Table 2. A set of 18 beta-turn types derived from clustering of the RefinedSet of beta turns.
| No. by size | Size | Perc. | New name | Previous name | Median Cα1-Cα4 distance |
Residue 2 modal value |
Residue 3 modal value |
||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| ω | φ | ψ | ω | φ | ψ | ||||||
| 1 | 6,413 | 49.22 | AD | I | 5.48 | trans | -62 | -23 | trans | -96 | -2 |
| 2 | 1,556 | 11.94 | Pd | II | 5.61 | trans | -55 | 133 | trans | 91 | -6 |
| 3 | 802 | 6.16 | Pa | new (prev. II) | 6.00 | trans | -60 | 135 | trans | 59 | 28 |
| 4 | 748 | 5.74 | ad | I' | 5.44 | trans | 47 | 45 | trans | 83 | 1 |
| 5 | 648 | 4.97 | AB1 | new (prev. VIII) | 6.72 | trans | -67 | -31 | trans | -136 | 162 |
| 6 | 625 | 4.80 | AZ | new (prev. VIII) | 5.80 | trans | -74 | -28 | trans | -140 | 75 |
| 7 | 603 | 4.63 | AB2 | VIII | 6.42 | trans | -69 | -30 | trans | -120 | 128 |
| 8 | 402 | 3.09 | pD | II' | 5.44 | trans | 57 | -130 | trans | -95 | 11 |
| 9 | 166 | 1.27 | AG | new (prev. VIII) | 6.37 | trans | -66 | -19 | trans | -82 | 63 |
| 10 | 135 | 1.04 | BcisP | VIb | 5.70 | trans | -138 | 119 | cis | -66 | 164 |
| 11 | 131 | 1.01 | dD | new | 6.63 | trans | 94 | -1 | trans | -128 | 15 |
| 12 | 125 | 0.96 | PcisD | VIa1 | 5.74 | trans | -60 | 144 | cis | -93 | 8 |
| 13 | 102 | 0.78 | dN | new | 6.42 | trans | 69 | 9 | trans | -132 | -63 |
| 14 | 87 | 0.67 | Dd | new | 6.81 | trans | -115 | 16 | trans | 101 | -12 |
| 15 | 59 | 0.45 | PcisP | new (prev VIb) | 6.33 | trans | -66 | 148 | cis | -76 | 142 |
| 16 | 52 | 0.40 | cisDA | new | 5.36 | cis | -94 | 8 | trans | -61 | -38 |
| 17 | 32 | 0.25 | pG | new | 6.58 | trans | 74 | -162 | trans | -79 | 77 |
| 18 | 25 | 0.19 | cisDP | new | 6.36 | cis | -86 | 4 | trans | -71 | 158 |
| other | 319 | 2.45 | Other | IV | 6.42 | ||||||
| Total | 13,030 | 100.00 | |||||||||
The new nomenclature (column 4) based on the Ramachandran map positions (Fig 5) of residues 2 and 3 is provided next to the classical nomenclature. “cis” precedes conformations that contain cis peptide bonds for ω2 or ω3. “New” turns are those not similar to any types in the classical nomenclature. Some new turns are subclusters of the previous turn types; the one closest to the classical turn type is labeled with that type; the others are labeled “new” with the previous parent turn type given. The modal values of the dihedrals φ and ψ and the cis/trans configuration of residues 2 and 3 are shown. Complete information for 18 beta turns is provided in S1 Table and S1 Text. The BetaTurnLib18 files and beta-turn assignment Python tool, BetaTurnTool18 are at http://dunbrack.fccc.edu/betaturn or https://github.com/sh-maxim/BetaTurn18.