Table 1.
Helical tilt angles of Ig-binding domains of Staphylococcal protein A
| α1/α2 | α1/3α | α2/α3 | |
| Z domain refined using CNS with RDC constraints | 169.5 ± 2.9 | 17.0 ± 3.4 | 172.2 ± 1.8 |
| Z domain refined using CNS without RDC constraints | 172.5 ± 4.1 | 10.2 ± 4.4 | 171.9 ± 2.2 |
| Z domain refined with RDC constraints from 2 alignment media | 171.4 ± 3.4 | 15.2 ± 3.9 | 172.3 ± 1.8 |
| Z domain reported previously (PDB ID: 2SPZ; Tashiro et al. 1997) | 170.2 ± 4.3 | 13.1 ± 2.9 | 173.4 ± 2.1 |
| B domain (PDB ID: 1BDC; Gouda et al. 1992) | 150.0 ± 2.4 | 39.7 ± 3.7 | 168.8 ± 2.8 |
| D domain in complex (PDB ID: 1DEE; Graille et al. 2000) | 174.2 | 14.6 | 168.2 |
| E domain (PDB ID: 1EDL: Starovasnik et al. 1996) | 166.0 ± 2.9 | 15.0 ± 4.3 | 168.1 ± 1.3 |
| Fc-bound B domain (PDB ID: 1EC2; Deisenhofer 1981) (helix α3 not observed) | 173.3 | — | — |
| Z domain in complex with affibody (PDB ID: 1LP1; Högbom et al. 2003) | 177.8 | 10.8 | 167.7 |
| Z domain in complex with affibody (PDB ID: 1H0T; Wahlberg et al. 2003) | 171.4 ± 1.7 | 18.2 ± 2.1 | 169.2 ± 1.9 |
Helical tilt angles were calculated from the X-ray structures (D domain and B domain in complex) or ensemble of NMR conformers using the program MOLMOL (Koradi et al. 1996). The helix locations for previously reported structures were taken from the papers describing these structures.