Study on the mechanism of molecular recognition between the glycosyl transferase and the core-peptide controlling heparin biosynthesis

糖胺聚糖（GACs）分为具有不同性质的两类;肝素型和软骨素型。然而，第一个己糖胺残基将GAG分类为这两类的糖基转移机制尚不清楚。这一事实促使我们合成可直接用于酶促聚糖延伸的蛋白聚糖探针，以阐明分选机制。据我们所知，肝素型糖胺聚糖通常与核心肽的疏水区和邻近的酸性区相连。这表明第一个氨基己糖转移酶识别与特定肽协调的环境，以确定GAG的类别。因此，选择由GlcA-Gal-Gal-Xyl连接到疏水和酸性肽（β聚糖的部分序列）组成的四糖基寡肽作为待合成的目标化合物。本课题前期采用液相法合成了相应的四糖基六肽。采用固相支持合成法也得到了相同类型的化合物，其合成方案导致相应的四糖基十六肽的成功形成。本项目主要完成了目标糖基寡肽的合成，并建立了固相支持法合成蛋白多糖的方法。

Glycosaminoglycans (GACs) are classified into two categories having different properties; heparin-type and chondroitin-type. However, glycosyl transfer mechanisms of the first hexosamine residue sorting the GAG into these two categories, are unknown. This fact prompted us to synthesize the proteoglycan probe that could be directly used for the enzymatic glycan elongation in order to elucidate the sorting mechanisms. So far as we know, it has been appointed that the heparin-type of GAG often linked to the hydrophobic and the neighboring acidic regions of the core-peptide. This suggests that the first hexosaminyl transferase recognizes the environment coordinated with the specific peptides to determine the category of GAG. Thus, the tetraosyl oligopeptides composed of GlcA-Gal-Gal-Xyl linking to the hydrophobic and acidic peptides, a partial sequence of the betaglycan, have been selected as the targeted compound to be synthesized. At the beginning of the project, the corresponding tetraosyl hexapeptide was synthesized with liquid phase method. The same type compound was also obtained with the solid support synthesis, of which synthetic protocol led to the successful formation of the corresponding tetraosyl hexadecapeptide. Within the term of this project, the targeted glycosyl oligopeptides were synthesized and proteoglycan synthesis with solid support method was also established.