Small-angle neutron scattering reveals the assembly mode and oligomeric architecture of TET, a large, dodecameric aminopeptidase

Journal Article · Sat Nov 01 04:00:00 EDT 2014 · Acta Crystallographica. Section D: Biological Crystallography

DOI:https://doi.org/10.1107/S1399004714018446· OSTI ID:22347728

Appolaire, Alexandre; Girard, Eric; Colombo, Matteo; Durá, M. Asunción ^[1]; Moulin, Martine; Härtlein, Michael ^[2]; Franzetti, Bruno ^[1]; Gabel, Frank ^[1]

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1. Université Grenoble Alpes, IBS, 38044 Grenoble (France)
2. Institut Laue–Langevin, 38042 Grenoble CEDEX 9 (France)

The present work illustrates that small-angle neutron scattering, deuteration and contrast variation, combined with in vitro particle reconstruction, constitutes a very efficient approach to determine subunit architectures in large, symmetric protein complexes. In the case of the 468 kDa heterododecameric TET peptidase machine, it was demonstrated that the assembly of the 12 subunits is a highly controlled process and represents a way to optimize the catalytic efficiency of the enzyme. The specific self-association of proteins into oligomeric complexes is a common phenomenon in biological systems to optimize and regulate their function. However, de novo structure determination of these important complexes is often very challenging for atomic-resolution techniques. Furthermore, in the case of homo-oligomeric complexes, or complexes with very similar building blocks, the respective positions of subunits and their assembly pathways are difficult to determine using many structural biology techniques. Here, an elegant and powerful approach based on small-angle neutron scattering is applied, in combination with deuterium labelling and contrast variation, to elucidate the oligomeric organization of the quaternary structure and the assembly pathways of 468 kDa, hetero-oligomeric and symmetric Pyrococcus horikoshii TET2–TET3 aminopeptidase complexes. The results reveal that the topology of the PhTET2 and PhTET3 dimeric building blocks within the complexes is not casual but rather suggests that their quaternary arrangement optimizes the catalytic efficiency towards peptide substrates. This approach bears important potential for the determination of quaternary structures and assembly pathways of large oligomeric and symmetric complexes in biological systems.

• OSTI ID: 22347728
• Journal Information: Acta Crystallographica. Section D: Biological Crystallography, Journal Name: Acta Crystallographica. Section D: Biological Crystallography Journal Issue: Pt 11 Vol. 70; ISSN ABCRE6; ISSN 0907-4449
• Country of Publication: Denmark
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
DEUTERATION
DEUTERIUM
EFFICIENCY
IN VITRO
NEUTRON DIFFRACTION
POTENTIALS
RESOLUTION
SUBSTRATES
TOPOLOGY
VARIATIONS