1.
The single-letter representation of the peptide sequence is as follows: T N C H P. The peptide diagram that satisfies the requirements that have been laid out is as follows:
2. The peptide contains the amino acids threonine (Thr, T), asparagine (Asn, N), cysteine (Cys, C), and histidine (His, H), as well as the amino acid proline (Pro, P).
3. The peptide, which has one amino acid that is basic (histidine) and one amino acid that is acidic (glutamic acid), would have a pH of 7 and be mildly basic (Asparagine). As a result, it would possess a trace amount of positive charge.
4. No, the peptide is not capable of forming intra- or interchain disulfide bonds since it does not contain any cysteine residues, which are necessary for the formation of such bonds.
5. The peptide will have a low level of ultraviolet (UV) absorption since it contains one aromatic amino acid (histidine), but it will not be fluorescent because it does not have any residues containing the amino acids trp, tyr, or phe.
6. Since all of the other peptide bonds are known to be in the trans configuration, the likelihood that the peptide in question has a cis peptide bond is extremely remote.
Explanation:
The peptide contains the amino acids threonine (Thr, T), asparagine (Asn, N), cysteine (Cys, C), and histidine (His, H). Moreover, the peptide contains proline (Pro, P). The peptide diagram that satisfies the above conditions can be found further down in this article. In this diagram, each of the heavy atoms is labeled with the letter that corresponds to it (C, N, O, S, etc.), and the number of hydrogen atoms that are linked to it is also depicted. The representation may also include some or all double bonds or partial double bonds. At a pH of 7, all ionisable groups are depicted in the state in which they have the highest population. It has been indicated that the peptide link between the fourth residue and proline is the cis isomer, whilst all of the other peptide bonds have been demonstrated to be in the trans configuration. The tetrahedral and L-isomer forms of the alpha carbon are depicted for each and every residue. Each and every trigonal planar group is displayed in full, along with the necessary geometry.
Due to the presence of both histidine, an amino acid with a positive charge, and glycine, an amino acid with an acidic charge, the peptide would have a pH of 7. (Asparagine). Histidine, a fundamental amino acid, has a pKa of 6.0 and is able to readily donate a proton, turning it into a positively charged species at a pH of 7. Asparagine, on the other hand, has a pKa of 4.5 and tends to remain neutral at a pH of 7. Despite this, it is still capable of very slightly donating a proton, which causes it to become very little positively charged. As a result, the peptide as a whole has an overall charge that is somewhat positive.
It is not possible for the peptide to create intra- or interchain disulfide bonds since it does not have any cysteine residues, which are necessary for the formation of such bonds. Cysteine residues have a sulfhydryl group (SH) that has the potential to generate disulfide bonds with other sulfhydryl groups in order to create intrachain or interchain disulfide bonds. Because of this, it is not possible for the peptide to establish bonds of this kind because it does not contain any cysteine residues.
Due to the presence of one aromatic amino acid, the peptide will have a low capacity for UV absorption (Histidine). Due to the presence of delocalized electrons, aromatic amino acids have a side chain that contains a structure that resembles an aromatic ring. This structure has the ability to absorb UV radiation. Yet, it will not emit any fluorescent light because it does not have any Trp, Tyr, or Phe residues in its structure. The presence of an indole or phenylalanine ring in the side chains of these residues confers upon them the ability to both absorb ultraviolet light and emit visible light, so conferring upon them the property of being fluorescent.
As all of the other peptide bonds are known to be in the trans configuration, the likelihood that the peptide in question has a cis peptide bond is extremely remote. Because they have a higher entropy and require less energy to form, trans peptide bonds are inherently more stable than their cis counterparts. Due to the fact that every other peptide bond is defined as being trans, the likelihood of the formation of a cis peptide bond is extremely remote.
In conclusion, the sequence of the peptide can be represented using a single letter code as T N C H P, and it is made up of the amino acids threonine, asparagine, cysteine, histidine, and proline. Due to the presence of both histidine, an amino acid with a positive charge, and glycine, an amino acid with an acidic charge, the peptide would have a pH of 7. (Asparagine). It is not possible for the peptide to create intra- or interchain disulfide bonds since it does not have any cysteine residues, which are necessary for the formation of such bonds. The peptide will have a low level of UV absorption due to the presence of one aromatic amino acid (histidine), but it will not be fluorescent due to the absence of any residues containing the amino acids tyrosine, tryptophan, or phenylalanine. As all of the other peptide bonds are known to be in the trans configuration, the likelihood that the peptide in question has a cis peptide bond is extremely remote. |
