Synchrotron reveals secret of bendy ribosome
8 Jul 2011 by Evoluted New Media
Scientists have captured the inner workings of ribosomes – the cell’s protein-making machinery – like never before, creating an atom-by-atom map as it carries out its function.
Scientists have captured the inner workings of ribosomes – the cell’s protein-making machinery – like never before, creating an atom-by-atom map as it carries out its function.
|
This “action shot” reveals the motion of the small ribosomal subunit, depicted by difference vectors, during ratcheting. |
As ribosomes are one of the major targets of antibiotics, scientists in America hope to develop drugs to target weak points in the process, hopefully leading to drugs which are less susceptible to resistance.
Researchers from Lawrence Berkeley National Laboratory and colleagues from Cornell and Duke Universities used the Advanced Light Source – a synchrotron at the Berkeley Lab – to determine the structure of Escherichia coli ribosomes in two key states at an atomic resolution.
In the first state, transfer RNA is bound to two subunits in a configuration that occurs after the ribosome has made and released a protein. In the second, the ribosome subunits are fully rotated – which occurs when they are ready to be recycled and used to make another protein.
“This is the first time we’ve seen the ribosome at the endpoint of this motion at this resolution,” said Jamie Cate, associate professor of biochemistry, molecular biology and chemistry at the University of California at Berkeley.
View How protein-making machine bends without breaking to see how the ribosome bends. Find it under Laboratory News Recommends at www.youtube.com/labnews |
The ribosome works like a protein assembly line. Its small subunits move also messenger RNA – which contributes genetic information from the cell’s DNA – and binds to transfer RNA (tRNA), connecting the genetic code on one end with amino acids on the other. A larger unit binds to the tRNA and stitches together the amino acids.
This research has enabled scientists to understand how the ribosome is able to bend and rotate without breaking or tearing the entire ribosome apart. It bends on a hinge – a molecular widget –within tRNA, allowing the tRNA to bend as much as 70° when it passes through the ribosome during protein synthesis.
“Parts of the ribosome are much more flexible that we previously thought,” Cate said. “Now that we have a fully rotational ribosomal structure, scientists may be able to develop new antibiotics that are not as sensitive to ribosomal mutations. This could help mitigate the huge problem of multidrug resistance.”
