AMINO ACIDS & PROTEINS
Enzymes (like other proteins) are polymers made from the 20 amino acids. An amino acid is a molecule with an amino group and a carboxylic acid group. The amino group of one reacts with the carboxylic acid of another as they become linked forming a protein. Each of the 20 has its own "personality" determined by its sidechain. A few examples:
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glycine the smallest allows the most freedom of rotation |
electrostatic
surface |
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asparagine polar |
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electrostatic
surface |
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phenylalanine nonpolar aromatic large |
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electrostatic
surface |
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aspartate negatively charged |
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electrostatic
surface |
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lysine positively charged |
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electrostatic
surface |
There are two major ways that the protein polymer will fold in on itself, as a helix or as a sheet.
You may find this tutorial using Protein G which has both structures useful. Much of the protein shape is determined by hydrophobic structures burying themselves in the middle of the protein.
You shouldn't think of the proteins as static structures but rather as waving and jiggling (sort of like the dancing baby)
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hydrophobic pocket |