TABLE 2.

Summary of structure statistics for PLCγ₂ spPH

<SA> represents the set of 20 selected lowest energy conformers obtained by restrained dynamical simulated annealing in CNS. SA_lowest refers to the lowest energy structure of the set. There were no NOE (>0.4 Å) or dihedral (>5°) violations for any of the lowest energy conformers.

	<SA>	SAlowest
Experimental restraintsa
All (Å) (2487)	0.018 ± 0.002	0.014
Intraresidue (786)	0.014 ± 0.003	0.010
Sequential (553)	0.014 ± 0.005	0.010
Short (373)	0.023 ± 0.003	0.020
Long (766)	0.018 ± 0.001	0.015
Ambiguous (9)	0.009 ± 0.005	0.009
Hydrogen bond restraints (Å) (70)	0.031 ± 0.004	0.029
Dihedral angle restraints (degrees) (114)	0.26 ± 0.03	0.236
Deviations from idealized covalent geometryb
Bonds (Å) (1930)	0.0013 ± 0.0001	0.0012
Angles (degrees) (3490)	0.31 ± 0.004	0.31
Improper dihedrals (degrees) (1020)	0.2 ± 0.01	0.2
Structural statistics for the ensemblec
PROCHECK parameters
Most favored region (%)	73.1 ± 2.7	74.3
Additionally allowed (%)	22.5 ± 2.7	23.8
Generously allowed (%)	3.0 ± 1.6	1.0
Disallowed (%)	1.5 ± 0.7	1.0
Number of bad contacts	3 ± 2	1
Root mean square difference from the average structured
Backbone (N, Cα, C) (Å)	0.41 ± 0.05	0.34
Heavy atoms (Å)	0.76 ± 0.06	0.62

^aSum averaging of NOE distance restraints was used for groups with degenerate proton chemical shifts. The interproton unambiguous distance restraint list comprised 786 intraresidue, 553 sequential (|i - j| = 1|), 373 short range (1 < |i - j| < 5), and 776 long range (|i - j| > 5). Hydrogen bond restraints were applied as pairs of distance restraints: H^N···O, 1.2-2.2 Å; N···O, 1.2-3.2 Å. The final values for the respective force constants were as follows: NOE, 30 kcal mol⁻¹ Å⁻²; hydrogen bonds, 50 kcal mol⁻¹ Å⁻²; dihedral angles, 200 kcal mol⁻¹ rad⁻².

^bThe final values for the respective force constants were as follows: bond lengths, 1000 kcal mol⁻¹ Å⁻²; angles and improper torsions, 500 kcal mol⁻¹ rad⁻²; the improper torsion angle restraints serve to maintain planarity and chirality.

^cThe program PROCHECK (64) was used to assess the stereochemical parameters of the family of conformers for the spPH. The figures indicate the percentage of residues with backbone Φ and Ψ angles in separate regions of the Ramachandran plot, defined in the program. The number of bad contacts per 100 residues is expected to be in the range 0 - 30 for protein crystal structures of better than 3.0 Å resolution.

^dThe precision of the atomic coordinates is defined as the average pairwise root mean square difference between each of the 20 conformers and a mean coordinate structure SA generated by iterative best fit of the backbone atoms (N, C^α, and C) over residues 478 - 508 and 849 - 908 of PLCγ₂spPH (comprising the core secondary structure elements and omitting the flexible N and C termini and the disordered loop between β3 and β4), followed by coordinate averaging.