The experimental design for the lac operon, Walter Gilbert
Interviewee: Walter Gilbert. Walter Gilbert describes how they did the experiment to isolate the lac operon repressor. (DNAi Location: Code > Controlling the code > Players > Walter Gilbert > Isolating the repressor)
We knew that the molecule should interact with the sugar that was coming into the cell. And so we could use a radioactive form of that sugar to try to look for a molecule that it interacted with inside the bacterial cell. We knew that interaction was, we knew something about the strength of that interaction and we could actually decide that interaction was probably too weak for us to be able to see it. So Benno Muller-Hill modified the bacteria, made a mutation, a genetic mutation, that changed the way in which the repressor bound to the small molecule we call an inducer, and made a mutation so the repressor now worked more tightly, bound to the inducer at a lower concentration. And then we took those bacteria, and looked for the interaction between the, a protein and the small molecule, by using a radioactive small molecule, and asking actually, we put the protein inside a little sack that the small molecule could move in and out of, could we find an excess of molecules bound inside the sack because they were attached to the protein. And we actually made that experiment work.
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- ID: 15254
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15253. Discovering the lac operon, Walter Gilbert
Walter Gilbert talks about identifying the lac operon repressor.
15276. Genes control the structure of proteins, François Jacob
François Jacob talks about Genes control the structure of proteins
15269. The discovery of the lac operon, François Jacob
François Jacob talks about how enzyme production was viewed at the time they were beginning their experiments.
15684. Jacob's lac operon drawing
Small image of François Jacob's lac operon drawing.
15255. Producing human insulin using recombinant DNA, Walter Gilbert
Walter Gilbert talks about the reasons for making insulin with recombinant DNA.
15271. Discovering the lac operon, François Jacob
François Jacob talks about bacterial mutants that could not metabolize lactose. Using these mutants, Jacob and Monod figured out how protein production is controlled.
15884. The lac operon
Francois Jacob and Jaçques Monod figured out how bacteria controlled the production of an enzyme called beta-galactosidase. This system of feedback and negative regulation became the lac operon and was the first model for the control of protein productio
16688. Animation 33: Genes can be turned on and off.
Jacques Monod and François Jacob work with how bacteria breaks large sugars into smaller pieces.
15256. Producing rat insulin using recombinant DNA, Walter Gilbert
Walter Gilbert talks about his group's early success with isolating the rat insulin gene and making recombinant rat insulin.
16395. Animation18: Bacteria and viruses have DNA too.
Joshua Lederberg worked with bacterial genetics while Alfred Hershey showed that DNA is responsible for the reproduction of new viruses in a cell.