Table 2.
Properties of crystal packing contact surfaces of insulin hexamers in seven different space groups.
| Protein | C2urea | C2scn | C2221urea | C2221scn | 1EVR [11] | 1EV3 [11] | 1MSO [9] | 1TRZ [17] | nph-insc |
| Space group | C2 | C2 | C2221 | C2221 | P21 | R3 | R3 | R3 | P43212 |
| B-chain configuration | R6 | R6 | R6 | R6 | R6 | R6 | T6 | T3R3f | R6 |
| pH | 7.0 | 7.0 | 6.5 | 6.5 | 6.7 | 8.5 | 6.3 | 6.4 | 7.3 |
| Solvent content. (%) | 50 | 50 | 64 | 64 | 49 | 40 | 36 | 48 | |
| Avg B-factor | |||||||||
| protein atoms (Å2) | 25.5 | 19.5 | 32.1 | 33.5 | 41.1 | 30.2 | 12.0 | 32.8 | 34.8 |
| exposed atoms (Å2) | 27.9 | 21.5 | 34.0 | 35.9 | 42.5 | 34 | 12.3 | 34.7 | 36.5 |
| contact atoms (Å2) | 25.0 | 17.6 | 26.4 | 29.1 | 41.9 | 35.8 | 14.1 | 37.2 | 34.3 |
| Tot SASA (Å2)a | 14546 | 14478 | 40059 | 41532 | 15245 | 13573 | 13689 | 13904 | 15067 |
| Acont(Å2)b | 2117 | 2226 | 4269 | 4060 | 2113 | 2006 | 3313 | 2438 | 2279 |
| fract of tot SASA (%) | 14.6 | 15.4 | 10.6 | 9.8 | 13.9 | 14.8 | 24.2 | 17.5 | 15.1 |
| Atom type specific area as a fraction of Acont | |||||||||
| C area (%) | 55 | 56 | 53 | 53 | 41 | 45 | 46 | 50 | 48 |
| O area (%) | 25 | 24 | 31 | 32 | 33 | 35 | 37 | 32 | 38 |
| N area (%) | 21 | 20 | 16 | 15 | 27 | 20 | 18 | 16 | 14 |
| S area (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 |
| C aromatic (%) | 31 | 36 | 35 | 35 | 25 | 32 | 14 | 29 | 30 |
| C aliphatic (%) | 23 | 20 | 18 | 18 | 16 | 13 | 32 | 21 | 18 |
| Pos charged Area (%) | 5 | 3 | 3 | 3 | 5 | 0 | 16 | 16 | 2 |
| Neg charged Area (%) | 7 | 6 | 13 | 13 | 4 | 5 | 9 | 4 | 9 |
aSASA = Solvent accessible surface area.
b Acont = contact area between reference molecule and a symmetry related molecule.
c In house structure of human insulin co-crystallized with protamine.