PDBsum entry 1ozu

Oxidoreductase

PDB id: 1ozu

Contents

Protein chains

150 a.a. *

127 a.a. *

Ligands

SO4 ×2

Metals

_ZN ×3

Waters ×247

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Amyloid-Like filaments and water-Filled nanotubes formed by sod1 mutant proteins linked to familial als.

Authors

J.S.Elam, A.B.Taylor, R.Strange, S.Antonyuk, P.A.Doucette, J.A.Rodriguez, S.S.Hasnain, L.J.Hayward, J.S.Valentine, T.O.Yeates, P.J.Hart.

Ref.

Nat Struct Biol, 2003, 10, 461-467. [DOI no: 10.1038/nsb935]

PubMed id

12754496

Abstract

Mutations in the SOD1 gene cause the autosomal dominant, neurodegenerative disorder familial amyotrophic lateral sclerosis (FALS). In spinal cord neurons of human FALS patients and in transgenic mice expressing these mutant proteins, aggregates containing FALS SOD1 are observed. Accumulation of SOD1 aggregates is believed to interfere with axonal transport, protein degradation and anti-apoptotic functions of the neuronal cellular machinery. Here we show that metal-deficient, pathogenic SOD1 mutant proteins crystallize in three different crystal forms, all of which reveal higher-order assemblies of aligned beta-sheets. Amyloid-like filaments and water-filled nanotubes arise through extensive interactions between loop and beta-barrel elements of neighboring mutant SOD1 molecules. In all cases, non-native conformational changes permit a gain of interaction between dimers that leads to higher-order arrays. Normal beta-sheet-containing proteins avoid such self-association by preventing their edge strands from making intermolecular interactions. Loss of this protection through conformational rearrangement in the metal-deficient enzyme could be a toxic property common to mutants of SOD1 linked to FALS.

Figure 2.
Figure 2. GOI interfaces in pathogenic SOD1 give rise to cross- fibrils in two different crystal systems. (a) Orthogonal views of the linear, amyloid-like filaments represented by three dimers shown from top to bottom in green, gold and blue, respectively. Both the S134N and apo H46R linear filaments are represented by the single filament shown in panels i -iv. The GOI interface is red in the filament in i and boxed in ii -iv. In iv, which is rotated 90° relative to ii and iii, -strands 1, 2, 3 and 6, comprising one-half of each SOD1 -barrel, are shown in red. The 'cross- ' structure observed in amyloid fibrils is shown schematically in v. (b) Stereo view of the GOI interface in the S134N filament. Residues 125 -131 of the electrostatic loop from one S134N dimer (orange) interact with a depression in the -barrel of a neighboring S134N dimer (green) in the crystal lattice. Water molecules are represented as black spheres. The 1.3 Å [A]^55-weighted electron density, with coefficients 2mF[o] - DF[c], is contoured at 1.0 . (c) Small hydrophobic core formed at the GOI interface in the linear, pathogenic SOD1 filaments (see text). The image is an enlargement of the region boxed in image iii of panel a.

Figure 4.
Figure 4. Gain-of-interaction in Zn -H46R SOD1 giving rise to water-filled helical filaments. (a) One-half of the helical Zn -H46R filament, shown in i and ii, is represented by the two dimers shown from top to bottom in green and gold. Image ii is related to the left half of iii by a rotation of 90°. A schematic diagram of the tubular filament is shown in iv. In iii, the approximate location of the crystallographic two-fold axis that runs along the diagonal in the tetragonal unit cell is indicated by a black line without arrows and a 180° rotation symbol. Application of this two-fold operator generates one complete turn of the helical filament. The double-headed black arrow indicates the diameter of the helical filament, and the blue arrow indicates the diameter of the central cavity. The GOI interface between Zn -H46R dimers is boxed. In iii, -strands 1, 2, 3 and 6, which form one-half of each SOD1 -barrel, are shown in red. The zinc loop forms a short -strand (blue) that reciprocally adds to this -sheet in neighboring Zn -H46R dimers, stabilizing the GOI interface. Zinc ions are shown as purple spheres. (b) Stereo view of the GOI interface in the Zn -H46R helical filament. Residues 78 -81 of the zinc loop from one Zn -H46R dimer (orange) interact with an exposed edge of a -strand in a neighboring Zn -H46R dimer (green) in the crystal and vice versa. Zinc ions are represented as purple spheres. The 2.15 Å [A]^55-weighted electron density, with coefficients 2mF[o] - DF[c], is contoured at 1.0 . Water molecules have been omitted for clarity. (c) Stereo view of two turns of the helical filament generated by repetition of the GOIs in the Zn -H46R structure. This view of the helical filament is rotated 90° around a horizontal axis relative to images iii and vi of panel a. Successive Zn -H46R dimers (green, yellow, blue and red) comprise one turn of the helical filament with a pitch of 35 Å.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Biol (2003, 10, 461-467) copyright 2003.