Avidin: Difference between revisions
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Avidin is one of the [[CBI Molecules]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst and on display at the [http://www.molecularplayground.org/ Molecular Playground]. | Avidin is one of the [[CBI Molecules]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst and on display at the [http://www.molecularplayground.org/ Molecular Playground]. | ||
<scene name='41/410356/Cv/ | <scene name='41/410356/Cv/15'>Avidin is a tetrameric protein</scene> what in different words means that if we could, we would see a protein with four regions that look identical one to the other. However, to isolate the four regions as a whole in order to show the protein three dimensional structure has been quite diffucult so far and we just can see the three dimensional structure for <scene name='41/410356/Cv/16'>two of those four units</scene>. <ref group="xtra">PMID:8506353</ref><ref group="xtra">PMID:8344421</ref> | ||
{{Clear}} | {{Clear}} | ||
The binding affinity of biotin for the avidin <scene name='41/410356/Cv/ | The binding affinity of biotin for the avidin <scene name='41/410356/Cv/17'>receptors</scene> is very hight or in other words, the strength of the interations between the biotin and the avidin receptors is so strong that washing the biotin-avidin complex is not enough to remove the ligand from its pocket. This is not even possible by adding more biotin molecules to the system avidin-biotin. Once a biotin has bound a pocket in the avidin, it is almost imposible to remove it in a biological system! | ||
Each monomer is an eight-stranded antiparallel <scene name='41/410356/Cv/ | Each monomer is an eight-stranded antiparallel <scene name='41/410356/Cv/18'>beta-barrel</scene>. Binding of biotin involves a highly stabilized network of polar and hydrophobic interactions. | ||
The presence of additional hydrophobic and hydrophilic groups in the binding site of avidin may account for its higher affinity constant. | The presence of additional hydrophobic and hydrophilic groups in the binding site of avidin may account for its higher affinity constant. | ||
Unexpectedly, a residual N-acetylglucosamine moiety was detected in the deglycosylated avidin monomer. These <scene name='41/410356/Cv/ | Unexpectedly, a residual N-acetylglucosamine moiety was detected in the deglycosylated avidin monomer. These <scene name='41/410356/Cv/19'>sugars</scene> appear along with the biotin but outside of the biotin binding pockets. | ||
*<scene name='41/410356/Cv/ | *<scene name='41/410356/Cv/20'>Biotin has bound a pocket in the avidin</scene>. | ||
See also:<br /> | See also:<br /> | ||
* [[Molecular Playground/Streptavidin]] | * [[Molecular Playground/Streptavidin]] | ||