Ohno K, Suzuki K
Department of Neurology, University of North Carolina, School of Medicine, Chapel Hill 27599-7250.
J Neurochem. 1988 Jan;50(1):316-8. doi: 10.1111/j.1471-4159.1988.tb13266.x.
Fibroblasts from a patient with GM2-gangliosidosis B1 variant contained mRNA of normal size but in reduced quantity for the beta-hexosaminidase alpha subunit. The nucleotide sequence of a cDNA clone that included the entire protein coding sequence was completely normal except for a single base substitution from G to A at no. 533, resulting in a change from arginine to histidine at amino acid no. 178. The same mutation was found in two other cDNA clones. The position of the mutation is approximately 90 amino acids from the N-terminus of the mature, processed enzyme. Computer analysis predicted substantial alterations in the secondary structure of the enzyme protein. These results provide new insight into functional domains of this enzyme.
一名患有GM2神经节苷脂沉积症B1变异型患者的成纤维细胞含有正常大小但β-己糖胺酶α亚基数量减少的mRNA。一个包含完整蛋白质编码序列的cDNA克隆的核苷酸序列完全正常，只是在第533位有一个从G到A的单碱基替换，导致第178位氨基酸从精氨酸变为组氨酸。在另外两个cDNA克隆中也发现了相同的突变。该突变位置距离成熟加工酶的N端约90个氨基酸。计算机分析预测该酶蛋白的二级结构会有显著改变。这些结果为该酶的功能域提供了新的见解。
