Scientists find novel enzymes encoded by giant virus

MOSCOW. KAZINFORM - Scientists from Russia and the United States have analyzed the genome and performed proteomic analysis of the giant Bacillus subtilis phage AR9, the Skoltech press service said.

They demonstrated that the phage encodes unusual proteins that are related to RNA polymerases of bacteria, plants, and animals.

"Genes coding for the AR9 RNA polymerases must have been captured by the phage from bacteria long time ago. Now we are studying biochemical mechanism of AR9 RNA polymerases. We already know that they are very different from RNA polymerases from cells", said one of the researchers Maria Sokolova, a PhD student at Konstantin Severinov lab in Skoltech (Russia)

Bacteriophages (phages for short) are viruses that infect bacteria. They consist of proteins shells with viral DNA or RNA packaged inside. Phages replicate within a bacterium following the injection of their genome into the bacterial cell.

There is an enormous amount of phages on our planet and they represent a virtually inexhaustible source of enzymes, which are widely used in biotechnology. Phage-infected bacteria die because of the function of phage proteins. This is why many phage proteins can be used for development of new potent antibiotics. Phage studies also played a major role in the development of the "Central dogma of molecular biology", which describes how all genes work.

The first step of gene function is transcription of DNA into RNA. It is performed by special enzymes - RNA polymerases. All living organisms including bacteriophages have to transcribe their genes. Phages usually employ bacterial RNA polymerase for this function. Russian scientists showed that the AR9 phage is unique, because it uses its own RNA polymerases to transcribe its genes, making the virus independent of host bacterium.

Nos scientists are trying to determine the structure of unusual phage enzymes by X-ray crystallography and cryo-electron microscopy. "A three-dimensional molecular model will answer many questions about the mechanisms and origins of these remarkable enzymes. One day these enzymes may be also used in biotechnology", Sokolova said.

Source: TASS

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