Biological complexity: how ribosome makes RNA (Introduction)

by David Turell , Saturday, November 23, 2019, 01:09 (1617 days ago) @ David Turell

It takes lots of different protein molecules to shepherd the assembly:

https://phys.org/news/2019-11-cell-biology-scientists-ribosome-real.html

"'This shows that we now can examine in detail how RNAs fold while they are being synthesized and proteins are assembling on them," says first author Olivier Duss, Ph.D., a postdoctoral research fellow in the Department of Integrative Structural & Computational Biology at Scripps Research. "This has been a very difficult thing to study in biology because it involves several distinct biological processes that are dependent on each other and have to be detected simultaneously."

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"In a proof-of-principle study published last year, the researchers used their approach to record an early, brief and relatively well-studied stage of ribosome assembly from the bacterium E. coli. This involved the transcription, or copying out from its corresponding gene, of a ribosomal RNA, and initial interactions of this RNA strand with a ribosomal protein.

"In the new study, the team extended this approach by tracking not only the transcription of a ribosomal RNA but also its real-time folding. The work provided a detailed look at a complex, and until-now mysterious, part of E. coli ribosome assembly—the formation of an entire major component, or domain, of the E. coli ribosome, with assistance from eight protein partners that end up incorporated into the structure.

"A key finding was that the ribosomal protein partners guide the folding of the RNA strand through multiple temporary interactions with the strand, well before they nestle into their final places in the folded RNA-protein molecule. The findings, according to the researchers, also hint at the existence of unknown RNA assembly factors, most likely proteins, that were not present in their lab-dish-type imaging experiments but are present in cells and boost the efficiency of RNA folding.

"Our study indicates that in ribosomal RNA-folding, and perhaps more generally in RNA-folding in cells, many proteins help fold RNA though weak, transient and semi-specific interactions with it," Duss says."

Comment: A highly complex vital process that requires precise protein activities to produce the correct product. Not by chance.