposed in this project: Specific Aim 1 is to investigate the substrate recognition mechanism of 3-OST. We plan to conduct a crystal structure study on 3-OST-5 and site-directed mutagenesis. Second, we plan to convert 3-OST-1, an enzyme that does not produce an HSV entry receptor, to a 3-OST-3-like enzyme that generates an HSV entry receptor by random mutagenesis. Specific Aim 2 is to develop an enzymatic approach to synthesize octasaccharides and polysaccharides that carry the critical 3-0-sulfo glucosamine residues. Our recent data suggest that this approach allows us to synthesize the polysaccharides in sufficient amounts for studying their effects on inhibiting herpes simplex virus infections. Specific Aim 3 is to determine the efficacy of the synthesized compounds on inhibitng herpes simplex infections. We plan to determine their effects on the entry as well as on the binding of herpes simplex virus to the target cells. We also plan to investigate the efficacy of these compounds on the entry of herpes simplex virus via different cellular receptors. Our results could lead to a novel approach to treat herpes simplex virus infections and improve the basic understanding on the biosynthesis of HS with specific sulfonation patterns.