Question

Some regions of protein secondary structure are described as "random coil". This designation is misleading because:

A. the secondary structure must always be an alpha helix or beta sheet.

B. although the structure is indeed random, it need not necessarily resemble a "coil".

C. although the region may be unique to a particular protein, it is not random: each cellular copy of that protein will contain an identical "random coil" structure that corresponds to the same portion of primary sequence.

D. an alpha helix represents one type of "coil", but its structure is certainly not random.

E. actually all types of secondary structure are random in nature.

Answer 1

Answer:

The answer for the above statement is (A) i.e., the secondary structure must always be an alpha helix or beta sheet.

Explanation:

Random coil : A protein that completely lacks secondary structure is random coil.

In random coil, the only fixed relationships between amino acids is that between adjacent residues through the peptide bond.

as a result random coils can be detected from the absence of signals in multi dimensional nuclear magnetic resonance experiment that depend on particular peptide-peptide interaction. Random coil is easily distinguished by circular dichroism.

Denaturing reduces a protein entirely to a random coil.