1. The Crystal Structure of a Laminin G–like Module Reveals the Molecular Basis of α- Dystroglycan Binding to Laminins, Perlecan, and Agrin 
Erhard Hohenester, Dominic Tisi, Jan F. Talts, Rupert Timpl 
Molecular Cell 
Volume 4, Issue 5, Pages (November 1999)
DOI: /S (00)

2. Figure 1 Domain Structures of Laminin 2 and Agrin
Globular domains are represented by circles: LN, laminin NH2-terminal (domain VI); L4, laminin domain IV; LG, laminin G–like. Disulfide-rich domains are represented by ellipsoids: LE, laminin EGF–like; FS, follistatin-like; EG, EGF-like. Interchain disulfide bridges in laminin 2 are indicated by thick lines. The α1 chain in laminin 1 has the same domain structure as α2. A laminin-binding domain present at the NH2 terminus of chick agrin, but not rat agrin (Denzer et al. 1997), is represented by a hatched circle. Two splice sites in agrin are indicated by triangles (y and z in rat agrin; A and B in chick agrin).
Molecular Cell 1999 4, DOI: ( /S (00) )

3. Figure 2 The LG Module Structure
Stereo view of the α2LG5 module viewed approximately perpendicular to the β sandwich. β strands are labeled A–N. The disulfide bridge between Cys-3083 and Cys-3115 is in yellow, and the calcium ion is shown as a pink sphere. Figures 2, 3, 5, 6B were made with BOBSCRIPT (Kraulis 1991; Esnouf 1997) and RASTER3D (Merritt and Murphy 1994).
Molecular Cell 1999 4, DOI: ( /S (00) )

4. Figure 3 The Calcium Binding Site
Stereo view of the calcium binding site in α2LG5 in a similar view as Figure 2. The calcium ion is shown as a pink sphere. Residues coordinating to the calcium ion are labeled. Hydrogen bonds to the sulfate ion (see text) are shown as grey lines. A water molecule is also bound to the calcium ion but is not shown for clarity. The electron density shown is a difference Fourier map of the Sm derivative calculated with the final model phases and contoured at 10σ.
Molecular Cell 1999 4, DOI: ( /S (00) )

5. Figure 5 Alignment of LG Sequences
Structure-based sequence alignment: LAMA2, mouse laminin α2 chain (SwissProt Q60675); LAMA1, mouse laminin α1 chain (SwissProt P19137); AGRIN, rat agrin (SwissProt P25304). The sequence of human SAP is shown as well and has been aligned to α2LG5 according to a structural alignment by DALI (Holm and Sander 1994). Sequence numbers correspond to the mature polypeptide chains. In α2LG5, every tenth residue is marked by a dot, and secondary structure elements are indicated above the alignment. Residues coordinating to the calcium ion in α2LG5 are indicated by pink circles. Conserved core residues are shaded pink, conserved glycines, yellow, and cysteines, light blue. Basic regions implicated in ligand binding (see text) are underlined: dark blue in α2LG5, heparin, and α-DG binding; light blue in α1LG4, heparin, and α-DG binding; green in α1LG4, α-DG binding; red in agrin LG2, heparin binding. The insert at splice site z in agrin LG3 (see text) is indicated by a black box.
Molecular Cell 1999 4, DOI: ( /S (00) )

6. Figure 6 Ligand Binding Sites
(A) Electrostatic surface representation (Nicholls et al. 1991) of the α2LG5 structure. Positive and negative potential is represented by blue and red coloring, respectively, at the 10 kT level. The locations of residues involved in heparin and α-DG binding (see text) are indicated. The structure has been rotated by 90° about a horizontal axis relative to Figure 2.
(B) Stereo view of a Cα trace of the α2LG5 structure with basic residues underlined in Figure 5 mapped onto the structure and shown as colored Cα spheres: dark blue, heparin and α-DG binding in α2LG5 (Talts et al. 1999); light blue, heparin and α-DG binding in α1LG4 (Andac et al. 1999); green, α-DG binding in α1LG4 (Andac et al. 1999). The locations of splice sites y (A) in agrin LG2 and z (B) in agrin LG3 are indicated by red and black triangles, respectively. Selected loops are labeled.
Molecular Cell 1999 4, DOI: ( /S (00) )

7. Figure 4 Comparison of the LG Module and Pentraxin Folds
(A) α2LG5 and (B) human SAP (Emsley et al. 1994). Disulfide bridges are in yellow, and calcium ions are shown as pink spheres. The SAP subunit is viewed approximately down the 5-fold axis of the SAP pentamer. Regions involved in subunit contacts in the pentamer are indicated by the black arrows.
Molecular Cell 1999 4, DOI: ( /S (00) )