A polypeptide with 80 amino acid residues is in a single contiguous alpha-helix. What is the approximate length of this helix?

Correct answer: 120 Angstroms

Explanation

The length of an alpha-helix can be calculated by multiplying the number of amino acid residues by the rise per residue. For an idealized alpha-helix, the rise per residue is 1.5 Angstroms.

Other questions

Question 1

What is the primary driving force for the folding of most soluble, globular proteins?

Question 2

According to the convention for dihedral angles in a peptide backbone, what values are assigned to phi and psi when the polypeptide is in its fully extended conformation?

Question 3

What are the characteristic number of residues per turn and the rise along the helical axis for an idealized alpha-helix?

Question 4

Which amino acid residue introduces a destabilizing kink in an alpha-helix and is thus only rarely found within one?

Question 5

In the Anfinsen experiment, what was the significance of the observation that denatured and reduced ribonuclease A could spontaneously refold into its native, catalytically active form?

Question 6

What is the structural basis for the strength of silk fibroin?

Question 8

What is the term for a recognizable folding pattern involving two or more elements of secondary structure and their connection, such as a beta-alpha-beta loop?

Question 9

What is the primary characteristic of intrinsically disordered proteins?

Question 10

Which protein is composed of a triple helix of polypeptide chains, with a repeating Gly-X-Y sequence?

Question 11

In a Ramachandran plot, what do the shaded regions represent?

Question 12

What is the term for a disease, such as Alzheimer disease, that is associated with the conversion of a normally soluble protein into an insoluble extracellular amyloid fiber?

Question 13

In the structure of myoglobin, where are the majority of the hydrophobic R groups located?

Question 14

Which technique is used to assess the secondary structure of proteins by measuring the difference in absorption of left-handed versus right-handed circularly polarized light?

Question 15

What is the typical rise per residue along the central axis of an idealized alpha-helix?

Question 16

What distinguishes parallel from antiparallel beta-sheets?

Question 17

The protein that makes up hair and wool, alpha-keratin, is an example of which type of protein?

Question 18

Levinthal's paradox addresses the problem of:

Question 19

Which of the following describes the quaternary structure of a protein?

Question 20

What type of enzyme catalyzes the interchange of disulfide bonds to facilitate correct protein folding?