Word: amino
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Dates: during 1970-1979
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When he started his work, Ungar had only the vaguest suspicions about the chemistry involved in this transfer of fear. But after repeated experimentation, he concluded that the message was coded in amino acid chains called peptides, which are small proteins. Finally, he narrowed the search to a single peptide-consisting of a sequence of 15 amino acids-that he named scotophobin, from the Greek words for dark and fear. To check his conclusion, Ungar asked Wolfgang Parr, a University of Houston chemist, to duplicate scotophobin using only off-the-shelf chemicals. The synthetic variety differed slightly from the natural...
That evidence was in the form of 17 different amino acids found in the meteorite and identified by a team led by Ceylonese-born Cyril Ponnamperuma, 47. Significantly, half a dozen of those amino acids are among the 20 or so that are the building blocks of proteins-and thus of all terrestrial organisms. Convinced of the discovery's importance, the NASA team boldly asserted that it is "probably the first conclusive proof-of extraterrestrial chemical evolution...
Mirror Image. The NASA scientists are not the first to report finding amino acids in meteorites, which are believed to be fragments from the thousands of asteroids that circle the sun between the orbits of Mars and Jupiter. But previous claims have invariably been discredited because the amino acids were suspected to be of terrestrial origin; they could easily have contaminated the meteorites during or after their plunge through the earth's atmosphere. Even Ponnamperuma, a highly respected exobiologist (extraterrestrial biologist) at NASA's Ames Research Center in California, admits that only a thumbprint on a beaker could...
Besides the various amino acids, Ponnamperuma's team detected a greater proportion of carbon 13 than would be present in earthly organic matter. It also found a mixture of hydrocarbons curiously like that produced in experiments simulating the conditions of a primitive planetary atmosphere. The most compelling evidence was the nature of the amino acids themselves. Ever since Louis Pasteur's day, chemists have known that the atoms of organic compounds like amino acids can be assembled in two ways-one a mirror image of the other. Yet except for those made artificially, most amino-acid molecules found...
...Within a few years the prospects are fairly good for discovering amino acids-if they are there," Ball said...