Biosynthetic incorporation of unnatural sialic acids into polysialic acid on neural cells
Biosynthetic incorporation of unnatural sialic acids into polysialic acid on neural cells
复制标题
DOI：
10.1093/glycob/10.10.1049
复制
发表时间：
2000-10-01
期刊：
影响因子：
4.3
通讯作者：
Bertozzi, CR
中科院分区：
文献类型：
--
作者：
Charter, NW;Mahal, LK;Bertozzi, CR
在这项研究中，我们证明了多唾液基转移酶能够在终末分化的人类神经元中接受非自然底物。聚唾液酸转移酶催化神经细胞粘附分子（NCAM）与聚唾液酸（PSA）的糖基化。天然唾液酸类似物n -左旋丙烯酰唾液酸（SiaLev）通过代谢前体n -左旋丙烯酰甘露胺（ManLev）培养神经元，将其掺入细胞表面糖缀合物，包括PSA，然后将SiaLev左旋丙烯酰侧链内的酮基用作生物素探针检测的化学柄。SiaLev残基与PSA的结合证明了唾液酸酶的保护作用，唾液酸酶可以切割天然唾液酸，但不能切割含有非天然n -酰基的唾液酸。SiaLev基团在神经元细胞表面的存在不会阻碍神经突起的生长，也不会显著影响PSA在神经元室的分布。由于PSA在神经的可塑性和发育中很重要，这种调节PSA结构的机制可能对功能研究有用。
In this study we demonstrate that polysialyltransferases are capable of accepting unnatural substrates in terminally differentiated human neurons. Polysialyltransferases catalyze the glycosylation of the neural cell adhesion molecule (NCAM) with polysialic acid (PSA). The unnatural sialic acid analog, N-levulinoyl sialic acid (SiaLev), was incorporated into cell surface glycoconjugates including PSA by the incubation of cultured neurons with the metabolic precursor N-levulinoylmannosamine (ManLev), The ketone group within the levulinoyl side chain of SiaLev was then used as a chemical handle for detection using a biotin probe. The incorporation of SiaLev residues into PSA was demonstrated by protection from sialidases that can cleave natural sialic acids but not those bearing unnatural N-acyl groups. The presence of SiaLev groups on the neuronal cell surface did not impede neurite outgrowth or significantly affect the distribution of PSA on neuronal compartments, Since PSA is important in neural plasticity and development, this mechanism for modulating PSA structure might be useful for functional studies.