Allophycocyanin
From Proteopedia
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| - | Blue-green algae such as ''Spirulina'' maximize their light harvesting ability by using phycobiliproteins to absorb light over a broader spectrum. One of these proteins, allophycocyanin, can be seen on the right. It contains a chromophore called phycocyanobilin. | + | Blue-green algae such as ''Spirulina'' maximize their light harvesting ability by using phycobiliproteins to absorb light over a broader spectrum. One of these proteins, allophycocyanin, can be seen on the right. It contains a chromophore called <scene name='Allophycocyanin/Pigment/1'>phycocyanobilin</scene>. |
<Structure load='1all' size='300' frame='true' align='right' caption='allophycocyanin' scene='Insert optional scene name here' /> | <Structure load='1all' size='300' frame='true' align='right' caption='allophycocyanin' scene='Insert optional scene name here' /> | ||
| - | Allophycocyanin is a primarily alpha-helical protein. It contains two subunits, which each have one phycocyanobilin. Allophycocyanin has a complex quaternary structure. First, trimers of the dimers form in a circular fashion, then stack on top of each other to form an antenna-like structure called the phycobilisome. | + | Allophycocyanin is a primarily <scene name='Allophycocyanin/2ndary_structure/2'>alpha-helical</scene> protein. It contains <scene name='Allophycocyanin/Subunits/2'>two subunits</scene>, which each have one phycocyanobilin. Allophycocyanin has a complex quaternary structure. First, trimers of the dimers form in a circular fashion, then stack on top of each other to form an antenna-like structure called the phycobilisome. |
Allophycocyanin holds the pigment in place through a number of intermolecular interactions. | Allophycocyanin holds the pigment in place through a number of intermolecular interactions. | ||
Revision as of 15:02, 4 November 2011
Blue-green algae such as Spirulina maximize their light harvesting ability by using phycobiliproteins to absorb light over a broader spectrum. One of these proteins, allophycocyanin, can be seen on the right. It contains a chromophore called .
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Allophycocyanin is a primarily protein. It contains , which each have one phycocyanobilin. Allophycocyanin has a complex quaternary structure. First, trimers of the dimers form in a circular fashion, then stack on top of each other to form an antenna-like structure called the phycobilisome.
Allophycocyanin holds the pigment in place through a number of intermolecular interactions.
Interestingly, the λmax of the chromophore can be tuned depending upon the protein binding it. For allophycocyanin, the λmax is 650 nm; in another phycobiliprotein, phycocyanin, the λmax is 625 nm, even though it uses the same chromophore. Phycocyanobilin is a highly flexible, linear tetrapyrrole that is covalently attached to the protein by a thiol linkage to a cysteine in the protein.
