| Allowed Value | Details |
|---|---|
| A-B | A to B transition steps (first nucleotide A, second B) |
| AAA | steps in the A form |
| AAu | A forms with bases partially unstacked |
| AAw | steps in the A form but some torsions (typically and ) have values switched from the typical values |
| B-A | B to A transition steps (first nucleotide B, second A) |
| B12 | Steps with torsion values bridging B and BII forms |
| BB2 | Steps in the BII ("b-two") form |
| BBB | Steps in the B form |
| BBw | Steps in the B form but some torsions (typically and ) have values switched from the typical values |
| ICL | Steps with parallel but distant bases that can be intercalated |
| NAN | Unassigned steps |
| OPN | Steps with unstacked, frequently distant bases and untypical torsion values |
| SYN | Steps containing base in the syn orientation |
| ZZZ | steps in the Z form |
| miB | Steps with B like sugar puckers and stacked bases but untypical torsion values |
| Allowed Value | Details |
|---|---|
| A-B | A to B transition steps (first nucleotide A, second B) |
| AAA | steps in the A form |
| AAu | A forms with bases partially unstacked |
| AAw | steps in the A form but some torsions (typically and ) have values switched from the typical values |
| B-A | B to A transition steps (first nucleotide B, second A) |
| B12 | Steps with torsion values bridging B and BII forms |
| BB2 | Steps in the BII ("b-two") form |
| BBB | Steps in the B form |
| BBw | Steps in the B form but some torsions (typically and ) have values switched from the typical values |
| ICL | Steps with parallel but distant bases that can be intercalated |
| NAN | Unassigned steps |
| OPN | Steps with unstacked, frequently distant bases and untypical torsion values |
| SYN | Steps containing base in the syn orientation |
| ZZZ | steps in the Z form |
| miB | Steps with B like sugar puckers and stacked bases but untypical torsion values |