1dwm
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SOLUTION STRUCTURE OF LINUM USITATISSINUM TRYPSIN INHIBITOR (LUTI)
OverviewOverview
The solution structure of a novel 69 residue proteinase inhibitor, Linum, usitatissimum trypsin inhibitor (LUTI), was determined using a method, based on computer aided assignment of nuclear Overhauser enhancement, spectroscopy (NOESY) data. The approach applied uses the program, NOAH/DYANA for automatic assignment of NOESY cross-peaks. Calculations, were carried out using two unassigned NOESY peak lists and a set of, determined dihedral angle restraints. In addition, hydrogen bonds, involving amide protons were identified during calculations using, geometrical criteria and values of HN temperature coefficients., Stereospecific assignment of beta-methylene protons was carried out using, a standard procedure based on nuclear Overhauser enhancement intensities, and 3J(alpha)(beta) coupling constants. Further stereospecific assignment, of methylene protons and diastereotopic methyl groups were established, upon structure-based method available in the program GLOMSA and chemical, shift calculations. The applied algorithm allowed us to assign 1968 out of, 2164 peaks (91%) derived from NOESY spectra recorded in H2O and 2H2O. The, final experimental data input consisted of 1609 interproton distance, restraints, 88 restraints for 44 hydrogen bonds, 63 torsion angle, restraints and 32 stereospecifically assigned methylene proton pairs and, methyl groups. The algorithm allowed the calculation of a high precision, protein structure without the laborious manual assignment of NOESY, cross-peaks. For the 20 best conformers selected out of 40 refined ones in, the program CNS, the calculated average pairwise rmsd values for residues, 3 to 69 were 0.38 A (backbone atoms) and 1.02 A (all heavy atoms). The, three-dimensional LUTI structure consists of a mixed parallel and, antiparallel beta-sheet, a single alpha-helix and shows the fold of the, potato 1 family of proteinase inhibitors. Compared to known structures of, the family, LUTI contains Arg and Trp residues at positions P6' and P8', respectively, instead of two Arg residues, involved in the proteinase, binding loop stabilization. A consequence of the ArgTrp substitution at, P8' is a slightly more compact conformation of the loop relative to the, protein core.
About this StructureAbout this Structure
1DWM is a Single protein structure of sequence from Linum usitatissimum with ACE as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Determination of a high precision structure of a novel protein, Linum usitatissimum trypsin inhibitor (LUTI), using computer-aided assignment of NOESY cross-peaks., Cierpicki T, Otlewski J, J Mol Biol. 2000 Oct 6;302(5):1179-92. PMID:11183783
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