A biaryl peptide crosslink in a MetJ peptide model confers cooperative, nonspecific binding to DNA that ablates both repressor binding and in vitro transcription.
The MetJ repressor is the archetypal example of the beta-ribbon-helix-helix DNA binding motif. A model of the MetJ beta-ribbon (residues 22-28) was prepared by forming a dityrosine crosslinked dimer from the heptapeptide KKYTVSI. Using SPR, the peptide dimer 2 was shown to bind to dsDNA under physiologically relevant conditions, whereas the monomeric peptide did not. The peptide dimer appeared to inhibit binding of the MetJ repressor to natural met operators. Based on the stoichiometry of binding, the binding of peptide dimer 2 seems both highly co-operative and to lack sequence specificity. Peptide binding also appears to prevent transcription in vitro.
Yoburn
Joshua C
JC
Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
Deb
Sipra
S
Manfield
Iain W
IW
Stockley
Peter G
PG
Van Vranken
David L
DL
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics*; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry
D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D010455:Peptides; D012097:Repressor Proteins; C060486:methionine repressor protein, Bacteria; D014443:Tyrosine; D004247:DNA; C007543:dityrosine