Table II.
Winnowing the Reference Population Using H-Bond Satisfaction and H-Bond Energya
| Structural category | Reference | H-bond satisfaction | H-bond energy |
|---|---|---|---|
| H2S | 11 (99.3) | 12 (99.3) | 11 (99.3) |
| H3S | 44 (87.5) | 51 (95.3) | 38 (96.1) |
| H4S | 42 (24.8) | 43 (24.8) | 49 (93.9) |
| H2H | 12 (76.0) | 12 (76.0) | 14 (81.8) |
| H3H | 44 (63.3) | 45 (63.3) | 43 (93.8) |
| H4H | 46 (34.7) | 38 (32.8) | 42 (74.3) |
| S2H | 13 (94.5) | 12 (94.5) | 13 (94.5) |
| S3H | 38 (68.8) | 38 (63.7) | 34 (63.7) |
| S4H | 41 (39.2) | 44 (43.4) | 39 (74.5) |
| S2S | 7 (74.8) | 6 (74.8) | 3 (74.8) |
| S3S | 24 (41.4) | 25 (51.0) | 24 (51.0) |
| S4S | 34 (38.3) | 40 (40.5) | 20 (48.5) |
a
Number of unique turns in three sets: (col. 2) the reference set (col. 3) H-bond satisfaction applied to col. 2, and (col. 4) H-bond energy applied to col. 3. Numbers in parentheses are the % of the experimentally determined turns captured by this set. The number of unique turns in successive sets can decrease with additional H-bonding constraints when the populations of newly stabilized turns increase, forcing other previously populated turns below the 0.5% threshold. Note that these simulations are for a polyalanyl model.