Table 1.
Osmolyte* | SA+, Å2† | SA−, Å2† | SAo, Å2† | ΣSA, Å2‡ | Δgtr, cal/mol§ |
---|---|---|---|---|---|
TMAO | 0.0 | 43.2 | 168.4 | 211.6 | 89 ± 2 |
Betaine | 3.6 | 82.7 | 166.7 | 253.0 | 65 ± 3 |
Sucrose | 0.0 | 336.9 | 137.3 | 474.2 | 56 ± 6 |
Trehalose | 0.0 | 340.6 | 145.2 | 485.8 | 54 ± 8 |
Sarcosine | 24.5 | 43.3 | 141.6 | 209.4 | 50 ± 2 |
Sorbitol | 0.0 | 233.6 | 97.8 | 331.4 | 43 ± 7 |
Proline | 24.5 | 88.9 | 133.5 | 246.9 | 40 ± 8 |
Glycerol | 0.0 | 142.7 | 84.1 | 226.8 | 22 ± 8 |
Urea | 111.8 | 51.4 | 11.6 | 174.8 | −41 ± 2 |
Guanidine | 167.8 | 0.0 | 11.6 | 179.4 | −59 |
*The 10 osmolytes listed in Fig. 1.
†Osmolyte surface areas in Å2 with partial positive, negative, and neutral charge are indicated by SA+, SA−, and SAo, respectively.
‡Total surface area in Å2 = sum of SA+, SA−, and SAo.
§Δgtr is the free energy change that accompanies the transfer of a backbone unit from water to a 1 M osmolyte solution. Uncertainty in Δgtr values is based on two independent measurement techniques (11). Value for guanidine was provided by S. Sarker (personal communication).