Convergent Evolution of Cytochrome c6 and Plastocyanin
Cytochrome c6 and plastocyanin are an excellent case study of the convergent evolution of proteins. The two molecules differ in their primary sequence and 3D structure but function in a similar way to transfer electrons from cytochrome b 6 f to Photosystem I. It seems that cytochrome c6 was first “discovered” by Nature when iron was much more available than copper because of the reducing character of the Earth’s atmosphere. As the atmospheric molecular oxygen concentration began to rise because of photosynthetic activity, the relative bioavailabilities of iron and copper declined and rose, respectively, and cytochrome c6 was replaced with plastocyanin.
KeywordsHeme Protein Copper Protein Synechococcus Elongatus Donor Protein Plant Cytochrome
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