The Importance of Location
by MikeGeneAcetyl-CoenzymeA (acetyl-CoA) is a central compound of metabolism and an essential building block for the synthesis of fatty acids and amino acids. When cells are growing on glucose, the glucose is broken down to pyruvate, which in turn is converted into acetyl-CoA (by pyruvate dehydrogenase) that is then fed into the Kreb's cycle within mitochondria. An alternative mechanism of generating acetyl-CoA is to use the enzyme acetyl-CoA synthetase, an enzyme that attaches coenzyme A to acetate with the expenditure of ATP.
Yeast have two versions of enzyme acetyl-CoA synthetase, where the 600 amino-acid length proteins share about 60% sequence identity and catalyze the same basic reaction. One version is called Acs1p and when scientists knocked out this gene, nothing much happens. But when the other version, known as Asc2p is knocked out, yeast shut down about 70% of their genes and then die. What's going on?
More
July 25th, 2006 at 12:06 am
Mike,
Thank you. If I may offer a thought here, I think the entire cell could be informational, not just the genome. It's a self-healing architecture and with deep redundancies. This suggests the cell is packed tight with information, probably in the cytoplasm, probably everywhere!
I'm not sure if you were aware of this article about immortal DNA:
Immortal DNA Theory Affirmed
It highlights the importance of location!
Salvador
Comment by Salvador T. Cordova — July 25, 2006 @ 12:06 am
July 25th, 2006 at 3:59 pm
I wonder why they "predicted [Asc2p] to be cytosolic". I'm also a little confused as to why the cells are viable even once all their acetate groups are gone from the chromatin. It might be something else.
Comment by Guts — July 25, 2006 @ 3:59 pm