Find PDB structures and Computed Structure Models (CSM) by combining queries from tools in this suite: Attribute Search, Sequence Similarity, Sequence Motif, 3D Similarity, and 3D Motif with 'AND' logic.
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.