Lajić S, Robins T, Krone N, Schwarz H P, Wedell A
Department of Molecular Medicine, CMM (L8:02), Karolinska Hospital, 17176 Stockholm, Sweden.
J Mol Med (Berl). 2001 Oct;79(10):581-6. doi: 10.1007/s001090100261.
We studied the functional and structural effects of two unique missense mutations in CYP21 found in patients with simple virilizing congenital adrenal hyperplasia. The rare variants L300F and V281G were found in two girls who were each hemizygous for one of the mutations. Functional analysis after expression in COS-1 cells revealed that the mutant enzymes had reduced enzymatic activity for conversion of both 17-hydroxyprogesterone (L300F 9.5%, V281G 3.9% of normal) and progesterone (L300F 4.4%, V281G 3.9% of normal). Both mutant enzymes had an increased degradation in mammalian COS-1 cells compared to the normal protein, although the L300F variant affected the degradation pattern to a greater extent. Our data indicate that the residue L300 is important in maintaining normal structure of the 21-hydroxylase enzyme whereas mutations affecting V281 most likely cause impaired enzyme activity by interfering with a specific function(s) of the protein.
我们研究了在单纯性男性化先天性肾上腺皮质增生症患者中发现的CYP21基因的两种独特错义突变的功能和结构效应。在两名女孩中发现了罕见的L300F和V281G变异，她们分别为其中一种突变的半合子。在COS-1细胞中表达后的功能分析显示，突变酶对17-羟孕酮（L300F为正常的9.5%，V281G为正常的3.9%）和孕酮（L300F为正常的4.4%，V281G为正常的3.9%）的转化酶活性降低。与正常蛋白相比，两种突变酶在哺乳动物COS-1细胞中的降解均增加，尽管L300F变异对降解模式的影响更大。我们的数据表明，L300残基对于维持21-羟化酶的正常结构很重要，而影响V281的突变很可能通过干扰蛋白质的特定功能而导致酶活性受损。
