Friday, January 23, 2009

Origins 6, ATPase



All living organisms have in common certain mechanisms for producing energy to supply for their metabolic needs. One of the sets of molecules is called ATP Synthase, or ATPase. This picture is from the Research Collaboratory for Structural Bioinformatics. It shows the "machine" that puts a high-energy piece onto a lower-energy molecule (ADP). The energetic ATP then supports various chemical reactions. It is necessary for the reproduction of DNA and the production of proteins.

This molecule has over 60,000 atoms. (I added up the amino acids of all the parts of the bacterial E. coli ATPase and got over 6,400 amino acids.) There are thousands of these machines in each cell of every organism, and they are assumed to be little changed through evolution.

The second picture shows some aspects of the mechanism. There are hydrogen protons (hydrogen atoms without their electron) on the outside of the membrane to which the molecules are attached. The protons have been pumped outside the membrane, so there is a gradient of postive to negative charges. The protons are attracted to the negative charges and lower concentrations of protons inside the membrane. They come back through the ATP Synthase molecule, which turns it. The mechanism attaches ADP and a separate molecule to it and combines the two to form ATP. This in turn has the high energy needed for cell metabolism.


So, we have three domains with some pretty major differences, just a few of which I mentioned in previous posts. They have large percentages of different proteins with structures in the thousands of atoms. But they all have this super-complex energy machine. That pretty effectively eliminates separate "chance" formations of each of the three domains. So that is why the Last Unknown Common Ancestor (LUCA) has been proposed. This would be a single organism that could give rise to all the others.

The other possibility, say some, is that molecules floated around loosely, having their own lives, and then "mixed and matched" as they formed into each of the Domains. For the ATP Synthase, this seems pretty unlikely, since it needs the membrane and concentration gradient of ions in order to work. It comes under the heading named by Michael Behe of "Irreducibly Complex."

Materialistic evolutionists argue that proteins have "other jobs" before they get to the functions that we see and study today. But ATP synthase is needed by the cell for the energy to break down food and make DNA, RNA, proteins and other molecules of the cell. Though there are sources of energy like the sun and oceanic thermal vents, the energy must be controlled and directed. A river can't make cars. However the energy from a river can be harnessed to create electricity and thereby run the factory that makes cars. Lightening is very powerful, but does not construct delicate arrangements of atoms and molecules. Without cellular conversion of energy to bring a steady supply of building blocks and small energy packets to the assembly lines of cells, there are no "other jobs" for proteins.

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