6 PRINCIPLES OF PROTEIN FOLDING

conformation

a protein’s final folded structure

A protein may have multiple stable conformations T/F

T

what shape do proteins that function in aq env fold into and how does placement differ for hydrophillic/hydrophobic

sphere
- hydrophilic AA residue exposed to water placed on surface of protein

-hydrophobic AA residue nside protein, away from water

polypeptide folding in hydrophobic env

attach to biological membranes → hydrophobic surfaces embed inside hydrophobic core of phospholipid bilayer

3 non covalent interactions that support protein folding

1. van der waals

2. HBs

3. electrostatic interactions

unique protein foldign and name of bond

cysteine side chains form covalent disulfide bonds to connect to polypeptide backbone.

polypeptide backbone property

FLEXIBLE

what bonds in polypeptide backbone are flexible

C-N and C-C

why is proline inflexible

side chains loop back and covalently bonds to its own backbone N atom

4 ways to represent protein structure

a. peptide backbone as lines

b. peptide backbone as ribbons (shows secondary structures)

c. all atoms shown as sticks (shows side chains)

d. all atoms shown using space filling molecule (shows surface shape)

ways to analyze atomic structures of biological models

• x ray crystallography

• nuclear magnetic resonance

• cryo EM