Architectural accommodation in the complex of four p53 DNA binding domain peptides with the p21/waf1/cip1 DNA response element.
High resolution chemical footprinting and cross-linking experiments have provided a basis for elucidating the overall architecture of the complex between the core DNA binding domain of p53 (p53DBD, amino acids 98-309) and the p21/waf1/cip1 DNA response element implicated in the G1/S phase cell cycle checkpoint. These studies complement both a crystal structure and earlier biophysical studies and provide the first direct experimental evidence that four subunits of p53DBD bind to the response element in a regular staggered array having pseudodyad symmetry. The invariant guanosines in the highly conserved C(A/T)|(T/A)G parts of the consensus half-sites are critical to the p53DBD-DNA binding. Molecular modeling of the complex using the observed peptide-DNA contacts shows that when four subunits of p53DBD bind the response element, the DNA has to bend approximately 50 degrees to relieve steric clashes among different subunits, consistent with recent DNA cyclization studies. The overall lateral arrangement of the four p53 subunits with respect to the DNA loop comprises a novel nucleoprotein assembly that has not been reported previously in other complexes. We suggest that this kind of nucleoprotein superstructure may be important for p53 binding to response elements packed in chromatin and for subsequent transactivation of p53-mediated genes.
Nagaich
A K
AK
Department of Biochemistry/330, School of Medicine, University of Nevada Reno, Reno, Nevada 89557-0014, USA.
Zhurkin
V B
VB
Sakamoto
H
H
Gorin
A A
AA
Clore
G M
GM
Gronenborn
A M
AM
Appella
E
E
Harrington
R E
RE
D001483:Base Sequence; D001665:Binding Sites; D003198:Computer Simulation; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D019175:DNA Methylation; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D012984:Software; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism
D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D016159:Tumor Suppressor Protein p53; D004247:DNA