Frederick Sanger

Frederick Sanger OM, CH, CBE ( born August 13, 1918 in Rendcomb, Gloucestershire, † November 19, 2013 in Cambridge, Cambridgeshire ) was a British biochemist.

He was one of the few people who have been honored twice with the Nobel Prize: 1958 Sanger received the Nobel Prize in Chemistry ( as the sole winners ) for the elucidation of the structure of insulin and his work on protein sequencing. In 1980 he was again awarded the Nobel Prize for Chemistry awarded (along with Paul Berg and Walter Gilbert ), this time for studies to determine the base sequence in nucleic acids.

• 2.1 Method for determining the amino acid sequence
• 2.2 Method for sequencing nucleic acids
• 2.3 The importance of Sanger's work in genetic engineering and the Genome Project

Life

Schools and Universities

Frederick Sanger was born as the second son of the physician Frederick Sanger senior and Cicely Sanger. Influenced by his father and by his one year older brother Theodore Sanger developed an early interest in the natural sciences. After education at Bryanston School and at St John's College, Cambridge, he originally wanted to study medicine but opted for biochemistry because it focus more as a scientist, unlike the medical profession on a topic and thus may reach more could. So Sanger began with the study of biochemistry in the Department of Biochemistry at Cambridge.

1939 Sanger received his Bachelor of Arts. Since he came from a Quaker family, he refused to perform military service for reasons of conscience and worked during the Second World War continue working on his doctorate, which he produced lysine in the same institution under the supervision of A. Neuberger on the metabolism of the amino acid. In 1943 he received his doctorate.

Research

Sanger's work was funded from 1944 to 1951 by a Beit Memorial Fellowship for Medical Research. In 1951 he was external staff of the Medical Research Council (MRC ).

In his PhD was Albert Frederick Gowland Hopkins Chibnall 's successor as head of the biochemistry department at Cambridge, and Sanger was a member of Chibnalls research group. The main interest of the group was the chemistry of proteins, especially that of insulin. Sanger eventually developed a method for determining the amino acid sequence, with whose help he the insulin sequence completely certain in twelve years of work. 1955 was published the sequence, for which Sanger was awarded the 1958 Nobel Prize in Chemistry.

As a result, Sanger remained in Cambridge and took over the management of the Department of Protein Chemistry at the Laboratory of Molecular Biology (LMB ). This institute was built in 1962 as a new laboratory complex after the Medical Research Council in 1947 had a group for " research into the molecular structure of biological systems " set up in Cambridge. Although Sanger until then had no particular interest in nucleic acids, he realized through discussion with scientists like Francis Crick and Sydney Brenner, the need to determine the sequence of this other biopolymer. In the following years, Sanger, therefore, addressed the development of another sequencing method, which eventually led to the " Chain termination method ". 1980 Sanger was recognized for his contributions to the sequencing of nucleic acids for the second time the Nobel Prize for Chemistry.

1983 Frederick Sanger retired. Most recently, he devoted himself along with his wife Margaret Joan his hobbies: the gardeners and sailing. From their marriage three children come.

Awards

Work

Method for determining the amino acid sequence

Sanger's method for determining the amino acid sequence was in his time as a member of Albert Chibnalls research group in Cambridge. In the 1940s, the protein chemistry has revolutionized the development of efficient chromatographic separation methods for proteins, peptides and amino acids. Sanger wanted to determine the order of amino acids in a protein ( amino acid sequence). For this purpose he divided the protein chain, first in small peptide fragments and then isolated it using the new methods. For marking and later identifying the terminal amino acid set Sanger fragment peptides with 1-fluoro- 2 ,4-dinitrobenzene to. The N-terminus derivatized peptides were completely cleaved into their amino acids, their relative amounts were then quantified. The identity of the terminal amino acid was determined by chromatographic analysis of the colored dinitrophenyl (DNP) derivative. In this operation, to obtain two pieces of information: first, the identity of the first amino acid in the chain and the second type of the other amino acids in the chain ( although not its position). By multiple repetition of the procedure can finally draw conclusions about the original sequence. The figure illustrates the principle of sequencing method on a small peptide.

In twelve years of work, Sanger succeeded in the complete sequence determination of insulin. To make matters worse, that insulin is a protein consisting of two polypeptide chains that are connected by disulphide bridges. The arrangement of these bridging units also had to be determined. 1955, the complete sequence of insulin was released. This was first proved that proteins have a unique chemical structure. Now earlier hypotheses could be definitively discarded, as the fact that proteins indeed have a defined amino acid composition, but with a random sequence, or even that proteins are aggregates of smaller similar units. 1958 Sanger was honored for this work with the Nobel Prize for Chemistry.

