| Allowed Value | Details |
|---|---|
| a-form double helix | |
| b-form double helix | |
| bulge loop | |
| double helix | |
| four-way junction | |
| hairpin loop | |
| internal loop | |
| mismatched base pair | |
| other right-handed double helix | |
| parallel strands | |
| quadruple helix | |
| tetraloop | |
| three-way junction | |
| triple helix | |
| two-way junction | |
| z-form double helix |
| Allowed Value | Details |
|---|---|
| a-form double helix | |
| b-form double helix | |
| bulge loop | |
| double helix | |
| four-way junction | |
| hairpin loop | |
| internal loop | |
| mismatched base pair | |
| other right-handed double helix | |
| parallel strands | |
| quadruple helix | |
| tetraloop | |
| three-way junction | |
| triple helix | |
| two-way junction | |
| z-form double helix |