Skip to main content
Back

Alpha Helix Pitch and Rise definitions

Control buttons has been changed to "navigation" mode.
1/14
  • Alpha Helix
    A spiral-shaped protein secondary structure with a coiled backbone forming a helical conformation along a central axis.
  • Pitch
    The linear distance along the helix axis corresponding to one complete 360-degree turn of the backbone, measured as 5.4 Angstroms.
  • Rise
    The distance covered along the helix axis per amino acid residue, calculated as 1.5 Angstroms.
  • Angstrom
    A unit of length equal to 10⁻¹⁰ meters, commonly used to measure atomic-scale distances in molecular structures.
  • Backbone
    The continuous chain of atoms in a protein, excluding side chains, that forms the structural framework of the alpha helix.
  • Axis
    The central imaginary line running through the length of the alpha helix, around which the backbone coils.
  • Amino Acid Residue
    A single building block within a protein, contributing to the helix structure and rotation per turn.
  • Rotation
    The angular movement of the backbone per residue or per turn, with 360 degrees per turn and 100 degrees per residue.
  • Length
    The total distance spanned by the alpha helix, determined by multiplying the number of residues by the rise.
  • Conformation
    The specific three-dimensional arrangement of the protein backbone, such as the spiral shape of the alpha helix.
  • R Group
    The variable side chain attached to each amino acid, excluded from backbone calculations in helix measurements.
  • 360 Degrees
    The complete angular rotation of the backbone per turn in the alpha helix structure.
  • 100 Degrees
    The angular rotation of the backbone per amino acid residue within the alpha helix.
  • Formula
    The mathematical expression used to calculate helix length: number of residues multiplied by rise.