Protein flexibility directs DNA recognition by the papillomavirus E2 proteins.
Although DNA flexibility is known to play an important role in DNA-protein interactions, the importance of protein flexibility is less well understood. Here, we show that protein dynamics are important in DNA recognition using the well-characterized human papillomavirus (HPV) type 6 E2 protein as a model system. We have compared the DNA binding properties of the HPV 6 E2 DNA binding domain (DBD) and a mutant lacking two C-terminal leucine residues that form part of the hydrophobic core of the protein. Deletion of these residues results in increased specific and non-specific DNA binding and an overall decrease in DNA binding specificity. Using (15)N NMR relaxation and hydrogen/deuterium exchange, we demonstrate that the mutation results in increased flexibility within the hydrophobic core and loop regions that orient the DNA binding helices. Stopped-flow kinetic studies indicate that increased flexibility alters DNA binding by increasing initial interactions with DNA but has little or no effect on the structural rearrangements that follow this step. Taken together these data demonstrate that subtle changes in protein dynamics have a major influence on protein-DNA interactions.
School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK.
Craig
C
Brown
Karen
K
Campos-León
Madeleine
M
Strickland
Christopher
C
Williams
Victoria
V
Fairweather
R Leo
RL
Brady
Matthew P
MP
Crump
Kevin
K
Gaston
D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D052163:Human papillomavirus 6; D008958:Models, Molecular; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D014764:Viral Proteins; D004247:DNA