Table 3.
Average distances (SDs) of hydrogen-bonded atoms |
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---|---|---|---|---|---|
System | No. of family: hydrogen-bonded atom-pairs: occurrence probability (%) | First bond | Second bond | Third bond | Fourth bond |
FF | 1: HA-TB and N2A-TB and TA-N2B and TA-HB: 68% | 2.8 (0.1) | 2.9 (0.2) | 2.9 (0.2) | 2.8 (0.1) |
2: HA-TB and O1A-N2B: 19%∗ | 2.9 (0.3) | 3.2 (0.4) | — | — | |
3: HA-O1B and TA-HB: 14%∗¶ | 3.2 (0.4) | 2.9 (0.3) | — | — | |
4: only (HA-TB and TA-N2B): 6% | 2.9 (0.3) | 3.3 (0.4) | — | ||
5: HA-O1B and O1A-HB: 3%¶ | 3.4 (0.4) | 3.4 (0.4) | |||
FFF | 1: O1A-N3B and N3A-O1B§: 57% | 3.0 (0.3) | 3.0 (0.3) | — | — |
2: TA-HB and N3A-O2B: 14%† | 2.8 (0.2) | 3.1(0.3) | — | — | |
3: TA-HB and N3A-O1B: 12%† | 2.9 (0.2) | 3.2 (0.4) | — | — | |
4: N2A-O2B and O2A-HB: 6%‡ | 3.4 (0.4) | 3.1(0.4) | — | — | |
5: HA-O2B and O1A-N2B: 5% | 2.6 (1.0) | 2.6 (1.0) | — | — | |
6: N2A-2B and O2A-N2B: 4%‡ | 3.2 (0.4) | 3.2 (0.4) | — | — | |
other / 4% | - | — | |||
Notation | FF | FFF | |||
The analysis was performed for the two-stranded sheets listed in Table 2. The atom notation is explained in the last panel of the table; A and B refer to the two strands of the sheet.
∗,¶In FF, a subset of sheets satisfy simultaneously the criteria of families 2 and 3, or 3 and 5.
†,‡In FFF, a subset of sheets satisfy simultaneously the criteria of families 2 and 3, or 4 and 6.
§Eight percent of conformations have two additional head-tail interactions; 24% of conformations have one additional head-tail interaction.