Biology

Difference between Alpha Helix and Beta Pleated Sheet

Main Difference

The motif located at the secondary structure of proteins and becomes standard as a coiled like or spiral right-hand confirmation that gives it the distinction of a helix, hence commonly known as an alpha helix. On the other hand, the beta pleated sheet also called the b-sheet gets defined as the standard motif of the characteristic secondary structure present in the proteins.

Comparison Chart

Basis of Distinction Alpha Helix Beta Pleated Sheet
Definition The motif located at the secondary structure of proteins and becomes standard as a coiled like or spiral right-hand confirmation that gives it the distinction of a helix. The beta pleated sheet also called the b-sheet gets defined as the standard motif of the characteristic secondary structure present in the proteins.
Amino Acids The -R groups of amino acids exist on the outside surface. The -R groups exist on the outside and inside surface of the sheet.
Bonding The hydrogen bonds get created within the polypeptide chain for creating helical structures. Exist by linking of two or more than two beta strands from hydrogen bonds.

Alpha Helix

The motif located at the secondary structure of proteins and becomes standard as a coiled like or spiral right-hand confirmation that gives it the distinction of a helix, hence commonly known as an alpha helix. Here, within the structure, the N-H group denotes a hydrogen bond to the C=O group called the backbone of amino acids which becomes present in four residues before the protein sequence. Two key advancements in the demonstrating of the present day α-helix were: the right bond geometry, because of the precious stone structure judgments of amino acids and peptides and Pauling’s expectation of planar peptide bonds; and his giving up of the suspicion of a necessary number of deposits per turn of the helix. The vital minute came in the early spring of 1948 when Pauling came down with a bug and went to bed. Being exhausted, he drew a polypeptide chain of generally right measurements on a piece of paper and collapsed it into a helix, being mindful to keep up the planar peptide bonds. The alpha helix is the most well-known helix found in nature. It comprises of a wound polypeptide chain, in which the side chains of the amino acids broaden outward from the center, this enables it to keep up its shape. They can be found in a wide range of sorts of proteins, from globular proteins, for example, myoglobin to keratin, which is a stringy protein. It can either be a privilege gave or left-hand helice yet it has been demonstrated that the alpha helix loop is supported as the side chains don’t conflict. This info gives the alpha-helix steadiness. There are 3.6 amino corrosive deposits for each turn of the alpha-helix curl.

Beta Pleated Sheet

The beta pleated sheet also called the b-sheet gets defined as the standard motif of the characteristic secondary structure present in the proteins. The distinction it has over other proteins becomes the factor that it consists of strands that have a connection with at least two or three of the hydrogen atoms present within the structure that form the pleated sheet. A β-strand is an extent of polypeptide anchor regularly 3 to 10 amino acids long with the spine in a broadened adaptation. The supramolecular relationship of β-sheets has embroiled in the arrangement of the protein totals and fibrils seen in numerous human sicknesses, eminently the amyloidoses, for example, Alzheimer’s malady. This structure happens when two portions of a polypeptide chain cover each other and shape a line of hydrogen bonds with each other. This action can occur in a parallel course of action or in hostile to parallel plan. Parallel and against the same game plan is the immediate outcome of the directionality of the polypeptide chain. A corresponding structure to the beta-creased sheet is the α-creased sheet. This structure is enthusiastically less ideal than the beta-creased sheet and is genuinely unprecedented in proteins. A α-creased sheet gets described by the arrangement of its carbonyl and amino gatherings; the carbonyl groups are altogether adjusted in one heading, while all the N-H gatherings are adjusted the other way.

Key Differences

  • The motif located at the secondary structure of proteins and becomes standard as a coiled like or spiral right-hand confirmation that gives it the distinction of a helix, hence commonly known as an alpha helix. On the other hand, the beta pleated sheet also called the b-sheet gets defined as the standard motif of the characteristic secondary structure present in the proteins.
  • The -R groups of amino acids exist on the outside surface of the helix, whereas, the -R groups exist on the outside and inside surface of the sheet.
  • The alpha helix is a polypeptide chain that is pole molded and wound in a spring-like structure, held by hydrogen bonds. On the other hand, Beta pleated sheets get made of beta strands associated along the side by at least two hydrogen bonds shaping a spine.
  • A helix can be left hand (beta) or right-hand where the alpha helix is constantly right-hand. On the contrary, the chains are adjusted one next to the other to each other string arranged inverse of the other in beta pleated sheets.
  • The formation of alpha helix exists such that the hydrogen bonds get created within the polypeptide chain for creating helical structures. On the other hand, beta pleated sheets exist by linking of two or more than two beta strands from hydrogen bonds.

Video Explanation

Add Comment

Click here to post a comment

Your email address will not be published. Required fields are marked *