The RNA Tie Club was an informal scientific club, meant partly to be humorous, [1] of select scientists who were interested in how proteins were synthesised from genes, specifically the genetic code. [2] It was created by George Gamow upon a suggestion by James Watson in 1954 [2] when the relationship between nucleic acids and amino acids in genetic information was unknown. The club consisted of 20 full members, each representing an amino acid, and four honorary members, representing the four nucleotides. The function of the club members was to think up possible solutions and share with the other members.
The first important document of the RNA Tie Club was Francis Crick's adaptor hypothesis in 1955. Experimental work on the hypothesis led to the discovery of transfer RNA, a molecule that carries the key to genetic code. Most of the theoretical groundwork and preliminary experiments on the genetic code were done by the club members within a decade. However, the specific code was discovered by Marshall Nirenberg, a non-member, who received Nobel Prize in Physiology or Medicine in 1968 for the discovery.
In 1953, English biophysicist Francis Crick and American biologist James Watson, working together at the Cavendish Laboratory of the University of Cambridge, deduced the structure of DNA, the principal genetic material of organisms, [3] thought to link genetic information in DNA to proteins. [4] By 1954, it was becoming understood that the genetic information pathway involved DNA, RNA and proteins. However, the structure and nature of RNA were still a mystery (specific RNA molecules were not known until 1960 [5] ), especially how RNA is involved in protein synthesis. [6] Watson called this problem "the mystery of life" in his letter to Crick. [5]
Soviet-American physicist George Gamow at George Washington University suggested the first scheme for protein synthesis from DNA. [7] [8] In early 1954, he spent several days at Woods Hole on Cape Cod with Crick, Watson and Sydney Brenner, discussing genetics. [2] Based on the Watson-Crick model, he proposed a "direct DNA template hypothesis" stating that proteins are synthesised directly from the double-stranded grooves of DNA. [9] The four bases of DNA were assumed to synthesise 20 different amino acids as triplets with overlapping nucleotide sequences. [10] He published the hypothesis in the 13 February 1954 issue of Nature , explaining:
It seems to me that such translation procedure can be easily established by considering the 'key-and-lock' relation between various amino-acids, and the rhomb-shaped 'holes' formed by various nucleotides in the deoxyribonucleic acid chain... One can speculate that free amino-acids from the surrounding medium get caught into the 'holes' of deoxyribonucleic acid molecules, and thus unite into the corresponding peptide chains. [11]
In May 1954, Watson visited Gamow, who was on sabbatical at the University of California, Berkeley. While discussing Gamow's hypothesis, he suggested that they form a 20-member club to work out the genetic code. [2] Gamow instantly came up with the RNA Tie Club to "solve the riddle of the RNA structure and to understand how it built proteins", adding the motto "do or die; or don't try." [12]
The club thus consisted of 20 eminent scientists, each of whom corresponded to an amino acid, plus four honorary members (S. Brenner, VAL. F. Lipmann, A. Szent-Gyorgyi, and another individual), one for each nucleotide. [12]
Each member received a woolen necktie having an embroidered helix, hence the name "RNA Tie Club". [12]
Member | Training | RNA Tie Club Designation | Officer designation |
---|---|---|---|
George Gamow | Physicist | ALA | Synthesizer |
Alexander Rich | Biochemist | ARG | Lord Privy Seal of the British Cabinet |
Paul Doty | Physical Chemist | ASP | |
Robert Ledley | Mathematical Biophysicist | ASN | |
Martynas Ycas | Biochemist | CYS | Archivist |
Robley Williams | Electron Microscopist | GLU | |
Alexander Dounce | Biochemist | GLN | |
Richard Feynman | Theoretical Physicist | GLY | |
Melvin Calvin | Chemist | HIS | |
Norman Simmons | Biochemist | ILE | |
Edward Teller | Physicist | LEU | |
Erwin Chargaff | Biochemist | LYS | |
Nicholas Metropolis | Physicist, Mathematician | MET | |
Gunther Stent | Physical Chemist | PHE | |
James Watson | Biologist | PRO | Optimist |
Harold Gordon | Biologist | SER | |
Leslie Orgel | Theoretical Chemist | THR | |
Max Delbrück | Theoretical Physicist | TRP | |
Francis Crick | Physicist | TYR | Pessimist |
Sydney Brenner | Biologist | VAL |
Members of the RNA Tie Club received a black wool-knit tie with a green and yellow RNA helix emblazoned on it. The original design of the tie came from Orgel, with the final pattern re-imagined by Gamow. [12] Gamow's tie pattern was delivered to a Los Angeles haberdasher on Colorado Avenue by Watson, with the shop tailor promising to make the ties for $4 each. [13] Along with each tie, members of the club were to receive a golden tiepin with the three letter abbreviation of their club amino acid designation. Not all members may have received their pin. Gamow, however, wore his pin on several occasions, often causing confusion and questioning of why he was wearing the "wrong initials". [13]
