Yoko-o T, Tsukahara K, Watanabe T, Hata-Sugi N, Yoshimatsu K, Nagasu T, Jigami Y
National Institute of Bioscience and Human Technology, Higashi, Tsukuba, Japan.
FEBS Lett. 2001 Jan 26;489(1):75-80. doi: 10.1016/s0014-5793(01)02082-8.
The fission yeast Schizosaccharomyces pombe attaches an outer chain containing mannose and galactose to the N-linked oligosaccharides on many of its glycoproteins. We identified an S. pombe och1 mutant that did not synthesize the outer chains on acid phosphatase. The S. pombe och1(+) gene was a functional homolog of Saccharomyces cerevisiae OCH1, and its gene product (SpOch1p) incorporated alpha-1,6-linked mannose into pyridylaminated Man(9)GlcNAc(2), indicating that och1(+) encodes an alpha-1,6-mannosyltransferase. Our results indicate that SpOch1p is a key enzyme of outer chain elongation. The substrate specificity of SpOch1p was different from that of S. cerevisiae OCH1 gene product (ScOch1p), suggesting that SpOch1p may have a wider substrate specificity than that of ScOch1p.
裂殖酵母粟酒裂殖酵母会在其许多糖蛋白的N-连接寡糖上连接一条含有甘露糖和半乳糖的外链。我们鉴定出了一个粟酒裂殖酵母och1突变体，它不能在酸性磷酸酶上合成外链。粟酒裂殖酵母och1(+)基因是酿酒酵母OCH1的功能同源物，其基因产物（SpOch1p）将α-1,6-连接的甘露糖掺入到吡啶基化的Man(9)GlcNAc(2)中，这表明och1(+)编码一种α-1,6-甘露糖基转移酶。我们的结果表明SpOch1p是外链延伸的关键酶。SpOch1p的底物特异性与酿酒酵母OCH1基因产物（ScOch1p）不同，这表明SpOch1p可能比ScOch1p具有更广泛的底物特异性。
