Fungus crystal provides crucial missing evolutionary link of life

January 3rd, 2008 - 2:07 pm ICT by admin  

London, January 3 (ANI): Studying the crystal structure of a molecule from a primitive fungus has given scientists a significant understanding about how evolution advanced from RNA to more complex life forms.

Researchers from the Purdue University and the University of Texas at Austin made this breakthrough by studying the three-dimensional version of the fungus protein bound to an RNA molecule.

“Now we can see how RNA progressed to share functions with proteins. This was a critical missing step,” Nature magazine quoted Alan Lambowitz, director of the University of Texas Institute for Cellular and Molecular Biology, as saying.

Purdue structural biologist Barbara Golden added: “It’s thought that RNA, or a molecule like it, may have been among the first molecules of life, both carrying genetic code that can be transmitted from generation to generation and folding into structures so these molecules could work inside cells.”

She went on: “At some point, RNA evolved and became capable of making proteins. At that point, proteins started taking over roles that RNA played previously - acting as catalysts and building structures in cells.”

The researcher said that this progress could not be made without seeing how the fungus protein worked.

“Obviously, we can’t see the process of moving from RNA to RNA and proteins and then to DNA, without a time machine. But by using this fungus protein, we can see this process occurring in modern life,” Golden said.

She further said that looking at the crystal revealed two thingsone that this protein uses two completely different molecular surfaces to perform its two roles, and the other that the protein seems to perform the same job that RNA performed in other simple organisms.

“The crystal structure provides a snapshot of how, during evolution, protein molecules came to assist RNA molecules in their biological functions and ultimately assumed roles previously played by RNA,” Golden said.

The researchers revealed that the protein found in the fungus had adapted to take over some of the RNA molecule’s chemical reaction jobs inside cells. They said that the protein stabilizes the RNA molecule called an intron, so that the RNA could cut out non-functional genetic material, and splice together the ends of a functional gene.

The RNA molecule in our study is capable of performing a specific chemical reaction on itself, but it requires a protein for this reaction to take place efficiently,” said Paul Paukstelis, lead author and a research scientist at the Texas institute.

Lambowitz believes that the basic scientific information may ultimately lead to clinical applications.

“This work has potential applications in the development of anti-fungal drugs to battle potentially deadly pathogens; that’s one of the next steps. Another is to produce more detailed structures so that we can understand the ancient chemical reactions,” he said. (ANI)

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