The RNA Tie Club never had a formal meeting of all its members. [2] Members visited each other to discuss the scientific developments, usually involving cigars and alcohol. This allowed bonding and close friendships to develop among this scientific elite, and it turned out to be a breeding ground for creative ideas. The members mailed letters and preprints of articles to each other suggesting new concepts and ideas. [14]
Using mathematics, Gamow postulated that a nucleotide code consisting of three letters (triplets) would be enough to define all 20 amino acids. [11] This concept is the basis of "codons", and set an upper and lower limit on their size. Gamow had simply estimated that the number of bases and their complementary pairs in a DNA strand could create 20 cavities for amino acids, meaning that 20 different amino acids could be involved in protein synthesis. [15] He named this DNA–protein interaction the "diamond code." [16] Although Gamow's premise that DNA directly synthesized proteins was proven wrong, [10] the triplet code became the foundation of genetic code. [16]
Sydney Brenner proposed the concept of the codon, the idea that three non-overlapping nucleotides could code for one amino acid. [17] His proof involved statistics and experimental evidence from amino acid protein sequences.
Francis Crick proposed the "adaptor hypothesis" (a name given by Brenner [18] ) suggesting that some molecule ferried the amino acids around, and put them in the correct order corresponding to the nucleic acid sequence. [19] The hypothesis contradicted Gamow's direct DNA template hypothesis, positing that DNA could not synthesise proteins directly, but instead requires other molecules, adaptors to convert the DNA sequences to amino acid sequences. He also suggested that there were such 20 separate adaptor molecules. [20] [21] This was later confirmed by Robert Holley and the adaptor molecules were named transfer RNAs (tRNAs). [22]
The typed paper distributed to the members of the RNA Tie Club in January 1955 as "On Degenerate Templates and the Adaptor Hypothesis: A Note for the RNA Tie Club" is described as "one of the most important unpublished articles in the history of science", [23] [24] and "the most famous unpublished paper in the annals of molecular biology." [24] Watson recalled, "The most famous of these [unpublished] notes, by Francis, in time would totally change the way we thought about protein synthesis. [2]
Six members of the RNA Tie Club became Nobel laureates: Richard Feynman, Melvin Calvin, James Watson, Max Delbruck, Francis Crick and Sydney Brenner. However, the ultimate goal of understanding and deciphering the code linking nucleic acids and amino acids was achieved by Marshall Nirenberg, who was not a member of the RNA Tie Club, [25] and received the Nobel Prize in Physiology or Medicine in 1968 with Holley and Har Gobind Khorana. [26]
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. Dictated by specific hydrogen bonding patterns, "Watson–Crick" base pairs allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA. The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and RNA polymerase transcribes DNA into RNA. Many DNA-binding proteins can recognize specific base-pairing patterns that identify particular regulatory regions of genes.
Francis Harry Compton Crick was an English molecular biologist, biophysicist, and neuroscientist. He, James Watson, Rosalind Franklin, and Maurice Wilkins played crucial roles in deciphering the helical structure of the DNA molecule.
The genetic code is the set of rules used by living cells to translate information encoded within genetic material into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries.
The Hershey–Chase experiments were a series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material.
Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is deoxyribose, a variant of ribose, the polymer is DNA.
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.
The central dogma of molecular biology is an explanation of the flow of genetic information within a biological system. It is often stated as "DNA makes RNA, and RNA makes protein", although this is not its original meaning. It was first stated by Francis Crick in 1957, then published in 1958:
The Central Dogma. This states that once "information" has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information here means the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein.
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nucleotides. By convention, sequences are usually presented from the 5' end to the 3' end. For DNA, with its double helix, there are two possible directions for the notated sequence; of these two, the sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the primary structure.
Sydney Brenner was a South African biologist. In 2002, he shared the Nobel Prize in Physiology or Medicine with H. Robert Horvitz and Sir John E. Sulston. Brenner made significant contributions to work on the genetic code, and other areas of molecular biology while working in the Medical Research Council (MRC) Laboratory of Molecular Biology in Cambridge, England. He established the roundworm Caenorhabditis elegans as a model organism for the investigation of developmental biology, and founded the Molecular Sciences Institute in Berkeley, California, United States.
