# Riboswitch states: ligand occupancy of the aptamer and the regulatory output of the expression platform.
id: riboswitch
name: Riboswitches
applies_to: Riboswitches (Rfam riboswitch families), as aptamer plus expression platform.
source:
  - citation: "Serganov A, Nudler E (2013) A decade of riboswitches. Cell 152:17-24."
    doi: 10.1016/j.cell.2012.12.024
    url: null
axes:
  - id: aptamer
    name: Aptamer
    terms:
      - {id: aptamer_unbound, name: aptamer unbound, definition: "Aptamer without its ligand; may be partly folded or preorganised."}
      - {id: aptamer_bound, name: aptamer bound, definition: "Aptamer folded around its ligand."}
  - id: expression_platform
    name: Expression platform
    terms:
      - {id: platform_on, name: expression ON, definition: "Platform conformation that allows expression (antiterminator formed, or ribosome-binding site exposed)."}
      - {id: platform_off, name: expression OFF, definition: "Platform conformation that blocks expression (terminator formed, or ribosome-binding site sequestered)."}