THE 3-DIMENSIONAL STRUCTURE OF ACYL-COENZYME A BINDING-PROTEIN FROM BOVINE LIVER - STRUCTURAL REFINEMENT USING HETERONUCLEAR MULTIDIMENSIONAL NMR-SPECTROSCOPY

The 3D structure of bovine recombinant acyl-coenzyme A binding protein has been determined using multidimensional heteronuclear magnetic res onance spectroscopy in a study that combines investigations of N-15-la beled and unlabeled protein. The present structure determination is a refinement of the structure previously determined (Andersen, K.V. and Poulsen, F.M. (1992) J. Mol. Biol., 226, 1131 1141). It is based on 10 96 distance restraints and 124 dihedral angle restraints of which 69 a re for phi-angles and 8 for chiral centers and 47 for prochiral center s. The new experimental input for the structure determination has prov ided an increase of 263 distance restraints, 5 phi-angle restraints, a nd 32 chi-angle restraints in 2 chiral centers, and 31 prochiral cente rs restraining an additional 23 chi1, 8 chi2, and 1 chi3 angles. The i ncrease of 300 distance and dihedral angle restraints representing an additional 30% of input parameters for the structure determination has been shown to be in agreement with the first structure. A set of 29 s tructures has been calculated and each of the structures has been comp ared to a mean structure to give an atomic root mean square deviation of 0.44 +/- 0.12 angstrom (1 angstrom is 0. 1 nm) for the backbone ato ms C, C(alpha), and N in the four alpha-helices A1, residues 4-15, A2, residues 21 36, A3, residues 51 62 and A4, residues 65-84. The loop-r egion of residues Gly45-Lys50 could not be defined by the restraints o btained by NMR. The program PRONTO has been used for the spectrum anal ysis, assignment of the individual nuclear Overhauser effects, the int egration of the cross peaks, and the measurement of the coupling const ants. The programs DIANA, X-PLOR and INSIGHT have been used in the str ucture calculations and evaluations.