Biology And Biomedical Sciences BIOL 2960 Lecture Notes - Lecture 6: Alpha Helix, Amine, Carbonyl Group
1 Feb 2017
School
Department
Document Summary
Amino acids have stereo isomers due to chiral carbon. L and d l is most common. Ionization state of amino acids change as a function of ph increasing. Polar due to o in side chain, but no overall charge. Have a + charge in the side chain. Cysteine contains sh which can form disulfide bridges with other nearby cysteine residues. Glycine very small, can fit in tight corners. Proline side chain is bonded to amino group as well as alpha c. Sequence of amino acids linked by peptide bonds. Linear, free amino group at one end and free carboxyl at other. Peptide bonds are double bond like (exists in resonance) Peptide bonds are planar, not rotatable around the peptide linkage. Can be cis or trans, but almost always in trans due to space limitations in cis bonding. Folding of main chain due to h-bonding between the slightly positive amino group and slightly negative carboxyl groups in the peptide bond.
