1ZY6

Membrane-bound dimer structure of Protegrin-1 (PG-1), a beta-Hairpin Antimicrobial Peptide in Lipid Bilayers from Rotational-Echo Double-Resonance Solid-State NMR

SOLID-STATE NMR

NMR Experiment
Experiment	Type	Sample Contents	Solvent	Ionic Strength	pH	Pressure	Temperature (K)	Spectrometer
1	rotational-echo double resonance (REDOR) NMR technique, which measures distances between heteronuclear spins	1:1 molar mixture of [13C-Cys15] PG-1 and [15N-Cys15] PG-1	POPC bilayers at a peptide-lipid molar ratio of 1:20			ambient	233
2	rotational-echo double resonance (REDOR) NMR technique, which measures distances between heteronuclear spins	[4-19F-Phe12, 13C-Val16] PG-1	POPC bilayers at a peptide-lipid molar ratio of 1:12.5			ambient	233

NMR Spectrometer Information
Spectrometer	Manufacturer	Model	Field Strength
1	Bruker	DSX 400	400

NMR Refinement
Method	Details	Software
Distance geometry; Simulated annealing	Two-spin REDOR curves were simulated using a Fortran program. Three-spin REDOR curves for the C -F experiment were simulated using the SIMPSON program. The input distances and angles in the three-spin simulation were obtained from model building. The simulations assumed delta-function pulses for all pi pulses. Models that were potentially consistent with all the experimentally measured distances were created using MODELLER. In addition to the REDOR-based restraints, the input file included a restraint to preserve the intramolecular hydrogen bond ladder of each monomer, and a restraint to maintain monomer symmetry.	SIMPSON

NMR Ensemble Information
Conformer Selection Criteria	least violations
Conformers Calculated Total Number	100
Conformers Submitted Total Number	1

Additional NMR Experimental Information
Details	Solid State NMR was performed at 400.49 MHz for 1H, 376.8 MHz for 19F, 100.72 MHz for 13C, and 40.58 MHz for 15N. The 15N{13C} and 13C{1H} REDOR experiments were carried out on a 1H/13C/15N triple resonance MAS probe. Spinning speeds were regulated to 3 Hz using a pneumatic control unit. 13C and 15N chemical shifts were referenced externally to the 13C signal of alpha-Gly at 176.4 ppm on the TMS scale and the 15N signal of N-acetyl-valine at 122 ppm, respectively. The 13C{19F} REDOR experiments, where the nucleus in the bracket is the unobserved dephasing spin, was conducted on a 4-mm magic-angle spinning (MAS) probe equipped with a Bruker HFX unit, which allows simultaneous tuning of 1H and 19F on the 1H channel.

Additional NMR Experimental Information

Details

Solid State NMR was performed at 400.49 MHz for 1H, 376.8 MHz for 19F, 100.72 MHz for 13C, and 40.58 MHz for 15N. The 15N{13C} and 13C{1H} REDOR experiments were carried out on a 1H/13C/15N triple resonance MAS probe. Spinning speeds were regulated to 3 Hz using a pneumatic control unit. 13C and 15N chemical shifts were referenced externally to the 13C signal of alpha-Gly at 176.4 ppm on the TMS scale and the 15N signal of N-acetyl-valine at 122 ppm, respectively. The 13C{19F} REDOR experiments, where the nucleus in the bracket is the unobserved dephasing spin, was conducted on a 4-mm magic-angle spinning (MAS) probe equipped with a Bruker HFX unit, which allows simultaneous tuning of 1H and 19F on the 1H channel.

Computation: NMR Software
#	Classification	Version	Software Name	Author
1	structure solution	SIMPSON		Bak, Rasmussen, Nielsen
2	refinement	MODELLER	6.1	Sali, Blundell

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.

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1ZY6

Membrane-bound dimer structure of Protegrin-1 (PG-1), a beta-Hairpin Antimicrobial Peptide in Lipid Bilayers from Rotational-Echo Double-Resonance Solid-State NMR