Protein folding
Process by which a linear amino acid chain folds into functional 3D structure.
Last updated
Protein folding is the physical process where a linear amino acid chain from a ribosome becomes a stable three-dimensional structure.[1] A protein's biological activity depends on its three-dimensional structure.[1] The native structure and the route to achieve it are both encoded within a protein's amino acid sequence.[2]
Quick Facts
- Field
- Molecular biology
- biochemistry
- biophysics
- Known for
- Determination of native protein structure from amino acid sequence; role in disease from misfolding
- Key concept
- Primary structure determines tertiary structure
- Time scale
- Milliseconds to minutes or hours
- Driving forces
- Hydrophobic effect
- hydrogen bonds
- van der Waals forces
Facts from the source article.
Key facts and history
Formation of secondary structures like alpha helices and beta sheets is the first step in the folding process.[3] These structures fold rapidly because they are stabilized by intramolecular hydrogen bonds.[3] The hydrophobic effect, where nonpolar side chains collapse into the protein core, is a major driving force for folding.[4] Molecular chaperones are proteins that aid correct folding in cells by preventing incorrect conformations.[5]
Failure to fold correctly can produce inactive or toxic proteins.[6] Co-translational folding, where the polypeptide chain starts to adopt its structure while still being synthesized by the ribosome, is common for many proteins.[7] Interactions between amino acids generate a specific three-dimensional conformation, which is termed the native state.[7] The primary sequence of a protein dictates its final three-dimensional arrangement.[7]
What the research sources say
The torsion angles Phi and Psi are central to defining secondary structure elements and protein folding.[8] A section of a polypeptide chain illustrates the rotation around bonds that define these Phi and Psi angles.[8] Protein folding in the cell is a complex process assisted by chaperones and catalyzed by enzymes like protein disulfide isomerase.[9] Levinthal's paradox observes that proteins do not fold by trying every possible conformation, as that would take an astronomical time.[10]
For the major capsid protein gp23 of bacteriophage T4 to fold correctly in vivo, it requires the stable complex formed between the phage-encoded gp31 protein and the host's GroEL chaperonin.[9] Proteins in a normal cellular environment will, on their own, adopt their native folded state.[10]
References
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: Alberts, "Molecular Biology of the Cell; Fourth Edition", Garland Science, 2002 (original not read by us) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: Voet, "Principles of Biochemistry", Wiley, 2016 (we also read that source) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: "A backbone-based theory of protein folding", Proceedings of the National Academy of Sciences of the United States of America, November 2006, p. 16623–33; Voet, "Principles of Biochemistry", Wiley, 2016 (we also read that source) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: "Forces contributing to the conformational stability of proteins", FASEB Journal, January 1996, p. 75–83; Voet, "Principles of Biochemistry", Wiley, 2016; "Protein-spanning water networks and implications for prediction of protein–protein interactions mediated through hydrophobic effects", Proteins, December 2014, p. 3312–26 (we also read that source) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: "Protein folding and misfolding", Nature, December 2003, p. 884–90; "Molecular chaperones in cellular protein folding", Nature, June 1996, p. 571–9; "Molecular chaperones in cellular protein folding", Nature, June 1996, p. 571–9; "Protein folding and misfolding", Nature, December 2003, p. 884–90 (original not read by us) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: "Folding proteins in fatal ways", Nature, December 2003, p. 900–4; Alberts, "Essential cell biology", Garland Science, 2010, p. 120–70 (original not read by us) en.wikipedia.org
- Wikipedia, "Protein folding" (CC BY-SA 4.0), which cites: "The formation and stabilization of protein structure", The Biochemical Journal, July 1972, p. 737–49 (original not read by us) en.wikipedia.org
- Al-Karadaghi, "Torsion Angles and the Ramachnadran Plot in Protein Structures", www.proteinstructures.com. facts only, no text reused. proteinstructures.com
- Marusich, "Chaperones in bacteriophage T4 assembly", Biochemistry. Biokhimiia, April 1998, p. 399–406. facts only, no text reused. protein.bio.msu.ru
- "Structural Biochemistry/Proteins/Protein Folding - Wikibooks, open books for an open world", en.wikibooks.org. facts only, no text reused. en.wikibooks.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Protein folding (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Protein folding (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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