Ruiz-García A B, Sendra R, Pamblanco M, Tordera V
Departament de Bioquímica i Biologia Molecular, Universitat de València, Burjassot, Spain.
FEBS Lett. 1997 Feb 17;403(2):186-90. doi: 10.1016/s0014-5793(97)00049-5.
Enzymatic extracts from a gcn5 mutant and wild-type strains of Saccharomyces cerevisiae were chromatographically fractionated and the histone acetyltransferase activities compared. When free histones were used as substrate, extracts from wild-type cells showed two peaks of activity on histone H3 but extracts from gcn5 mutant cells showed only one. With nucleosomes as substrate, the histone acetyltransferase activities present in extracts from the gcn5 mutant strain were not able to modify H3 whereas wild-type cell extracts acetylated intensely this histone. The activity that acetylated nucleosome-bound H3 behaved as a 170-kDa complex. We suggest that Gcn5p represents a catalytic subunit within a multiprotein complex containing proteins that confer on it the ability to acetylate H3 in nucleosomes.
对酿酒酵母gcn5突变体和野生型菌株的酶提取物进行色谱分级分离,并比较组蛋白乙酰转移酶活性。当使用游离组蛋白作为底物时,野生型细胞提取物在组蛋白H3上显示出两个活性峰,但gcn5突变体细胞提取物仅显示出一个。以核小体作为底物时,gcn5突变体菌株提取物中的组蛋白乙酰转移酶活性无法修饰H3,而野生型细胞提取物则强烈乙酰化该组蛋白。使结合核小体的H3乙酰化的活性表现为一种170 kDa的复合物。我们认为,Gcn5p代表一种多蛋白复合物中的催化亚基,该复合物中的蛋白质赋予其乙酰化核小体中H3的能力。