A wobble base pair is a pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules. The four main wobble base pairs are guanine-uracil (G-U), hypoxanthine-uracil (I-U), hypoxanthine-adenine (I-A), and hypoxanthine-cytosine (I-C). In order to maintain consistency of nucleic acid nomenclature, "I" is used for hypoxanthine because hypoxanthine is the nucleobase of inosine; nomenclature otherwise follows the names of nucleobases and their corresponding nucleosides. The thermodynamic stability of a wobble base pair is comparable to that of a Watson-Crick base pair. Wobble base pairs are fundamental in RNA secondary structure and are critical for the proper translation of the genetic code.
The Nirenberg and Matthaei experiment was a scientific experiment performed in May 1961 by Marshall W. Nirenberg and his post-doctoral fellow, J. Heinrich Matthaei, at the National Institutes of Health (NIH). The experiment deciphered the first of the 64 triplet codons in the genetic code by using nucleic acid homopolymers to translate specific amino acids.
The Nirenberg and Leder experiment was a scientific experiment performed in 1964 by Marshall W. Nirenberg and Philip Leder. The experiment elucidated the triplet nature of the genetic code and allowed the remaining ambiguous codons in the genetic code to be deciphered.
Marshall Warren Nirenberg was an American biochemist and geneticist. He shared a Nobel Prize in Physiology or Medicine in 1968 with Har Gobind Khorana and Robert W. Holley for "breaking the genetic code" and describing how it operates in protein synthesis. In the same year, together with Har Gobind Khorana, he was awarded the Louisa Gross Horwitz Prize from Columbia University.
A gene product is the biochemical material, either RNA or protein, resulting from expression of a gene. A measurement of the amount of gene product is sometimes used to infer how active a gene is. Abnormal amounts of gene product can be correlated with disease-causing alleles, such as the overactivity of oncogenes which can cause cancer. A gene is defined as "a hereditary unit of DNA that is required to produce a functional product". Regulatory elements include:
The history of molecular biology begins in the 1930s with the convergence of various, previously distinct biological and physical disciplines: biochemistry, genetics, microbiology, virology and physics. With the hope of understanding life at its most fundamental level, numerous physicists and chemists also took an interest in what would become molecular biology.
The adaptor hypothesis is a theoretical scheme in molecular biology to explain how information encoded in the nucleic acid sequences of messenger RNA (mRNA) is used to specify the amino acids that make up proteins during the process of translation. It was formulated by Francis Crick in 1955 in an informal publication of the RNA Tie Club, and later elaborated in 1957 along with the central dogma of molecular biology and the sequence hypothesis. It was formally published as an article "On protein synthesis" in 1958. The name "adaptor hypothesis" was given by Sydney Brenner.
The sequence hypothesis was first formally proposed in the review "On Protein Synthesis" by Francis Crick in 1958. It states that the sequence of bases in the genetic material determines the sequence of amino acids for which that segment of nucleic acid codes, and this amino acid sequence determines the three-dimensional structure into which the protein folds. The three-dimensional structure of a protein is required for a protein to be functional. This hypothesis then lays the essential link between information stored and inherited in nucleic acids to the chemical processes which enable life to exist.
Nucleic acid analogues are compounds which are analogous to naturally occurring RNA and DNA, used in medicine and in molecular biology research. Nucleic acids are chains of nucleotides, which are composed of three parts: a phosphate backbone, a pentose sugar, either ribose or deoxyribose, and one of four nucleobases. An analogue may have any of these altered. Typically the analogue nucleobases confer, among other things, different base pairing and base stacking properties. Examples include universal bases, which can pair with all four canonical bases, and phosphate-sugar backbone analogues such as PNA, which affect the properties of the chain . Nucleic acid analogues are also called Xeno Nucleic Acid and represent one of the main pillars of xenobiology, the design of new-to-nature forms of life based on alternative biochemistries.
Alexander Latham Dounce was an American professor of biochemistry. Among his fields of study were the isolation and purification of cellular organelles, protein crystallization, enzymes, DNA binding proteins, and the chemical basis of protein synthesis. He also invented the Dounce homogenizer, which was named after him.
In molecular biology, hybridization is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules anneal to complementary DNA or RNA. Though a double-stranded DNA sequence is generally stable under physiological conditions, changing these conditions in the laboratory will cause the molecules to separate into single strands. These strands are complementary to each other but may also be complementary to other sequences present in their surroundings. Lowering the surrounding temperature allows the single-stranded molecules to anneal or “hybridize” to each other.