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User:Tilman Schirmer/Sandbox 110
From Proteopedia
Repetitive torsion angles
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A polypeptide chain with a repetition of identical phi-psi torsion angles yields a helical structure.
phi-psi = (180o, 180o), fully extended chain:
,
.
Note the unfavorably between the carbonyl oxygen and the Cβ-atom of the next residue.
phi-psi = (-110o, 130o), extended chain:
,
,
; this is the β-strand conformation found in beta-sheets
Note:
Also strands with a are allowed, but they occur less frequent. This strand has phi-psi values of (-140o, 130o). See also Ramachandran Plots, http://en.wikipedia.org/wiki/Ramachandran_plot.
phi-psi = (70o, 180o):
,
; note that there are clashes (where?)
phi-psi = (-60o, -40o), α-helix:
,
phi-psi = (-50o, -26o), 310 helix: ,
