Protein folding
From Wikipedia, the free encyclopedia
Protein folding is the process by which a protein gets its functional shape or 'conformation'. It is mainly a self-organising process. Starting from a random coil, polypeptides fold into their characteristic working shape.[1] The structure is held together by hydrogen bonds.
The stages are:
- Each protein exists as an unfolded polypeptide or random coil when translated from a sequence of mRNA to a linear chain of amino acids. This polypeptide lacks any developed three-dimensional structure (left hand side of the top figure).
- Amino acids interact with each other to produce a well-defined three-dimensional structure, the folded protein (right hand side of the figure). This is known as the native state. The resulting three-dimensional structure is determined by the amino acid sequence (Anfinsen's dogma).[2]
Without its correct three-dimensional structure a protein does not work. However, some parts of proteins may not fold: this is normal.[3]
If proteins do not fold into their native shape, they are inactive and are usually toxic. Several diseases are believed to result from misfolded proteins.[4] Many allergies are caused by the folding of the proteins, for the immune system does not produce antibodies for all possible protein structures.[5]
References [change]
- ↑ Alberts, Bruce et al (2002). "The shape and structure of proteins". Molecular biology of the cell. New York: 4th ed, Garland Science. ISBN 0-8153-3218-1.
- ↑ Anfinsen C. (1972). "The formation and stabilization of protein structure". Biochem. J. 128 (4): 737–49. PMC 1173893. PMID 4565129.
- ↑ Berg, Jeremy M; Tymoczko, John L. & Stryer, Lubert. Web content by Neil D. Clarke (2002). "3. Protein structure and function". Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4684-0. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=books&doptcmdl=GenBookHL&term=stryer%5Bbook%5D+AND+215168%5Buid%5D&rid=stryer.chapter.280.
- ↑ Selkoe, Dennis J. (2003). "Folding proteins in fatal ways". Nature 426 (6968): 900–904. doi:10.1038/nature02264. PMID 14685251. http://www.nature.com/nature/journal/v426/n6968/full/nature02264.html.
- ↑ Alberts, Bruce et al 2010. Protein structure and function. In Essential cell biology. 3rd ed, New York: Garland Science, 120-170.
