Scientists unveil remarkable editing system for protein production

January 7th, 2008 - 5:29 pm ICT by admin  

London, January 7 (ANI): Scientists at The Scripps Research Institute have come up with two new methods for correcting mistakes made by cells during protein production, which can have profound disease effects.

Professor Paul Schimmel of the Skaggs Institute for Chemical Biology at Scripps Research said that the work led by him might facilitate the identification of underlying causes of various disease, besides providing ways to correct the errors.

He said that his team had found that a completely distinct segment of an enzyme called synthetase, which binds the amino acid alanine in everything from bacteria to humans, acts as a second checkpoint for identifying any incorrect translations done by messenger RNA while it binds amino acids.

This enzyme also removes any amino acid besides alanine that might attach to the alanine transfer RNA, he adds.

According to Schimmel, this second zone within the enzyme focuses its activity on the very same two nucleotides in the genetic code of the transfer RNA used by the first checkpoint, a guanine and uracil pair referred to as G3U70.

“Even such a tiny defect can overwhelm a cell’s ability to deal with misfolded proteins, ultimately causing specific neurological problems,” Nature magazine quoted Scripps Research molecular biologist Kirk Beebe, first author of the new paper with Marissa Mock, as saying.

The researchers have also worked out the functions carried out by certain segments of genome-encoded fragments called as freestanding domains, which till date has been highly debated.

In test tube experiments, they observed that freestanding domains with a genetic sequence very similar to the second checkpoint in the alanine synthetase, known as AlaXp, can independently remove mistranslated amino acids, suggesting that these fragments could also be used as a secondary checkpoint to ensure that defective proteins are not synthesised.

Whether AlaXp actually edits within cells is not certain, and how they could perform such a function is also not yet clear.

“That’s still a question to be resolved. But our work presents a great possibility for how things are likely to occur,” says Beebe.

The group has already begun new experiments to study AlaXp activity in mouse cells.

“The results of the study were a complete surprise to us,” says Schimmel. (ANI)

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