期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1990
卷号：87
期号：16
页码：6034-6038
DOI：10.1073/pnas.87.16.6034
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We report studies of the DNA complex formed by GCN4, a transcriptional activator of eukaryotic amino acid biosynthetic operons. The DNA thermodynamic binding domain, defined by primer extension analysis, spans at least 18 base pairs, a site much larger than the 9-base-pair consensus defined by homology with naturally occurring binding sites. Chemical modification experiments reveal multiple sites of protein-DNA contact: methylation of any guanine N-7 or adenine N-3, ethylation of any phosphate oxygen, or elimination of any nucleoside within a region spanning nearly one and a half turns of the double helix reduces the binding affinity of the complex measurably. Nevertheless, the protein yields no detectable hydroxyl radical footprint, implying that the minor groove is reagent-accessible in the protein-DNA complex. These chemical modification patterns indicate that GCN4 does not utilize any of the DNA-recognition motifs of paradigm DNA-binding proteins. Assays to detect DNA bending induced by truncated or intact GCN4 indicate that protein conformation and not a protein-induced bend is responsible for the anomalous electrophoretic behavior of GCN4-DNA complexes.
