X-ray structure refinement and comparison of three forms of mitochondrial aspartate aminotransferase.McPhalen, C.A., Vincent, M.G., Jansonius, J.N.
(1992) J.Mol.Biol. 225: 495-517
- PubMed: 1593633
- Primary Citation of Related Structures:
- PubMed Abstract:
- Three-Dimensional Structure of a Pyridoxal-Phosphate-Dependent Enzyme, Mitochondrial Aspartate Aminotransferase
Ford, G.C.,Eichele, G.,Jansonius, J.N.
(1980) Proc.Natl.Acad.Sci.USA 77: 2559
- The Open(Slash)Closed Conformational Equilibrium of Aspartate Aminotransferase: Studies in the Crystalline State and with a Fluorescent Probe in Solution
Picot, D.,Sandmeier, E.,Thaller, C.,Vincent, M.G.,Christen, P.,Jansonius, J.N.
(1991) Eur.J.Biochem. 196: 329
- Mechanism of Action of Aspartate Aminotransferase Proposed on the Basis of its Spatial Structure
Kirsch, J.F.,Eichele, G.,Ford, G.C.,Vincent, M.G.,Jansonius, J.N.,Gehring, H.,Christen, P.
(1984) J.Mol.Biol. 174: 497
The X-ray crystal structures of three forms of the enzyme aspartate aminotransferase (EC 22.214.171.124) from chicken heart mitochondria have been refined by least-squares methods: holoenzyme with the co-factor pyridoxal-5'-phosphate bound at pH 7.5 (1.9 A ...
The X-ray crystal structures of three forms of the enzyme aspartate aminotransferase (EC 126.96.36.199) from chicken heart mitochondria have been refined by least-squares methods: holoenzyme with the co-factor pyridoxal-5'-phosphate bound at pH 7.5 (1.9 A resolution), holoenzyme with pyridoxal-5'-phosphate bound at pH 5.1 (2.3 A resolution) and holoenzyme with the co-factor pyridoxamine-5'-phosphate bound at pH 7.5 (2.2 A resolution). The crystallographic agreement factors [formula: see text] for the structures are 0.166, 0.130 and 0.131, respectively, for all data in the resolution range from 10.0 A to the limit of diffraction for each structure. The secondary, super-secondary and domain structures of the pyridoxal-phosphate holoenzyme at pH 7.5 are described in detail. The surface area of the interface between the monomer subunits of this dimeric alpha 2 protein is unusually large, indicating a very stable dimer. This is consistent with biochemical data. Both subunit and domain interfaces are relatively smooth compared with other proteins. The interactions of the protein with its co-factor are described and compared among the three structures. Observed changes in co-factor conformation may be related to spectral changes and the energetics of the catalytic reaction. Small but significant adjustments of the protein to changes in co-factor conformation are seen. These adjustments may be accommodated by small rigid-body shifts of secondary structural elements, and by packing defects in the protein core.
Department of Structural Biology, University of Basel, Switzerland.