Sanger sequencing method was later replaced by the developed by the Swedish biochemist Pehr Edman phenylisothiocyanate degradation. The main advantage of the Edman method was that you could gradually degrade her and identify amino acids from the N -terminus. The shortened residual peptide is an amino acid could be subjected to a re- reduction cycle, and the sequence thus determined relatively rapidly thereafter.

Method for sequencing nucleic acids

→ Main article: DNA sequencing, dideoxy method of Sanger

Sanger method for sequencing nucleic acids arose during his tenure as head of Department of Protein Chemistry at the Laboratory of Molecular Biology (LMB ) in Cambridge. It arose from the need to determine the sequence of nucleic bases.

Sanger developed to achieve this objective at first a method for sequencing of ribonucleic acids (RNA), which it then to deoxyribonucleic acid ( DNA) anwandte. However, this method was very slow and only permitted the determination of short sequence segments. In the following years he developed a new method that should be the basis for today's DNA sequencing method, called the dideoxy method. This technique uses the following properties of DNA:

Thus, the synthesized DNA piece has a defined beginning. The synthesis products, however, may have different lengths, the length depends on how many free nucleotides synthesis are available, or whether the polymerase accidentally falls off the template strand.

Sanger's trick is to carry out the polymerization reaction in four separate batches, and to ensure that each strand has the same start (which is given by the primers ), and the extension reaction - though at different points - but always at a specific base variety to end. To ensure this, each containing reaction mixture in addition to the four nucleotide monomers each dideoxy variant of a Nukleotidsorte. The chain extension runs until finally sometime a dideoxy nucleotide is incorporated. So that the 3' -OH group is absent for the formation of a phosphodiester bond to the next chain link, and the synthesis stops here. By setting the start point of the length of the synthetic fragments in a reaction mixture reflects the relative position of the respective Nucleinbasensorte in the molecule. Substituting radioactive ( or otherwise marked ) nucleotides to the reaction and separates the four approaches side by side according to their size in an acrylamide gel, so you can read the base sequence directly from the gel. The figure illustrates the principle of dideoxy sequencing.

1977 presented Sanger and employees the complete sequence of the 5,386 base pair bacteriophage φX174. From the sequence of this bacterial virus could directly the amino acid sequence of the ten viral proteins be read because the genetic code indicating which of three sequence of nucleic bases ( base triplet ) for which amino acid encoded in a protein that was known for pioneering work in the 1960s. 1980 Sanger was recognized for his contributions to the sequencing of nucleic acids for the second time with the Nobel Prize.

The importance of Sanger's work in genetic engineering and the Genome Project

Beginning of the 1970s were developed cloning methods, with which one can multiply pieces of DNA of any origin in bacteria, so that sufficient material is available for sequencing are available. This opened up the possibility of all the genetic information of an organism 's genome to be sequenced, and thus indirectly derive the sequences of all theoretically synthesizable by this organism proteins. Along with Stanley Norman Cohen and Paul Berg, the inventors of the recombinant cloning technique, Frederick Sanger can therefore be described as the father of genetic engineering and the genome project.

Quotes

" Of the three main activities Involved in scientific research, thinking, talking, and doing, I much prefer the load and probably the best at it. I am all right at the thinking, but not much good at the talking. "

" Previously I had not had much interest in nucleic acids. I used to go to Gordon Conferences on Protein and Nucleic Acids When the two subjects were bracketed together, and would sit through the nucleic acid talks waiting to get back to proteins. HOWEVER, with people like Francis Crick around, what it difficult to ignore nucleic acids or to fail to realize the, importance of sequencing them. "

" Unlike many scientists, I Decided to retire and give up research When I reached the age of 65 This surprised my colleagues, and to some extent myself so. I had not thought about retirement until I Suddenly Realized 'that' in a few years I would be 65 and would be Entitled to stop work and do some of the things I had always wanted to do and had never had time for. The Possibility Seemed surprisingly attractive, Especially as our work had reached a climax with the DNA sequencing method and I rather felt did to continue would be something of an anticlimax. "

Works

Important papers:

For protein sequencing

• AP Ryle, F. Sanger, R. Kitai: The disulphide bonds of insulin. In: Biochemical Journal. Volume 60, 1955, pp. 541-556; PMID 13249947; PMC 1216151 (Free full text ).

DNA sequencing

• Sanger, F., S. Nicklen, AR Coulson: DNA sequencing with chain -terminating inhibitors. In: Proceedings of the National Academy of Sciences. Volume 74, 1977, p 5463-5467; PMID 271 968; PMC 431 765 (Free full text ).
• F. Sanger, GM Air, BG Barrell, NL Brown, AR Coulson, CA Fiddes, CA Hutchison, PM Slocombe, M. Smith, Nucleotide sequence of bacteriophage phi X174 DNA. In: Nature. Volume 265, 1977, pp. 687-695; PMID 870,828th

Autobiographical, survey