Nucleic Acids and the Genetic Material Problem Set 1

Problem 11: Products after protein synthesis

A synthetic mRNA of repeating sequence 5'-CACACACACACACACAC... is used for a cell-free protein synthesizing system like the one used by Nirenberg. If we assume that protein synthesis can begin without the need for an initiator codon, what product or products would you expect to occur after protein synthesis?

Deciphering the genetic code

  • Nirenberg and Matthaei

    1. Developed a method for in vitro protein synthesis requiring added mRNA.

    2. Khorana and Nirenberg laboratories synthesized synthetic polymers of RNA.

    3. Poly "U" or UUUUUUUUUUU codes for a protein containing only phenylalanine.

    4. Poly "CA" codes for alternating histidine-threonine polypeptides.

    5. Poly "CAA" codes for three polypeptides: polyglutamine, polythreonine, or polyasparagine.

  • Complete determination of the code came when they observed that an AA-tRNA would bind to a single synthetic codon in the presence of ribosomes.

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Sunday, September 29, 1996
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