Everything about William Astbury totally explained
William Thomas Astbury FRS (Bill Astbury,
25 February,
1898 —
4 June,
1961) was an
English physicist and
molecular biologist who made pioneering X-ray diffraction studies of biological molecules. His work on
keratin provided the foundation for
Linus Pauling's discovery of the
alpha helix. He also studied the structure for
DNA in 1937 and made the first step in the elucidation of its structure.
Early life
Astbury was the fourth child of seven, born in
Longton, Stoke-on-Trent,
His
father, William Edwin Astbury, was a potter and provided comfortably for
his family. Astbury also had a younger brother, Norman, with whom he
shared a love of music.
Astbury might well have become a potter but, luckily, won a scholarship to
Longton High School, where his interests were shaped by the Headmaster and second master, both chemists. After becoming Head boy and winning the Duke
of Sutherland's Gold Medal, Astbury won the only local scholarship available and attended to
Jesus College, Cambridge.
After two terms at Cambridge, his studies were interrupted by service during the
First World War. A poor medical rating following appendectomy
resulted in his posting in 1917 to
Cork,
Ireland with
the
Royal Army Medical Corps. He later returned to Cambridge and
finished his last year with a specialization in
physics.
After graduating from Cambridge, Astbury worked with
William Bragg, first at
University College London and then, in 1923, at the
Davy-Faraday Laboratory at the
Royal Institution in
London. Fellow students included many eminent scientists, including
Kathleen Lonsdale and
J. D. Bernal and others. Astbury showed great enthusiasm for his
studies and published papers in "classic
crystallography, such as the
structure of
tartaric acid.
X-ray diffraction studies of fibrous proteins
In 1928, Astbury was given a lectureship at the
University of Leeds where he studied the properties of fibrous substances such as
keratin and
collagen with funding from the textile industry. (Wool is made of keratin.) These substances didn't produce sharp patterns of spots like crystals, but the patterns provided physical limits on any proposed structures.
In the early 1930s, Astbury showed that there were drastic changes in
the diffraction of moist wool or hair fibers as they're stretched
significantly (100%). The data suggested that the unstretched fibers
had a coiled molecular structure with a characteristic repeat of 5.1 Å
(=0.51 nm). Astbury proposed that (1) the unstretched protein molecules
formed a helix (which he called the α-form); and (2) the stretching
caused the helix to uncoil, forming an extended state (which he called the
β-form). Although incorrect in their details, Astbury's models were
correct in essence and correspond to modern elements of
secondary structure, the α-helix and the β-strand (Astbury's nomenclature
was kept), which were developed twenty years later by
Linus Pauling
and
Robert Corey in 1951.
Hans Neurath was the first to show
that Astbury's models couldn't be correct in detail, because they
involved clashes of atoms. Interestingly, Neurath's paper and Astbury's data
inspired
H. S. Taylor (1941,1942)
and
Maurice Huggins (1943) to
propose models of keratin that are very close to the modern α-helix.
In 1931, Astbury was also the first to propose that mainchain-mainchain
hydrogen bonds (for example, hydrogen bonds between the backbone amide
groups) contributed to stabilizing protein structures. His initial
insight was taken up enthusiastically by several researchers,
including
Linus Pauling.
Astbury's worked moved on to X-ray studies of many proteins (including
myosin,
epidermin and
fibrin) and he was able to deduce from the diffraction patterns that the molecules of these substances were coiled and folded.
In 1937
Torbjörn Caspersson of Sweden sent him well prepared samples of
DNA from calf thymus. The fact that DNA produced a diffraction pattern indicated that it also had a regular structure and it might be feasible to deduce it. Astbury reported that DNA's structure repeated every 2.7 nanometres and that the bases lay flat, stacked, 0.34 nanometres apart. At a symposium in 1938 at
Cold Spring Harbor, Astbury pointed out that the 0.34 nanometre spacing was the same as amino acids in polypeptide chains. (The currently accepted value for the spacing of the bases in B-form of DNA is 0.332 nm.)
In 1946 Astbury presented a paper at a symposium in
Cambridge in which he said: "Biosynthesis is supremely a question of fitting molecules or parts of molecules against another, and one of the great biological developments of our time is the realisation that probably the most fundamental interaction of all is that between the proteins and the nucleic acids." He also said that the spacing between the
nucleotides and the spacing of
amino acids in proteins "was not an arithmetical accident".
Astbury's was unable to propose the correct structure of DNA from his rudimentary data. However in 1952
Linus Pauling used Astbury's insufficient data to propose a structure for DNA, which was also incorrect. Nevetheless Astbury's insights led directly to the work of
Maurice Wilkins and
Rosalind Franklin and from there to the structure of DNA devised by
Francis Crick and
James D. Watson in 1953.
In later life he was given many awards and honorary degrees.
Personal qualities and history
Astbury was known for his unfailing
cheerfulness,
idealism,
imagination and
enthusiasm. He foresaw correctly the tremendous
impact of
molecular biology and transmitted his vision to his students,
"his euphoric evangelizing zeal transforming laboratory routine into a great adventure" (Bailey reference below). Astbury's enthusiasm may also account for an occasional lack of scientific caution observable in his work; Astbury could make speculative interpretations sound plausible.
Astbury was an excellent writer and lecturer; his works are characterized by
remarkable clarity and an easy-going, natural manner (which might require
considerable work on his part!). He also enjoyed music, playing both piano
and violin.
Astbury met Frances Gould when he was stationed in Cork, Ireland with the
Royal Army Medical Corps during
World War I. They married in 1922
and had a son Bill and a daughter.
Further Information
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