TITLE: From Proteins to Protolife
AUTHOR: LIPKIN, RICHARD
JOURNAL: Science News
CITATION: July 23, 1994, 146: 58-59.
YEAR: 1994
PUB TYPE: Article
IDENTIFIERS: ORIGIN OF LIFE; PROTOCELLS; THERMAL PROTEINS; MICROSPHERES;
AMINO ACIDS; PROTEINS; EVOLUTION/ORIGIN; PRIMORDIAL LIFE
ABSTRACT: The theory that life evolved from lower unicellular
organisms to more complex ones is a plausible premise in
science. Continuing advances in biochemistry and chemistry
show that organisms are chemical machines driven by their
molecular makeup. Following this premise further, living
cells developed from nonliving molecules, and the origin of
life may not be as random as many assumed. Scientists at the
University of Chicago more than 40 yr. ago showed that amino
acids can form from complex molecules in primordial
conditions of heating, cooling, and electrification. Other
scientists went on to show that amino acids can form into
simple proteins under primordial conditions. Proteins are the
core structure of living cells. The proteins can go on to
produce small, cell-like objects called microspheres.
Microspheres do not have the internal structure that run
living cells. They do, however, bear a resemblance to
microfossils of Precambrian rocks. Microspheres also join
together and electrically signal to each other when
stimulated by light. Scientists struggle with the question
whether or not they played a role in the development of life.
Sidney W. Fox, one of the pioneer scientists in this area,
believes they did play a part. He believes that these thermal
proteins assembled into microspheres and then protocells,
leading to the evolution of nucleic acids.
The idea challenges conventional thinking that nucleic
acids needed to exist before the arrival of any form of
living cell. Thermal proteins compose the protocell membrane
that acts in many ways like a living cell membrane. Thermal
proteins may have been the first step in evolution. The cell-
like structures could be the forebears of organisms like
bacteria, archaea, and eucharya. If the theory proves correct
and life evolved from a highly determined chemical sequence,
life is likely to occur elsewhere in the universe.