Describe the properties of the principal types of secondary structure, including the α helix, the β sheet, and the reverse turn

Can the tertiary structure of a protein depend on the type of cell system used for synthesis? Explain.

Draw beta sheet with backbone hydrogen bonds, is this structure on the interior or exterior of the protein and why?   Region 1: -Ser-Thr-Glu-His- Region 2: -Asp-Tyr-Lys-Asn

Within a naturally-occurring polypeptide, under neutral pH conditions (pH = 7.0), which of the following amino acids always has a negatively charged carboxyl group? the first amino acid in the primary structure histidine lysine arginine the last amino acid in the primary structure

Polyglycine, a simple polypeptide, can form a helix with φ = -80°, ψ = +150°. From the Ramachandran plot (as shown), describe this helix with respect to handedness.

What role does symmetry play in the formation of protein assemblies built from identical subunits? What is a protomer? Use this term to distinguish between symmetric and pseudosymmetric assemblies.

Describe the helix-turn-helix (HTF) motif?

What is it about alpha helices and beta sheets that would make the coils less flexible?

What general structural feature is shared by proteins that specifically form homodimers (but not homotrimers, homoteramers etc)? Only one answer is correct.     the surface consists of hydrophilic alpha-helix.   the surface is highly modified by post-translational modification.   the surface is permanently bound by chaperones.   the surface is unstructured.   the surface, or part of it, is self-complementary.

If a quaternary (4°) protein structure has six N-terminus. How many total subunits does it have?