10 protein structure Flashcards
primary structure
peptide bond
what is a peptide bond?
alpha amino group is linked to alpha COOH of the next amino acid
how is a peptide bond formed?
condensation
a polypeptide chain ends with a free _____ group
COOH; the carboxy terminus
the carboxyl oxygen and amino hydrogen is always ______ to each other
trans
secondary structure
- hydrogen bonds
- alpha helix, B sheets, suprahelix
what causes an alpha helix to form?
- L form of amino achiral amino acids
- stabilization through hydrogen bonding
what sequence of polar/nonpolar amino acids favors the formation of an alpha helix?
PNPPNNP
what amino acids disrupt the formation of an alpha helix?
proline and hydroxyproline due to their lack of an NH2 group
what are the segments of a polypeptide chain in a B-pleated sheet called?
B strands
what sequence of polar/nonplar amino acids favors the formation of a B pleated sheet?
NPNPNP
what does a parallel sheet look like?
looks like the backbone zips nicely but the inside has diagonally formed hydrogen bonds between amine and COOH
what does antiparallel sheet look like?
backbone likes like it won’t zip but the inside has nice and straight formed hydrogen bonds between carbonyl carbon of COOH and amine
where are suprahelices found?
collagen
what does a suprahelix look like?
a rope braid
