Allophycocyanin: Difference between revisions
Ann Taylor (talk | contribs) New page: 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,... |
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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 phycocyanobilin. | ||
<Structure load='1all' size=' | <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 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. | ||
Revision as of 15:46, 2 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 phycocyanobilin.
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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 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.
