1. The following is a polypeptide with the sequence given. Identify the amino ac

Question

1. The following is a polypeptide with the sequence given. Identify the amino acids region that would be most likely form a transmembrane alpha Helix in the sequence. It should be about a 19 to 20 amino acid long segment. Give the transmembrane region by the numbers of amino acids (such as 10 to 30 or something like that) and fully explain your reasoning for choosing that sequence.

(insert amino acid range here)
(type explanation here)

2. Membrane proteins are often glycosylated when they extend outside of the membrane bilayer but not on the side of a cytosolic side. What are the individual amino acids that could have carbohydrates attached to them and this transmembrane glycoprotein? Identify the amino acids by three letter abbreviation and number. For example, if you feel alanine number 44 could be carboxylated, list alanine - 44 as one of the options.

i. The following is a polypeptide with the sequence given. Identify the amino acids region that would be most likely form a transmembrane alpha helix in this sequence. This should be about a 19-20 amino acid long segment. Give the transmembrane region by the numbers of amino acids (such as 10-30 or something like that) and fully explain your reasoning for choosing that sequence. (3 pts). finsert the amino acid range here] I type explanation here] N-terminus Ala Arg Tyr Val Asn Gly Gln Ser Ala Trp le Met Leu Val Trp 10 Phe 21 Thr A 11 A 4 1A Gly 7 10 11 12 13 14 15 lle 16 Asn 31 Asn Leu lle Met le Leu Leu Gn Met Phe A 17 18 19 20 21 2223 24 25 26 7 28 29 30 Arg Ala Ser Asn Thr Gly Asp Val Asn Glu Leu Thr Ala Asn 32 33 34 35 36 37 38 39 40 41 42 43 44 45 le Thr Thr C terminus 47 48 49 eu 19 AS Ala Ille Asn Gly 2 ASP 39 33 Ser 20 le 41 Leu 28 nus 37 Asp 24 46 47 Thr34 fi. Membrane proteins are often glycosylated when they extend outside of the membrane bilayer but not on the cytosolic side. What are the individual amino acids that could have carbohydrates attached to them in this transmembrane glycoprotein? Identify the amino acids by three letter abbreviation and number. For example, if you feel alanine number 44 could be carboxylated, list Ala-44 as one of the options. (3 pts) Insert amino acid numbers and three letter abbreviations herej

Explanation / Answer

1 The sequence

-Gly30 - Asn 31 - Arg32- Ala33 - Ser34 - Asn35- Thr36 - Gly37- Asp38 - Val39- Asn40 - Glu41- Leu42 - Thr43 - Ala44- Asn45- Thr46 -Ile47 -Thr48-Thr49 .

reason : serine and threonine are very efficient in making the hydrogen bonds which aids the formation of alpha helixs. So the number of serine and threonine is high in this chain.Hence it is choosen. Also, aminoacid residues like glycine provide kinks to the helix which help in the biological function of the membrane protein.

2. Glycosylation usually happens Nitrogen and Oxygen. Therefore, the aminoacids with oxygen and nitrogen in the R groups are preferable to get glycosylated. (Arginine,Serine,lysine and threonine)

So, The amino acid that get glycosylated is Arg2 . Eventhough seine and threonine are present in the peptide chain, the possibility of them getting glycosylated very less because they are involved in the hydrogen bond formation and are responsible for the alpha helix structure.

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