Burk S C, Papastavros M Z, McCormick F, Redfield A G
Department of Biochemistry, Brandeis University, Waltham, MA 02254.
Proc Natl Acad Sci U S A. 1989 Feb;86(3):817-20. doi: 10.1073/pnas.86.3.817.
A sample of Escherichia coli-expressed human N-RAS-encoded p21, a 21-kDa protein, was selectively labeled with 15N at each of the 14 glycine amide positions. Two-dimensional proton-observe 15N correlation spectra showed one peak for each glycine residue. Five glycine resonances were identified with residues near the nucleotide binding site and provide useful reporters of several oncogene-activating positions. Three of these resonances were assigned to residues 10, 15, and 115 from the spectrum of a sample that was also labeled with [13C]valine. These resonances showed extra splitting or broadening due to the 13C label, which could be eliminated by 13C decoupling. Two other peaks were unambiguously identified as Gly-12 and Gly-13 using a one-dimensional edited nuclear Overhauser experiment and by spectral comparison with an Asp-12 mutant. These assignments have provided several site-specific probes of critical domains in p21.
一份由大肠杆菌表达的人N-RAS编码的p21(一种21 kDa的蛋白质)样本,在14个甘氨酰胺位置上均被15N选择性标记。二维质子观测15N相关谱显示每个甘氨酸残基有一个峰。五个甘氨酸共振峰在核苷酸结合位点附近被鉴定出来,它们为几个致癌基因激活位点提供了有用的报告信号。其中三个共振峰从同样用[13C]缬氨酸标记的样本光谱中被指定为第10、15和115位残基。这些共振峰由于13C标记而显示出额外的分裂或展宽,通过13C去耦可以消除这种现象。使用一维编辑核Overhauser实验并通过与Asp-12突变体的光谱比较,另外两个峰被明确鉴定为Gly-12和Gly-13。这些归属为p21关键结构域提供了几个位点特异性探针。