Biochem CH4

____ _______:

  Proteins will select a folding conformation that gives the lowest free energy. Dominated by hydrophobic effects, and stabilized via H-bonding, ionic boding, and covalent bonding.

The polarity of water causes the hydrophobic portions of the amino acid (nonpolar R groups) to be internalized and pushed together, whereas the polar (hydrophilic portions) will be located on the outside of the protein exposed to the water molecules. These interactions drive the formation of the ______ _____, in which the lowest free energy state is achieved (more spontaneous).

  Polar/Charged groups are usually ______ and usually on the surface of the protein.

Peptide Bond:

Rotation along the ____ bond is prohibited.

  Phi (Φ) is usually between ____° and -180°

Psi (Ψ) is usually between ____° and +190°

  For _____, phi is limited to -35° to -85°.

(specific amino acid)

  Sterically bulky residues destabilize the α helix, which is why _____ is considered a helix breaker.

Alpha helixes have a pitch of ___ Å, and 3.6 amino residues per turn.

In an alpha helix, high ____ content favors formation of an alternate secondary structure.