A refined solution structure of hen lysozyme determined using residual dipolar coupling data

Schwalbe, H Grimshaw, SB Spencer, A Buck, M Boyd, J Dobson, CM Redfield, C Smith, LJ

H. Schwalbe et al., A refined solution structure of hen lysozyme determined using residual dipolar coupling data, PROTEIN SCI, 10(4), 2001, pp. 677-688

54

INGLESE

Article

Biochemistry & Biophysics

PROTEIN SCIENCE

0961-8368 → ACNP

10

4

2001

677 - 688

ISI

0961-8368(200104)10:4<677:ARSSOH>2.0.ZU;2-A

A high resolution NMR structure of hen lysozyme has been determined using 2 09 residual H-1-N-15 dipolar coupling restraints from measurements made in two different dilute liquid crystalline phases (bicelles) in conjunction wi th a data set of 1632 NOE distance restraints, 110 torsion angle restraints , and 60 hydrogen bond restraints. The ensemble of 50 low-energy calculated structures has an average backbone RMSD of 0.50+/-0.13 Angstrom to the mea n structure and of 1.49+/-0.10 Angstrom to the crystal structure of hen lys ozyme. To assess the importance of the dipolar coupling data in the structu re determination, the final structures are compared with an ensemble calcul ated using an identical protocol but excluding the dipolar coupling restrai nts. The comparison shows that structures calculated with the dipolar coupl ing data are more similar to the crystal structure than those calculated wi thout, and have better stereochemical quality. The structures also show imp roved quality factors when compared with additional dipolar coupling data t hat were not included in the structure calculations, with orientation-depen dent N-15 chemical shift changes measured in the bicelle solutions, and wit h T-1/T-2 values obtained from N-15 relaxation measurements. Analysis of th e ensemble of NMR structures and comparisons with crystal structures,N-15 r elaxation data, and molecular dynamics simulations of hen lysozyme provides a detailed description of the solution structure of this protein and insig hts into its dynamical behavior.