Which of the following is not correct about the α-Helices?(a) An α-helix has a main chain backbone conformation that resembles a corkscrew(b) Nearly all known α-helices are right handed, exhibiting a leftward spiral form(c) Nearly all known α-helices are right handed, exhibiting a rightward spiral form(d) In right handed helix, there are 3.6 amino acids per helical turn

Which of the following is not correct about the α-Helices?(a) An α-h

1.	Which of the following is not correct about the α-Helices?(a) An α-helix has a main chain backbone conformation that resembles a corkscrew(b) Nearly all known α-helices are right handed, exhibiting a leftward spiral form(c) Nearly all known α-helices are right handed, exhibiting a rightward spiral form(d) In right handed helix, there are 3.6 amino acids per helical turn
Answer» Correct choice is (b) Nearly all known α-helices are right handed, exhibiting a leftward spiral form Easiest explanation: The structure is stabilized by hydrogen bonds formed between the main chain atoms of residues i and i + 4. The hydrogen bonds are nearly parallel with the helical axis. The average φ and ψ angles are 60◦ and 45◦, respectively, and are distributed in a narrowly defined region in the lower left region of a Ramachandran plot.

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