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Earlier this year, scientists reported discovering a protein that allowed a bacterium, Psychrobacter urativorans, to abruptly shut down in unfavourable living conditions and ‘restart’ just as quickly when they improved.
Scientists have known that bacteria become dormant as a result of ribosome hibernation. Ribosomes are the machines that make proteins in cells. In harsh conditions like extremely cold weather, scientists knew there were special proteins that would cover the ribosomes and hinder their activity, shutting the cell. But Balon, the newfound protein, achieves the same thing by doing something else.
According to the new study, published in the journal Nature on February 14, scientists found Balon was bound to the bacterial ribosome’s active centres — the places where the amino acids were ‘loaded’ — thus stopping the ribosomes from making new proteins.
For the experiment, the scientists — with institutions in Hungary, the U.K., and the U.S. — induced cold shock in the P. urativorans bacteria they were studying and then extracted their ribosomes, where they found evidence of inactivated protein synthesis. When they analysed one of the ribosomal sites involved in the process, they found it was occupied by a previously uncharacterised protein. This was Balon.
Unlike the effect of other proteins that helped cells slow or shut down, Balon’s effects were reversible. When the bacteria’s external conditions improved, they simply ejected Balon and resumed protein synthesis.
The discovery is important because, among other things, it could reveal how bacteria survive harsh environments like the Arctic permafrost. Members of the Psychrobacter group of bacteria are particularly infamous for rotting refrigerated food thanks to their ability to weather extreme cold, the study noted.
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Published - June 19, 2024 06:24 pm IST