Does everyone like to breathe? Of course they do! Well, then everyone should love this protein. How is this protein important? Well, in order for there to be enough oxygen for everyone, plants, algae and bacteria need to be able to have oxygen evolving complexes, which break down water to form oxygen. However, for this to occur, there needs to be chlorophyll molecules to absorb photons. This is where this protein is important. It catalyzes the determining step in the production of chlorophyll. What happens is that there is a double bond in a molecule called protochlorophyllide. Once reduced to a single bond, the molecule is chlorophyllide, which is the direct precursor of chlorophyll. This is only the light-independent version of the protein. There is also a light-dependent version found in angiosperms (flowering plants) which requires light and light reactions to function.
Chlorophyll
Picture provided by http://www.secchidipin.org/chlorophyll.htm
To put this all into perspective, most life could not occur without this protein. All of the reactions that occur in the membranes of chloroplasts could not occur. And as the light reactions of photosynthesis could not occur, ATP could not be made to power the Calvin-Benson Cycle. This means that CO
2 could not be fixed by RuBisCO and sugars could not be made. This means that animals (including humans) would not have food. So next time you take a breath, eat some delicious food or even walk by a tree, remember to be thankful for light-independent protochlorophyllide reductase.
Picture provided by http://www.co.marshall.ia.us/zenphoto/conservation/forest+floor.JPG.php
