Structure of the Globular Region of the Prion Protein Ure2 from the Yeast Saccharomyces cerevisiae  Luc Bousset, Hassan Belrhali, Joël Janin, Ronald Melki, Solange Morera  Structure  Volume 9, Issue 1, Pages 39-46 (January 2001) DOI: 10.1016/S0969-2126(00)00553-0

Figure 1 Ribbon Representation of the Three-Dimensional Structure of the Functional Region of Ure2p in Its Monomeric Form A short linker region, shown in yellow, separates the two domains. The cap region (residues 267–298) is shown in orange. The N-terminal domain (residues 95–196) consists of a central four-stranded β sheet (red) flanked on both sides by α helices (blue). The larger C-terminal domain (residues 206–354) is all α-helical. Drawn with MolScript [45] Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 2 Stereo View of the Electron Density Map at 2.5 Å Resolution around the Linker Region between the N- and C-Terminal Domains The map is calculated using SIGMAA-weighted 2Fo-Fc coefficients and is contoured at 1σ level [38]. The linker region is colored in yellow. Clear density is observed for all residues. Trp-202 is wedged between the two domains and is in contact with Gln-209, Ile-212, and Asn-213 from helix α5 on one side and with Leu-186, Val-189, and Asn-190 from helix α4 on the other. Ile-308 in helix α7 is also labeled Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 3 Stereo View of the Ure2p 95–354 Dimer The two monomers are differently colored. The central β sheet is in red. The 2-fold axis is in the plane of the drawing in (a), and orthogonal to it in (b) Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 4 Stereo View of the Superposition of the Ure2p Dimer and E. coli GST. Ure2p 95-354 is in blue, E .coli GST in purple. The cap region is the insertion of 32 residues (residues 267–298), located in the C-terminal domain of Ure2p 95-354 and shown in orange Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 5 Structure-Based Sequence Alignment of Ure2p 95-354 and Two Bacterial GSTs. The bacterial GSTs belong to the beta class: E. coli GST [17]; accession code 1a0f, and P. mirabilis GST [16]; accession code 2pmt. Secondary structure elements of Ure2p 95-354 are labeled and indicated by coils for α helices, arrows for β strands, and η for short 310 helices. Similar residues are in red and identical residues are shown as white letters on a red background. The positions of the catalytic tyrosine or serine residues of the eukaryotic classes of GSTs, and the catalytic cysteine and histidine residues of the beta class GSTs, are indicated by green stars. They are not conserved in Ure2p sequence. The figure was created using ESPript [46] Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 6 Structural Comparison of the Cap Region in Two Different Crystal Forms of Ure2p. Stereo diagram showing the superposition of the α carbon cap region for monomers C (blue) and D (red), from dimer CD of form I, and monomers A′ (yellow) and B′ (cyan), from dimer A′B′ of form II Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)

Figure 7 Ure2p Possess an Orphan Peptide Binding Site. (a) Surface of P. mirabillis GST (accession code 2pmt) with glutathione bound in the glutathione binding site. (b) Surface of Ure2p 95–354, showing its potential ligand binding site in the same orientation as in (a). The surface is colored according to the electrostatic potential. The figure was created using GRASP [47] Structure 2001 9, 39-46DOI: (10.1016/S0969-2126(00)00553-0)