Question

Please answer thoroughly, will rate thumbs up. thanks

Q1. Consider the following protein sequence:

Leu-Lys-Val-Asp-Ile-Ser-Leu-Arg-Leu-Lys-Ile-Arg-Phe-Glu.

1. What is special about the arrangement of the amino acids in these sequences when incorporated into a Beta sheet?
2. What prediction can you make about how this Beta sheet might be arranged in a cytoplasmic protein.

Q2. Consider the following protein sequence as an Alpha-helix:

Leu-Lys-Arg-Ile-Val-Asp-Ile-Leu-Ser-Arg-Leu-Phe-Lys-Val.

What is special about the arrangement of the amino acids in these sequences when folded into alpha helix?

Answer 1

Answer:-

1. The arrangement of amino acids in the above sequence made up of alternating charged non polar amino acids or polar amino acids. When this arrangement of amino acids would be incorporated in beta sheet, one face of the beta sheet would be hydrophobic and other would be non polar due to alignment of similar beta strands. Beta sheet might be arranged in a cytoplasmic protein in such a way that it's polar face resides outwards of the protein in order to interact with water molecules and its hydrophobic part remain inside of the protein.
2. The arrangement of the 14 amino acid residues in the above sequence would made 4 turns when folded into alpha helix. As we know, for the completion of one turn in alpha helix we need 3.6 amino acids residues. All the hydrophobic amino acids are arranged at one end and all the polar amino acids are arranged at the other side of sequence. When this arrangement of sequence folded into alpha helix which is susceptible to protein results its hydrophobic end to the inside of protein and polar end to the outside for further reaction.

Hope the above answer comes up to your expectation. Please do come up with your feedback.