Why do alpha and beta tubulin monomers differ in sequence by 60%?

Which of the following statements are False? (i)     Parallel b-sheets characteristically distribute hydrophobic side chains on both sides of the sheet, and antiparallel B-sheets are usually arranged with all their hydrophobic residues on one side of the sheet. (ii)   Planarity of the peptide bond means that no rotation occurs about the N-Ca bond while rotation is allowed about the C(O)-N and Ca-C(O) bonds. (iii) Silk fibers consist of fibroin proteins consisting of alternating A and G or S residues. (iv) If an aspartic acid residue were present in the interior of a globular protein, it would most likely be deprotonated and thus negatively charged.

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

What is an oligopeptide? How is it different from a polypeptide?

Consider a short peptide with the sequence M-C-Q-L-Y-P-E-D-K. List the ionizable groups in this peptide, and the net charge of the whole peptide at pH a) 1.5, b) 7.0, and c)12.0.

Peptide 1: QAMGRAGDLKYLGLHSV Peptide 2: ALMALFMVMALVLVSVLFIA Peptide 3: MVEDLLKQIARYLISE Which of these peptides would be most likely to be found as an a helix in a soluble (cytoplasmic) protein? Which would be most likely to be found as an a helix in a transmembrane protein? Which would be least likely to form an a helix of any kind? Briefly explain your answers.

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.

Proteins function in a variety of roles in the body. The 3 main categories are: Growth and Maintenance, Regulatory Roles, and Energy Production.   Please provide 2 examples of Growth and Maintenance and 4 examples of Regulatory Roles