D raw the full structure of the following tetrapeptide . Label the N terminal and C terminal residues. Phe - Cys -  Ser - Ile

identify both L-amino acids

How does dithiothreitol (DTT) differ from B-mercaptoethanol (BME) as a reducing agent?

0ミレーNレ NH geometry on both cand N. Torigonal plannes CH - C-N o=), HN CH2 CH-C-OH (a- carbon) CH2 HooC Aspaxagine - Toline - Valine - Arginine - phenylalcmine - Glutamic ocid. 1.Give the name and three letter code for each amino acid in the peptide. e 2. At pH 7, approximately what charge would be on your peptide? Explain your answer. 3. Can your peptide form intra/interchain disulfide bonds? Explain why/why not. e 4. Will your peptide absorb UV and is it fluorescent? Explain why/why not. e 5. What is the probability that your peptide contains a cis peptide bond? Explain your answer.

A tetradecapeptide (14 amino acid residues) gives the following peptide fragments on partial hydrolysis. From this information, deduce the primary structure of this polypep- tide. Fragments are grouped according to size. Pentapeptide Fragments Tetrapeptide Fragments Phe-Val-Asn-Gln-His Gln-His-Leu-Cys His-Leu-Cys-Gly-Ser His-Leu-Val-Glu Gly-Ser-His-Leu-Val Leu-Val-Glu-Ala

1.  Amino acid analysis of the peptide gave the following residues: Asp Leu Lys Met Phe Tyr. The following facts were observed: Trypsin treatment had no effect. The phenylthiohydantoin released by Edman degradation was  C-C-CH2. Brief chymotrypsin treatment yielded several products including a dipeptide and a tetrapeptide. The tetrapeptide contained Leu, Lys and Met is some order. Cyanogen bromide treatment afforded a dipeptide, a tetrapeptide and a free Lys. What is the amino acid sequence for this heptapeptide?

Consider the peptide in the image and answer the following questions.

Identify and encircle the peptide bonds in this polypeptide (Asp-Sec-Leu-Cys-Glu).

Hydrophobic intercation associated with protein tertiary structure involve

D. Draw the structure of Histidine and Imidazole. Why do you think we use Imidazole to elute the protein? Why do we use a 6X His tag?