BIOA01H3 Chapter Notes - Chapter 4-4.3: Alpha Helix, Protein Folding, Carboxylic Acid
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BIOA01H3 Full Course Notes
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Document Summary
Amino acids have diff. side chains have alpha carbon + carboxyl/amino terminals can become +ve or ve charged depending on environment. Aa are joined by peptide bonds carboxyl reacts w/amino (dehydration synthesis) polymer of aa are called polypeptides (proteins), residue are aa used to form protein. Aa sequence dictates folding and structure: primary structure linear sequence of aa (determine secondary structure, secondary structure interactions between aa nearby, create alpha helix or beta sheets. >> in alpha helix, each carboxyl group forms h-bonds w/amide group 4 residues away. >> in beta sheets (antiparallel), polypeptide folds back and forth on itself stabilized by h-bonds between amide and carboxyl groups in diff. chains: tertiary structure long range interactions between secondary structures that support 3-d shape. Come from interactions between r-groups spatial distribution of hydrophobic/phallic r-groups. Determines functions diff. structure = enzyme, membrane proteins, signal etc.
