Biologist discusses research
Ada Yonath, Nobel Prize winner and professor of the Weizmann Institute of Science, visited UH giving her lecture, “The Amazing Ribosome.” The speech detailed the findings of work that spanned more than two decades, and led to her becoming the first Israeli woman and only the fourth woman to be recognized as a chemistry laureate.
The lecture was held at the Rockwell Pavilion of the M.D. Anderson Memorial Library.
“I always keep telling our students, the most important thing is that they need passion, and curiosity, and today you’re going to see what that passion and that curiosity can do,” UH President Renu Khator said as she introduced Yonath.
Working independently, Yonath received the 2009 Nobel Prize in chemistry, along with Venkatraman Ramakrishnan and Thomas Steitz, for solving a mystery once dismissed as a theoretical fantasy.
Using X-ray crystallography, they succeeded in mapping the intimate structure and function of the ribosome at the atomic level, revealing the mechanism of peptide bond formation — the bond that links amino acids together in the creation of proteins.
“We saw something that looked like a tunnel … and at the same time another group found it at a much lower resolution,” Yonath said.
According to a Dec. 14 article in scienceblog.com, the groups found the structural center of the ribosome, “a highly symmetrical tunnel that allows for a 180-degree repositioning of the aminoacyl-tRNAs as amino acids are transferred from the tRNA to the growing peptide strand.”
Without ribosomes and the key proteins they produce, life would not be possible. It would be similar to having all of the raw instructions (DNA) necessary for a product, but without having the machines (ribosomes) to put those instructions together.
“What the ribosome does,” Yonath said, “is it translates the genetic code into proteins, and the genetic code is brought to the ribosome by messenger RNA. It is stored in the DNA, but it’s being transcribed to messenger (RNA) and then is translated into proteins.”
Ribosomes are factories for producing proteins, similar to factories that receive instructions on a piece of paper and use trucks called tRNA to ship in and empty the amino acids to be assembled by the code into a protein, Yonath said.
According to the National Institute of General Medical Sciences, X-ray crystallography allows scientists to take molecular snapshots of antibiotics grabbing onto the bacterial ribosome.
Applying these data, they were able to construct 3-D computer models that will now allow researchers to view how more than a dozen different antibiotics bind to the ribosome of the bacteria and block its function.
The use of these models will allow researchers to study how pathogenic bacteria develop resistance to antibiotics and design stronger molecules to fit the bacterial ribosomes more effectively, which will be used to create new life saving drugs.
UH Professor Paul Chu worked with Yonath in the early ‘80s, when they collaborated on a paper after meeting each other at a conference in Hamburg.
“Ada is an extremely enthusiastic scientist who’s absolutely infectious,” Chu said. “I remember, through the collaborations, I flew to Hamburg to see her, and she took me to her lab. Ada was initially heard saying, ‘Let’s get the structure of a ribosome,’ which in those days was almost unthinkable or impossible.”
Thanks to her work, researchers now have a much clearer window into the mechanisms of microbiology, a feat that few believed was a reality, even after the structure was defined.
“If you think this fantastic finding was easily obtained by the ribosomologists, you’re wrong,” Yonath said. “It was felt, and everybody said that we won’t be able to determine the structure. Now, when we came to the tunnel, they said, ‘this lady from the Middle East, this dreamer, now she has a home.’”