Origin of the RNA code, Marshall Nirenberg
Interviewee: Marshall Nirenberg. Marshall Nirenberg talks about origin of the RNA code.
The code is as old as, almost as old as, the first forms of life that originated. Now there's one problem that has never been answered in the code, that still is unanswered that maybe somebody will, who's listening to this will be able to solve, and that is how did the code originate. Why is there a reason why U, U, U codes for poly... for phenylalanine, could it be a different codon, is there a physical reason for the code? One thing I noticed early on was that chemically similar amino acids have chemically similar codons and this is very, very evident and one consequence of this is that a mutation that changes a single base, for example, the effects of this mutation and this amino acid replacement will be minimized if you replace one amino acid by a chemically similar amino acid. And I pointed this out, but nobody really has yet explained the, this underlying order that exists in the code. Did the code evolve from a series of precursor codes? Nobody really knows. Or was it a, a rare, one rare event that occurred, and then was maintained throughout evolution? So I would say the code, you know, is hundreds of millions of years, maybe billions of years old and the code originated as life, as life originated.
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After decoding the "easy" codons, Marshall Nirenberg talks about his strategy for decoding the rest.
Marshall Nirenberg talks about the RNA code for phenylalanine.
Marshall Nirenberg talks about Gobind Khorana, who synthesized many of the triplets needed to finish the decoding process.
Having made phenylalanine using poly-U mRNA, Marshall Nirenberg still had to prove it. He talks about how he did this with help from a fellow scientist â Michael Siler.
Marshall Nirenberg, Har Gobind Khorana, and Robert Holley shared the 1968 Nobel Prize for Physiology and Medicine. Nirenberg and Khorana cracked the genetic code. Holley sequenced and deduced the structure of the first tRNA molecule.
Several researchers crack the genetic code.
Decode a protein.
Marshall Nirenberg and Heinrich Matthaei used poly-U mRNA in a cell-free system to make a polyphenylalanine protein chain. This showed that UUU must be the code that specifies the amino acid phenylalanine.
Marshall Nirenberg talks about the contributions of Maxine Singer, Marianne Grunberg-Monago and Phil Leder.
Marshall Nirenberg talks about cell-free protein synthesis.