Biochemistry: Ploypeptide sequence vDraw the sequence of the native polypeptide,
ID: 53029 • Letter: B
Question
Biochemistry: Ploypeptide sequence
vDraw the sequence of the native polypeptide, indicating which positions might not be determined by these data.
vA decapeptide has the following amino acid composition:
( Arg, Gly2, His3, Leu, Met, Phe2)
§Reacting the native peptide with FDNB and then hydrolyzing released 2,4-dinitrophenylglycine.
§Incubation with CNBr yielded two fragments, a tetrapeptide with composition (Gly2, Met, Phe) and a hexapeptide.
•The tetrapeptide yielded 2,4-dinitrophenylglycine
•The hexapeptide yielded 2,4-dinitrophenylleucine
§Proteolitic cleavage by trypsin of the native peptide gave two fragments, a hexapeptide and a tetrapeptide
•The tetrapeptide yielded 2,4-dinitrophenylphenylalanine
§Pepsin cleavage of the native peptide gave a dipeptide composed only of glycine and two tetrapeptides.
N _ _ _ _ _ _ _ _ _ _ C
Explanation / Answer
The sequence if the peptide is Gly-Gly-Met-Phe-Leu-Arg-Phe-His-His-His. This is in the order of N to C terminus. Each of the reagents used above have specific properties. Carefully reading the above data will reveal the sequence of the protein as mentioned above.
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