page_title: Beta helix
hierarchical_section_title: Beta helix
caption_attribution_description: English: Right-handed beta helix antifreeze protein. Made with MOLMOL. Deutsch: Bändermodell eines Frostschutzproteins des Mehlkäfers (Tenebrio molitor) in zwei verschiedenen Ansichten. Eine Seitenfläche der β-Helix wird durch parallele Beta-Faltblattstrukturen gebildet.
context_page_description: A beta helix is a tandem protein repeat structure formed by the association of parallel beta strands in a helical pattern with either two or three faces. The beta helix is a type of solenoid protein domain. The structure is stabilized by inter-strand hydrogen bonds, protein-protein interactions, and sometimes bound metal ions. Both left- and right-handed beta helices have been identified. Double stranded beta-helices are also very common features of proteins and are generally synonymous with jelly roll folds.
  The first beta-helix was observed in the enzyme pectate lyase, which contains a seven-turn helix that reaches 34 Å long. The P22 phage tail spike protein, a component of the P22 bacteriophage, has 13 turns and in its assembled homotrimer is 200 Å in length. Its interior is close-packed with no central pore and contains both hydrophobic residues and charged residues neutralized by salt bridges.
  Both pectate lyase and P22 tailspike protein contain right-handed helices; left-handed versions have been observed in enzymes such as UDP-N-acetylglucosamine acyltransferase and archaeal carbonic anhydrase.
context_section_description: A beta helix is a tandem protein repeat structure formed by the association of parallel beta strands in a helical pattern with either two  or three  faces. The beta helix is a type of solenoid protein domain. The structure is stabilized by inter-strand hydrogen bonds, protein-protein interactions, and sometimes bound metal ions. Both left- and right-handed beta helices have been identified. Double stranded beta-helices are also very common features of proteins and are generally synonymous with jelly roll folds.
  The first beta-helix was observed in the enzyme pectate lyase, which contains a seven-turn helix that reaches 34 Å (3.4 nm) long. The P22 phage tail spike protein, a component of the P22 bacteriophage, has 13 turns and in its assembled homotrimer is 200 Å (20 nm) in length. Its interior is close-packed with no central pore and contains both hydrophobic residues and charged residues neutralized by salt bridges.
  Both pectate lyase and P22 tailspike protein contain right-handed helices; left-handed versions have been observed in enzymes such as UDP-N-acetylglucosamine acyltransferase and archaeal carbonic anhydrase. Other proteins that contain beta helices include the antifreeze proteins from the beetle Tenebrio molitor (right-handed) and from the spruce budworm, Choristoneura fumiferana (left-handed), where regularly spaced threonines on the β-helices bind to the surface of ice crystals and inhibit their growth.
  Beta helices can associate with each other effectively, either face-to-face (mating the faces of their triangular prisms) or end-to-end (forming hydrogen bonds).  Hence, β-helices can be used as "tags" to induce other proteins to associate, similar to coiled coil segments.
  Members of the pentapeptide repeat family have been shown to possess a quadrilateral beta-helix structure.
caption: Dimeric, right-handed β-helix antifreeze protein from the beetle Tenebrio molitor (PDB: 1EZG​). Face-to-face association of β-helices.
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