Tropomyosin, a 70-kDa muscle protein, is a two-stranded a-helical coiled coil. Estimate the length of the molecule.

The structure of an alpha helix orients the oxygens of the carbonyl group of the peptide bond towards the C-terminal end of the helix while the hydrogens of the NH groups orient toward the N-terminal end, thus imparting a dipole along the length of the helix.  As a result, which kinds of amino acids would favor the C-terminal end, and which would favor the N-terminal end? negatively charged, positively charged positively charged, negatively charged negatively charged, hydrophobic positively charged, hydrophobic hydrophobic, negatively charged hydrophobic, positively charged

Consider the hydrogen bonding pattern of an α-helix with the following sequence: HLRTNAGCSY Asparagine’s amide hydrogen is hydrogen bonded to:       a. Serine’s side chain   b. Histidine’s backbone carbonyl oxygen   c. Cysteine’s backbone carbonyl oxygen   d. Serine’s backbone carbonyl oxygen   e. Histidine’s side chain

Draw the molecular formula of the covalently modifi ed histone side chain of acetyllysine. How does this modifi cation alter the chemical properties of the side chain?