Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography.
The decameric human erythrocyte protein torin is identical to the thiol-specific antioxidant protein-II (TSA-II), also termed peroxiredoxin-II (Prx-II). Single particle analysis from electron micrographs of Prx-II molecules homogeneously orientated across holes in the presence of a thin film of ammonium molybdate and trehalose has facilitated the production of a >/=20 A 3-D reconstruction by angular reconstitution that emphasises the D5 symmetry of the ring-like decamer. The X-ray structure for Prx-II was fitted into the transmission electron microscopic reconstruction by molecular replacement. The surface-rendered transmission electron microscopy (TEM) reconstruction correlates well with the solvent-excluded surface of the X-ray structure of the Prx-II molecule. This provides confirmation that transmission electron microscopy of negatively stained specimens, despite limited resolution, has the potential to reveal a valid representation of surface features of protein molecules. 2-D crystallisation of the Prx-II protein on mica as part of a TEM study resulted in the formation of a p2 crystal form with parallel linear arrays of stacked rings. This latter 2-D form correlates well with that observed from the 2.7 A X-ray structure of Prx-II solved from a new orthorhombic 3-D crystal form.
Harris
J R
JR
Institute of Zoology, University of Mainz, Germany. rharris@web.de
Schröder
E
E
Isupov
M N
MN
Scheffler
D
D
Kristensen
P
P
Littlechild
J A
JA
Vagin
A A
AA
Meissner
U
U
D018360:Crystallography, X-Ray; D004912:Erythrocytes / Q000737:chemistry; D006801:Humans; D008854:Microscopy, Electron; D008958:Models, Molecular; D008982:Molybdenum; D010544:Peroxidases / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D054464:Peroxiredoxins; D013499:Surface Properties; D014199:Trehalose
D008982:Molybdenum; D014199:Trehalose; D010544:Peroxidases; D054464:Peroxiredoxins; C022175:ammonium molybdate