Plasmid pIP501 encoded transcriptional repressor CopR: single amino acids involved in dimerization are also important for folding of the monomer

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Item Type:	Article
Title:	Plasmid pIP501 encoded transcriptional repressor CopR: single amino acids involved in dimerization are also important for folding of the monomer
Creators Name:	Steinmetzer, K., Kuhn, K., Behlke, J., Golbik, R. and Brantl, S.
Abstract:	CopR is one of the two components regulating replication of plasmid pIP501. It binds as a preformed dimer at the DNA major groove thereby repressing transcription of the essential repR-mRNA 10-20-fold. Previously, the DNA-binding motif was identified and the location of the dimeric interface was narrowed down. The C-terminal 29 residues were shown to be required exclusively for CopR stability. Here, we report the characterization of four single amino acid exchange mutants at the dimeric interface. All mutants were inactive in copy number control in vivo. Dimerization constants and DNA-binding constants were determined by analytical ultracentrifugation and EMSA, respectively. Denaturation experiments were performed to estimate the protein stability and to calculate ΔGH2O0. Our data indicate that the four analyzed amino acids are both involved in dimerization and proper folding of the monomer; i.e. they stabilize on the one hand the monomer and on the other hand the dimeric interface.
Keywords:	CD Measurements, CopR, Dimeric Interface, Plasmid PIP501, Plasmid Replication Control, Site-Directed Mutagenesis, Transcriptional Repressor
Source:	Plasmid
ISSN:	0147-619X
Publisher:	Elsevier / Academic Press
Volume:	47
Number:	3
Page Range:	201-209
Date:	1 January 2002
Official Publication:	https://doi.org/10.1016/S0147-619X(02)00002-1
PubMed:	View item in PubMed

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