Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Exercise 1 - determine the primary structure of the polypeptide One cycle of Edm

ID: 51478 • Letter: E

Question

Exercise 1 - determine the primary structure of the polypeptide

One cycle of Edman degradation yields PTH-Val

Trypsin digestion and sequencing yields the following peptide fragments

o T-N-V-K

o A-A-W-G-K

o V-L-S-P-A-K

o V-G-A-H-A-G-E-Y-G-A-E-A-T-E

Chymotrypsin digestion and sequencing yields the following peptide fragments

o G-A-E-A-T-E

o G-K-V-G-A-H-A-G-E-Y

o V-L-S-P-A-K-T-N-V-K-A-A-W

Exercise 2 - determine the primary structure of the polypeptide

Chymotrypsin digestion and sequencing yields the following peptide fragments

o R-I-P-K-C-R-K-F

o Q-Q-A-Q-H-L-R-A-C-Q-Q-W

o L-G-K-Q-A-N-Q-S-G-G-G-P-S

Trypsin digestion and sequencing yields the following peptide fragments

o K

o R

o C-R

o I-P-K

o A-C-Q-Q-W-L-G-K

o F-Q-Q-A-Q-H-L-R

o Q-A-N-Q-S-G-G-G-P-S

Exercise 3 - determine the primary structure of the protein

Treatment with cyanogen bromide and sequencing yields the following peptide fragments

o D-M

o L-F-M

o R-A-Y-G-N

Chymotrypsin digestion and sequencing yields the following peptide fragments

o G-N

o D-M-L-F

o M-R-A-Y

Explanation / Answer

Exercise 1:

Fragments obtained from Trypsin digestion are as follows:

o T-N-V-K

o A-A-W-G-K

o V-L-S-P-A-K

o V-G-A-H-A-G-E-Y-G-A-E-A-T-E

Fragments obtained from Chymotrypsin digestion are as follows:

o G-A-E-A-T-E

o G-K-V-G-A-H-A-G-E-Y

o V-L-S-P-A-K-T-N-V-K-A-A-W

These two sets of fragments are from the same polypeptide. Therefore, the sequence of the polypeptide can be known from these two sets of fragments.

The Primary structure or the sequence of amino acids of the polypeptide is as follows:

" V-L-S-P-A-K-T-N-V-K-A-A-W-G-K-V-G-A-H-A-G-E-Y-G-A-E-A-T-E "