Give the amino acid sequence of hexapeptides that produce...

Give the amino acid sequence of hexapeptides that produce the following sets of fragments on partial acid hydrolysis: (a) Arg. Gly, lle, Leu, Pro, Val gives Pro-Leu-Gly, Arg-Pro, Gly-lle-Val (b) $\mathrm{N}, \mathrm{L}, \mathrm{M}, \mathrm{W}, \mathrm{V}_{2} \mathrm{g}$ ives $\mathrm{V}-\mathrm{L}, \mathrm{V}-\mathrm{M}-\mathrm{W}, \mathrm{W}-\mathrm{N}-\mathrm{V}$

Give the amino acid sequence of hexapeptides that produce the following sets of fragments on partial acid hydrolysis:
(a) Arg. Gly, lle, Leu, Pro, Val gives Pro-Leu-Gly, Arg-Pro, Gly-lle-Val
(b) $\mathrm{N}, \mathrm{L}, \mathrm{M}, \mathrm{W}, \mathrm{V}_{2} \mathrm{g}$ ives $\mathrm{V}-\mathrm{L}, \mathrm{V}-\mathrm{M}-\mathrm{W}, \mathrm{W}-\mathrm{N}-\mathrm{V}$

Key Concepts

Partial Acid Hydrolysis

Partial acid hydrolysis is a method used to cleave peptide bonds selectively, breaking down proteins or peptides into smaller, overlapping fragments. This controlled process does not fully hydrolyze the peptide, which allows researchers to obtain a series of fragments that share regions of the original sequence, providing clues to the order of amino acids in the peptide.

Peptide Fragmentation

Peptide fragmentation refers to the process by which proteins or peptides are broken down into smaller pieces through chemical or enzymatic means. In the context of partial acid hydrolysis, the generated fragments are of varying lengths and overlap with each other, which is crucial for reconstructing the complete amino acid sequence of the original peptide.

Overlapping Fragment Analysis

Overlapping fragment analysis involves comparing the sequence information of peptide fragments that share common sequences. By identifying the regions of overlap among the fragments, it is possible to determine the order and connection of amino acids in the original peptide sequence. This method is fundamental in deducing the primary structure of a peptide from its partial hydrolysis products.

Amino Acid Sequence Deduction

Amino acid sequence deduction is the analytical process of determining the linear order of amino acids in a peptide or protein. This process relies on the information derived from peptide fragments, especially overlapping sequences, to piece together the entire sequence of the molecule accurately. It is a key aspect of protein sequencing and understanding protein structure and function.

Transcript

00:01 Okay, so we are asked about partial acid hydrolysis of two peptides, starting with a.

00:07 Upon acid hydrolysis, we're left with a couple of residues.

00:10 The first is just this pro -lu -gly.

00:16 The second is orange pro, and the third is gly -i -l -e -val.

00:28 Okay, so it's worth noting that in this example, it tells us that there's only one type of each of these amino acid residues.

00:37 Right.

00:37 So it's not possible to have any sort of repeat or anything like that.

00:41 So the way i like to do these is basically just the biggest one i'm going to put in the middle, right? so i'm going to start just by putting proluigl.

00:52 Right in the middle like this.

00:55 All right.

00:55 So now i know based on this residue that there's got to be some sort of an arge before the pro.

01:01 Right? so i can do that.

01:02 I can write my arginine right here.

01:04 And that covers the first two residues.

01:08 The second one, i know that there's an isosine and a valine following a glycine.

01:13 Since i only have one glycine right here, that means the next two residues have to be isolucine, and then valine.

01:23 And that's the first one.

01:26 All right, so for part b, this time it gives us a couple of different residues.

01:32 The first being just using the one letter codes, vl.

01:37 The second one being vmw, and the third being wnv.

01:46 Okay...

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