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16 Cards in this Set
- Front
- Back
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Why is there no rotation about the C-N bond?
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C-N bond has double bond character due to resonance from the C=O
This results in cis/trans conformations of enzymes More trans than cis |
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phi, φ
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Rotation at N-Ca
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psi, ψ
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Rotation at Ca-C
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What other factor restricts rotation of amino acids?
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Steric interference/Bond making between main and side chain atoms
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Amphipathic alpha helix
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Hydrophobic amino acid residues inward
Hydrophilic amino acid residues outward Stabilized by H bonds |
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Beta strands
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Polypeptide chain fully extended
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Beta sheets
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Multiple β strands side by side
Stabilized by H bonds between C=O and N-H Hydrophobic side chains would usually point to protein interior |
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Parallel Beta Sheets
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N-C same direction
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Antiparallel Beta Sheets
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N-C in opposite direction
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Loops and Turns
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Connected alpha helices and beta sheets
Loops are on protein surfaces and have hydrophilic residues Turns are 5 residues or less |
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Coiled coil
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two amphipathic helices interacting in parallel through hydrophobic edges
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Helix Bundle
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Several alpha helices in antiparallel bundle
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Beta alpha Beta
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Two beta parallel strands joined by alpha helix
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Beta Meander
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antiparallel sheet connected by loops and turns
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Greek Key
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4 antiparallel strands
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Beta Sandwich
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stacked beta strands or sheets
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