The alpha helix and beta sheet are found at which level of protein organisation?
(or)
The α-helix and β-pleated sheet are examples of which level of protein ?
A. Primary structure
B. Secondary structure
C. Tertiary Structure
D. Quaternary structure
Answers: B (Secondary structure).
Explanation: After primary structure formation, the regions that are closely arranged will come together to form weak interactions by hydrogen bonding, which generate either α-helix or β-pleated sheets of secondary structure.
Interestingly, it is the only structural level in which covalent interactions are not present but hydrogen bonds can form the noncovalent interactions in local folding.
Basically, three types of regular right-handed helical structures have been studied such as α-helix, 310 helix, and π (pi) helix.
In the case of the beta-pleated sheets, two structural forms such as parallel and antiparallel forms have been noticed on the basis of the β-strand arrangements.
To read more about four levels of protein structure and examples, click here.
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