There
is a long list of Indians with significant contributions to Science but could never
win a Nobel Prize. On the sixtieth anniversary of Triple helix, an analysis of
the work of Biophysicist Dr. G N Ramachandran may throw some light on certain
setbacks of India even when blessed with richest human resources on earth.
Gopalasamudram Narayana
Iyer Ramachandran, popularly known among contemporaries as GNR, breathed
science. Pauling’s α-helix, Watson and Crick’s Double helix and Ramachandran’s
Triple helix are regarded as the most outstanding contributions in Structural
Biology. On noticing the brilliant and illustrious young GNR, the pioneer of
optics Sir C V Raman handpicked and mentored him at Indian Institute of
Science. With a strong foundation in complex mathematical theorems, GNR worked
on X-ray topography in Raman Lab which set the basics of crystallography. He
befriended Linus Pauling at Cambridge during his postdoctoral days, who brought
his attention towards the structure of collagen, the most abundant protein in
animals. When A L Mudaliar, the visionary Vice Chancellor of University of
Madras decided to start an experimental Physics division in Madras, Sir C V
Raman himself recommended GNR to head the team. At the young age of 29, GNR
joined as a Professor at the university and started his work on deciphering the
structure of collagen. In 1954, GNR and his postdoctoral research fellow
Gopinath Kartha published the first proposed structure of collagen elucidated
from X-ray diffraction patterns and physicochemical data. They proposed three
parallel left-handed polypeptide chains packed in a hexagonal array. Each helix
had 32 symmetry
and hence three residues per turn of the helix with every third residue being a
centrally-facing glycine. They reworked on the structure using fiber
diffraction patterns and published a more accurate structure in the August
issue of Nature in 1955. They proposed 3.3 residues per turn with each
of the three parallel left-handed helices coiled right handedly around a
central axis. This structure later became popular as the coiled coil structure
of “Madras Helix”.
In the November issue of Nature the same year, Francis H Crick
and Alexander Rich came up with a harsh criticism of the structure citing
steric constraints. “We believe this idea to be basically correct but the
actual structure suggested by them to be wrong”. The structure proposed by GNR
had two interchain hydrogen bonds. Crick and Rich pointed out that the hydrogen
bond angles were outside acceptable limits and the structure was too compact to
accommodate large constituent amino acids. The Cα – Cα contact originally
proposed by GNR was 3.3A where as the acceptable limit was 3.6A. They proposed
only one hydrogen bond for the structure to be stereochemically stable. The
criticism was healthily received by GNR. He came up with the blockbuster
Ramachandran plot in 1963 to visualize the backbone dihedral angles of amino
acids in protein structure to predict its stability and hence feasibility. He also
revised the collagen structure to propose the currently accepted 1.5 hydrogen
bonds-structure from the weak van der Waal’s forces of water in 1968. Was it
just half of a hydrogen bond or the 0.3A distance that made GNR lose
international acclaim and the Nobel itself?
The answer is of course no.
It was not a secret that after deciphering the structure of DNA, Crick and his
team were working on collagen structure to which GNR raised a huge competition.
Nature did not accept GNR’s complete
paper on collagen structure but only published a short letter. GNR’s colleague
Professor Balaram of Indian Institute of Science says that even that letter was
kept on hold for more than six months without publishing even though the
content was immensely pertinent. It cannot be ignored that at the same time
Crick’s criticism was published in a month. The controversies only strengthened
GNR and brought out the golden age of protein structures. The minimum nonbonded
distance between atoms and the feasible molecular structures became crisper in
limits and definition and of course paved way to the genesis of Ramachandran
Plot. But his contemporaries including Linus Pauling believe that the master
missed the prize because he was not as aggressive in life as he was in science.
Moreover, before the internet era, geographical location was a huge setback for
Indian scientists. GNR did not even enjoy his moment of victory as he received
the journal with his paper in print only months after Crick’s criticism came
since it took months for regular mails from west to reach India.
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