1. Volume 8, Issue 3, Pages 633-644 (September 2001)
The Structure of Calnexin, an ER Chaperone Involved in Quality Control of Protein Folding 
Joseph D. Schrag, John J.M. Bergeron, Yunge Li, Svetlana Borisova, Michael Hahn, David Y. Thomas, Miroslaw Cygler 
Molecular Cell 
Volume 8, Issue 3, Pages (September 2001)
DOI: /S (01)

2. Figure 1 Stereo Views of the Experimental Electron Density
(A) Electron density derived from the combined MIRAS/SAS map in the globular domain. The map is contoured at the 1σ level. The Cα trace of the current model is also shown. Only a section of the lectin domain is shown for clarity, but the β strands are readily apparent.
(B) Electron density in the P domain contoured at the 1σ level. The crystal contacts between the last repeat of the P domain and the lectin domains of symmetry-related molecules are shown. The Cα trace of the current model of the P domain is also shown
Molecular Cell 2001 8, DOI: ( /S (01) )

3. Figure 2 Overall Structure of the Lumenal Domain of Calnexin
(A) Ribbon diagram showing the concave β sheet of the lectin domain in front and the convex β sheet in back. The ribbon is colored according to the average B factor for the residue. This figure was produced using Swiss PDB Viewer version 3.7 (Guex and Peitsch, 1997) and POVRAY (
(B) Schematic representation of the calnexin fold. Secondary structural elements are labeled. Residue numbers for secondary structural elements can be derived by comparison with Figure 3. This figure was produced using TOPS (Westhead et al., 1998)
Molecular Cell 2001 8, DOI: ( /S (01) )

4. Figure 3
Amino Acid Sequence Alignment of Representative Sequences of Calnexin, Calmegin, and Calreticulin
Sequences shown are canine calnexin, human calmegin (SWISS-PROT accession number O14967), and rat calreticulin (SWISS-PROT accession number P18418). Only the lumenal domain of calnexin is represented. Secondary structure assignments based on Kabsch and Sander (1983) are shown above the sequence (b = β strand; h = α helix). The motif 2 repeats are numbered according to the motif 1 repeat with which they interact. The carats (→) indicate the isoleucine residues which form short β strands. The residues conserved in at least 16 out of 18 sequences of orthologous and paralogous calnexins, calreticulins, and calmegins are shown in blue. Residues shown in magenta are residues conserved in type in at least 16 of the 18 aligned sequences. Residues in the following groups were considered to be equivalent in this assignment: E, D; K, R, H; A, G; I, L, V; Y, F, W; N, Q; S, T; M, C, P
Molecular Cell 2001 8, DOI: ( /S (01) )

5. Figure 4
Stereo View of the Electron Density around the Glucose Binding Site
Experimental density from the combined MIRAS/SAS/MAD map contoured at 1σ is shown in blue. In magenta is the 3Fsoak-2Fnat difference density corresponding to the bound glucose molecule, contoured at 2.5σ
Molecular Cell 2001 8, DOI: ( /S (01) )

6. Figure 5 Locations of Strongly Conserved Residues in the Lectin Domain
The strongly conserved residues (highlighted in blue in Figure 3) are marked with blue spheres. The putative Ca2+ ion is shown in orange and the glucose in violet. Residue numbers are provided for reference. Residues 76 and 120, which appear in this figure to contribute to the Ca2+ binding site, contribute instead to the hydrophobic core between β sheets
Molecular Cell 2001 8, DOI: ( /S (01) )

7. Figure 6 Structure of Tandem Sequence Repeats
(A) Structure of tandem repeat 3 with sequence motif 1 (residues 313–329) shown in light blue and motif 2 (residues 368–381) in dark blue. The side chains of residues which are conserved in all repeats (highlighted in blue in Figure 3) are shown and, except for Lys320, labeled. Lys320 lies behind Trp324 in this view. Dashed lines show antiparallel β hydrogen bonds between isoleucine residues.
(B) Superposition of four tandem repeat modules. The color coding of residues is indicated.
(C) Superposition of the calnexin module 4 repeat with the terminal repeat of the P domain of calreticulin (Protein Data Bank ID code 1HHN; model 4, which is designated as the most representative structure [Ellgaard et al., 2001]). This figure was made using MOLSCRIPT (Kraulis, 1991) and Raster 3D (Merritt and Murphy, 1994; Merritt and Bacon, 1997)
Molecular Cell 2001 8, DOI: ( /S (01) )

8. Figure 7 Crystal Packing Interactions
The arm of one calnexin monomer (green) wraps around the lectin domain of a symmetry-related molecule (blue). Residues that make crystal contacts are red. These residues are Lys135 and residues 173–178 in the lectin domain and Trp343 and residues 346–349 in the arm. The glucose molecule is violet, and the modeled positions of three mannose residues are shown in magenta. The disulfide bonds are yellow, and the putative Ca2+ ion is orange. The P domain of the monomer depicted in blue wraps around the lectin domain of the green monomer and is truncated for clarity. This figure was produced using SETOR (Evans, 1993)
Molecular Cell 2001 8, DOI: ( /S (01) )