Genome complexity: fixing ribosome crashes (Introduction)

by David Turell , Wednesday, March 09, 2022, 20:19 (775 days ago) @ David Turell

A new study in bacteria and yeast:

https://phys.org/news/2022-03-ribosomes-collide-bacteria-molecular.html

"Molecular machines known as ribosomes quite literally follow instructions encoded in a linear strand of genetic material. As they travel along the strand, they build a protein. Sometimes, though, this machinery malfunctions.

"Earlier research in yeast, whose cells resemble those of animals, had shown that ribosomes stall when they get into trouble. Like a car that stops too suddenly, a stalled ribosome can be rear-ended by the one behind it. Green's lab had previously identified a yeast molecule that responds to these collisions. Like a tiny Jaws of Life, the molecule cuts the stalled ribosome free. It's the first step in a rescue effort that ultimately lets the cell salvage and reuse these valuable, protein-making machines.

"Bacterial cells' ribosomes can get jammed up too, but scientists doubted that bacteria respond to collisions the same way yeast do. That's because researchers already knew that bacteria have their own distinct method for rescuing wrecked ribosomes, says Jamie Cate, a biochemist and structural biologist at the University of California, Berkeley, who was not involved in the project.

"No one knew exactly what kicked off the bacterial rescue effort, but they expected that it would be something entirely different from yeast, Cate says. Instead, the new research suggests that both bacteria and yeast initiate this process the same way—by summoning blade-like first responders.

***

"In Green's lab in Baltimore, Buskirk and first author Kazuki Saito identified the first responder in bacteria as a molecule called SmrB and explored how it carried out its job. Beckmann's structure "was the final piece of the puzzle," Buskirk says.

***

"Biochemical experiments revealed that SmrB, like its yeast counterpart, cuts the wrecked ribosomes apart. And not only do the two molecules share a job description, bacterial SmrB and its yeast counterpart are also close relatives, the team found. Researchers haven't yet been able to visualize how the yeast version interacts with ribosomes during a collision. So, the similar but simpler SmrB may give scientists a foothold for understanding how the process works in other organisms.

"'Everything else about these rescue pathways is very different," Green says. "We didn't anticipate we would find an aspect that appears to be universal.'"

Comment: this system must be universal or life would end. This is like all the other editing systems discovered. They had to be present at the initiation of DNA coding and decoding. For me it clearly shows God, the designer, recognized in his design where trouble could happen from molecular mistakes