Protein Chemistry. Structure, Properties, Research Methods - Shendryk A.N. 2022

Protein Structure
Spatial Structure of Proteins

Currently, four levels of Structural Organization of the protein molecule are generally accepted. These are the primary, secondary, tertiary, and quaternary structures.

The Primary Structure is determined by:

> The Nature of the Amino Acids making up the molecule;

> the relative amount of each amino acid;

> The sequence of amino acids in the peptide chain.

If prosthetic groups are present, they are also included in the Introduction/19.html">Primary structure of the protein.

The Secondary structure is the spatial orientation of the main peptide chain, disregarding differences in the composition and conformation of side chains within these chains. Elements of the secondary structure include the helix, pleated sheets, Reverse Turns of chains, etc.

The tertiary structure reflects the complete spatial orientation of the protein molecule, including the orientation of the prosthetic group. Elements of the tertiary structure include globules, ellipsoids, rod-like shapes, and others.

The quaternary structure accounts for the non-covalent aggregation of two or more peptide chains into a single supramolecular complex.

The first three levels are used to describe all Proteins, while the fourth is reserved only for proteins consisting of two or more peptide chains.



Last update: 06/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.