310 helix

Max Perutz, the head of the Medical Research Council Laboratory of Molecular Biology at the University of Cambridge, wrote the first paper documenting the elusive 310-helix.

[1] Together with Lawrence Bragg and John Kendrew, Perutz published an exploration of polypeptide chain configurations in 1950, based on cues from noncrystalline diffraction data as well as from small molecule crystal structures such as crystalline found in hair.

[5] Pauling was highly critical of the helical structures proposed by Bragg, Kendrew, and Perutz, taking a triumphal tone in declaring them all implausible.

[16] They are almost always short sections, with nearly 96% containing four or fewer amino acid residues,[17]: 44  appearing in places such as the "corners" where α-helices change direction in the myoglobin structure, for example.

[8] Longer sections, in the range of seven to eleven residues, have been observed in the voltage sensor segment of voltage-gated potassium channels in the transmembrane domain of certain helical proteins.

310-helices often arise in transitions, leading to typically short residue lengths that result in deviations in their main-chain torsion angle distributions and thus irregularities.

Their hydrogen bond networks are distorted when compared with α-helices, contributing to their instability, though the frequent appearance of the 310-helix in natural proteins demonstrate their importance in transitional structures.