Nucleotides and Amino Acids

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Nucleotides and Amino Acids

• PR 613 Structural Biology I
• Dr. Eric Wickstrom

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Structure dictates function
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Nucleic Acids
Triple helix
Southern Northern
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Catalytic RNA
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Antiparallel B-form (Southern) double helix
Ring stacking and hydrophobic repulsion stabilize
helix. Hydrogen bonds permit close approach, but
dont add stability!
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Dynein TcTex1
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C to N, over the bridge
Sidechain on the left in an L-amino acid
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Aromatic (p-orbital) amino acids
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pK 10.5
pK 4 pK 4
pK 8
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pK 10.5 pK 12.5 pK 6
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Sperm whale myoglobin
a-helix 3.6 aa/turn 5.4 Å/turn 1.5 Å/aa
8 a-helices
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Prealbumin
b-sheet 2.0 aa/turn 7 Å/turn 3.5 Å/aa
16 b-sheets
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b-turns