Multiple domains of repressor activator protein 1 contribute to facilitated binding of glycolysis regulatory protein 1.

Autor: López MC; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Box 100266, JHMHC, Gainesville, FL 32610-0266, USA., Smerage JB, Baker HV
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 1998 Nov 24; Vol. 95 (24), pp. 14112-7.
DOI: 10.1073/pnas.95.24.14112
Abstrakt: The function of repressor activator protein 1 (Rap1p) at glycolytic enzyme gene upstream activating sequence (UAS) elements in Saccharomyces cerevisiae is to facilitate binding of glycolysis regulatory protein 1 (Gcr1p) at adjacent sites. Rap1p has a modular domain structure. In its amino terminus there is an asymmetric DNA-bending domain, which is distinct from its DNA-binding domain, which resides in the middle of the protein. In the carboxyl terminus of Rap1p lie its silencing and putative activation domains. We carried out a molecular dissection of Rap1p to identify domains contributing to its ability to facilitate binding of Gcr1p. We prepared full-length and three truncated versions of Rap1p and tested their ability to facilitate binding of Gcr1p by gel shift assay. The ability to detect ternary complexes containing Rap1p.DNA. Gcr1p depended on the presence of binding sites for both proteins in the probe DNA. The DNA-binding domain of Rap1p, although competent to bind DNA, was unable to facilitate binding of Gcr1p. Full-length Rap1p and the amino- and carboxyl-truncated versions of Rap1p were each able to facilitate binding of Gcr1p at an appropriately spaced binding site. Under these conditions, Gcr1p displayed an approximately 4-fold greater affinity for Rap1p-bound DNA than for otherwise identical free DNA. When spacing between Rap1p- and Gcr1p-binding sites was altered by insertion of five nucleotides, the ability to form ternary Rap1p.DNA.Gcr1p complexes was inhibited by all but the DNA-binding domain of Rap1p itself; however, the ability of each individual protein to bind the DNA probe was unaffected.
Databáze: MEDLINE