User:Tilman Schirmer/Sandbox 100

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Contents

Secondary structure of proteins

outline:

Repetitive torsion angles

α-Helix

parallel β-sheet

antiparallel β-sheet





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: ,


phi-psi = (-140o, 130o), extended chain: , ; this is the β-strand conformation found in beta-sheets

Note:

polypeptide forms a with side-chains protruding towards alternating (up, down) directions

the polypeptide main-chain is as can been seen when looking along the chain

the point towards alternate directions


phi-psi = (70o, 180o): , ; note that there are clashes (where?)


phi-psi = (-60o, -40o), α-helix: ,


phi-psi = (-50o, -26o), 310 helix: ,


α-Helix

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An α-Helix is stabilized by main-chain between Oi and Ni+4. With .























parallel β-sheet

PDB ID 1tmy.pdb

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With .

























antiparallel β-sheet

PDB ID 1ema.pdb

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With .






















Anatomy of a protein

1tmy

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Response regulator receiver (Rec) domain. See also 1tmy.





The rest are the irregular .

























Notes

see also http://proteopedia.org/wiki/index.php/User:James_D_Watson/Structural_Templates

Proteopedia Page Contributors and Editors (what is this?)

Tilman Schirmer

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