The catalytic core of an archaeal 2-oxoacid dehydrogenase multienzyme complex is a 42-mer protein assembly

DOI: 10.1111/j.1742-4658.2011.08461.x
PMID: 22188654

Authors: Nia L. Marrott (University of Bath) , Jacqueline J. T. Marshall (University of Bristol) , Dmitri I. Svergun (EMBL) , Susan J. Crennell (University of Bath) , David W. Hough (University of Bath) , Michael J. Danson (University of Bath) , Jean M. H. Van Den Elsen (University of Bath)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Febs Journal

State: Published (Approved)
Published: December 2011

Abstract: The dihydrolipoyl acyl-transferase (E2) enzyme forms the structural and catalytic core of the tripartite 2-oxoacid dehydrogenase multienzyme complexes of the central metabolic pathways. Although this family of multienzyme complexes shares a common architecture, their E2 cores form homo-trimers that, depending on the source, further associate into either octahedral (24-mer) or icosahedral (60-mer) assemblies, as predicted by the principles of quasi-equivalence. In the crystal structure of the E2 core from Thermoplasma acidophilum, a thermophilic archaeon, the homo-trimers assemble into a unique 42-mer oblate spheroid. Analytical equilibrium centrifugation and small-angle X-ray scattering analyses confirm that this catalytically active 1.08 MDa assembly exists as a single species in solution, forming a hollow spheroid with a maximum diameter of 220 Å. In this paper we show that a monodisperse macromolecular assembly, built from identical subunits in non-identical environments, forms an irregular protein shell via non-equivalent interactions. This unusually irregular protein shell, combining cubic and dodecahedral geometrical elements, expands on the concept of quasi-equivalence as a basis for understanding macromolecular assemblies by showing that cubic point group symmetry is not a physical requirement in multienzyme assembly. These results extend our basic knowledge of protein assembly and greatly expand the number of possibilities to manipulate self-assembling biological complexes to be utilized in innovative nanotechnology applications.

Journal Keywords: Binding; Catalytic; Crystallography; X-Ray; Models; Molecular; Multienzyme; Protein; Thermoplasma

Diamond Keywords: Enzymes; Archaea

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography , I04-Macromolecular Crystallography

Other Facilities: X33 at EMBL (DESY)

Added On: 09/01/2012 13:52

Discipline Tags:

Biochemistry Catalysis Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)