1L1M

SOLUTION STRUCTURE OF A DIMER OF LAC REPRESSOR DNA-BINDING DOMAIN COMPLEXED TO ITS NATURAL OPERATOR O1

SOLUTION NMR

NMR Experiment
Experiment	Type	Sample Contents	Solvent	Ionic Strength	pH	Pressure	Temperature (K)	Spectrometer
1	3D_13C-separated_NOESY	2mM Lac-HP62-V52C U-15N,13C, 10mM KPi, 20mM KCl, 90% H2O, 10% D2O	90% H2O/10% D2O	10mM KPi, 20mM KCl	6.0	ambient	315
2	3D_15N-separated_NOESY	2mM Lac-HP62-V52C U-15N,13C, 10mM KPi, 20mM KCl, 90% H2O, 10% D2O	90% H2O/10% D2O	10mM KPi, 20mM KCl	6.0	ambient	315
3	2D NOESY	2mM Lac-HP62-V52C U-15N,13C, 10mM KPi, 20mM KCl, 90% H2O, 10% D2O	90% H2O/10% D2O	10mM KPi, 20mM KCl	6.0	ambient	315

NMR Spectrometer Information
Spectrometer	Manufacturer	Model	Field Strength
1	Bruker	DRX	750
2	Bruker	DRX	600

NMR Refinement
Method	Details	Software
SIMULATED ANNEALING FOLLOWED BY RESTRAINED MDR	The structure of the complex was calculated as follows. First the structure of the dimeric lac HP62-V52C was calculated using only protein NMR restraints. The 50 best structures were selected and docked onto the natural lac operator B-DNA using simulated annealing. Distance and planarity restraints for the DNA were incorporated in order to keep DNA close to B-DNA but allowing a bend necessary to accommodate the two headpiece molecules on the DNA.	XwinNMR

NMR Ensemble Information
Conformer Selection Criteria	structures with the lowest energy
Conformers Calculated Total Number	100
Conformers Submitted Total Number	20
Representative Model	1 (closest to the average)

Additional NMR Experimental Information
Details	This structure was determined using standard 2D and 3D homo- and heteronuclearnuclear techniques. 13C-15N labeled protein was used and unlabeled nucleotide. IN ADDITION ISOTOPE FILTER EXPERIMENTS WERE APPLIED TO OBTAIN ADDITIONAL ASSIGNMENTS AND TO ASSIGN INTER-MOLECULAR NOES. FOR FURTHER DETAILS SEE THE REFERENCE DESCRIBING THE STRUCTURES.

Computation: NMR Software
#	Classification	Version	Software Name	Author
1	collection	XwinNMR	3.1	Bruker
2	processing	NMRPipe	1.0	Delaglio
3	data analysis	NMRView	5.0.4	Johnson
4	structure solution	CNS	1.1	Brunger
5	refinement	CNS	1.1	Brunger

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.