Protein sequences are customarily 'reconstructed' from sequenced fragments because You have purified a new peptide hormone

1. Protein sequences are customarily 'reconstructed' from sequenced fragments because

large polypeptides cannot be directly sequenced

2. You have purified a new peptide hormone. To determine its amino acid sequence you have digested the polypeptide with trypsin and in a separate reaction you have cleaved the polypeptide with cyanogen bromide.
   Cleavage with trypsin yielded 5 peptides that were sequenced by Edman degradation as shown in the following.
   
   1. Ser-Leu
   2. Asp-Val-Arg
   3. Val-Met-Glu-Lys
   4. Ser-Gln-Met-His-Lys
   5. Ile-Phe-Met-Leu-Cys-Arg
   
   Cleavage with cyanogen bromide yielded 4 peptides that were sequenced by Edman degradation:
   
   1. His-Lys-Ser-Leu
   2. Asp-Val-Arg-Val-Met
   3. Glu-Lys-Ile-Phe-Met
   4. Leu-Cys-Arg-Ser-Gln-Met
   
   Determine the identity of the N-terminal amino acid after reconstructing the intact protein.

Asp

3. In two homologous proteins, which residue is most likely to replace a Glu residue as a conservative substitutio

Asp

4. A phylogenetic tree depicts ___________ of proteins.

evolutionary relationships

5. A protein that has had few changes in its amino acid sequence over evolutionary history is labeled

evolutionarily conserved

6. Paralogous genes are

the results of gene duplication

7. A fast way for nature to generate new proteins is:

shuffling protein domains or motifs

8. ___________ is an example of a very slowly evolving protein.

Histone H4

9. Proteins are often constructed from multiple segments of 40-200 amino acid residues, commonly called

domains

10. Why are degradative enzymes a concern during protein purification?

They can co-purify with the protein of interest