Beta sheet
From Proteopedia
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===Beta sheets in soluble (globular) proteins=== | ===Beta sheets in soluble (globular) proteins=== | ||
===Beta sheets in transmembrane proteins=== | ===Beta sheets in transmembrane proteins=== | ||
| - | ===Beta sheets in | + | ===Beta sheets in amyloid fibrils=== |
==History== | ==History== | ||
| + | Alpha helices and beta sheets are named after two conformations of keratin, a fiber occuring in mammals (wool, hair, quills) <ref>PMID: 15240497</ref>. Alpha keratin is composed of [[coiled coils]] of alpha helices, whereas hard stretching these fibers in water changes the conformation to beta sheets. The two conformations show different diffraction data under X-ray illumination. | ||
==Experimental evidence== | ==Experimental evidence== | ||
| + | Apart from the historical fiber diffraction data, various spectroscopic techniques may be used to show the presence of beta sheets. Circular dichroism (CD) or infrared (IR) spectroscopy allows an estimate of the beta sheet content of a protein sample. NMR spectroscopy, after resonance assignment, allows secondary structure assignment residue by residue based on chemical shifts of the alpha carbon and beta carbon resonances. | ||
==Quiz== | ==Quiz== | ||
==See Also== | ==See Also== | ||
==References== | ==References== | ||
| + | {{Reflist}} | ||
Revision as of 08:53, 7 August 2021
A beta sheet is a type of secondary structure, i.e. a description of how the main chain of a protein is arranged in space. It is composed of at least two beta strands. Beta strands have repetitive regular secondary structure (just like the alpha helix), i.e. all residues have similar conformation and hydrogen bonding, and it can be of arbitrary length.
Contents |
Your Heading Here (maybe something like 'Structure')
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Connectedness or topology of beta sheets
Types of proteins and folds that contain sheets
Beta sheets in soluble (globular) proteins
Beta sheets in transmembrane proteins
Beta sheets in amyloid fibrils
History
Alpha helices and beta sheets are named after two conformations of keratin, a fiber occuring in mammals (wool, hair, quills) [1]. Alpha keratin is composed of coiled coils of alpha helices, whereas hard stretching these fibers in water changes the conformation to beta sheets. The two conformations show different diffraction data under X-ray illumination.
Experimental evidence
Apart from the historical fiber diffraction data, various spectroscopic techniques may be used to show the presence of beta sheets. Circular dichroism (CD) or infrared (IR) spectroscopy allows an estimate of the beta sheet content of a protein sample. NMR spectroscopy, after resonance assignment, allows secondary structure assignment residue by residue based on chemical shifts of the alpha carbon and beta carbon resonances.
Quiz
See Also
References
- ↑ Kreplak L, Doucet J, Dumas P, Briki F. New aspects of the alpha-helix to beta-sheet transition in stretched hard alpha-keratin fibers. Biophys J. 2004 Jul;87(1):640-7. doi: 10.1529/biophysj.103.036749. PMID:15240497 doi:http://dx.doi.org/10.1529/biophysj.103.036749
