40 Self and the Phenomenon of Life
b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity “9x6”base-pairing, producing a 3-dimensional configuration unique for
each RNA molecule. The ability to form a unique conformation is
a prerequisite for enzyme catalysis.
(3) Many extant enzyme cofactors (coenzymes) are fragments of RNA
and are suspected to be vestiges (molecular “fossils”) of ances-
tral ribozymes. Coenzymes are small organic molecules that aid
in the function of protein enzymes. Many coenzymes are RNA
nucleotides or derivatives of these nucleotides. They include NAD
(nicotinamide adenine dinucleotide), FAD (Flavin adenine dinu-
cleotide), S-adenosylmethionine, coenzyme A, thiamine pyrophos-
phate, tetrahydrofolate, and pyridoxal phosphate. The implication
is that RNA played an enzymatic role in early metabolism.^23
(4) ATP (adenosine triphosphate), the universal energy carrier of a
cell, is a derivative of ribonucleotide.
(5) Cyclic AMP and cyclic GMP, both derivatives of ribonucleotides,
are important second messengers involved in intracellular signaling.
(6) Many ribonucleoside phosphates are used as intracellular activa-
tors for synthetic purposes: AMP, UMP, UDP, CMP, CDP, GMP,
and GDP. (The abbreviations, respectively, are: adenosine mono-
phosphate, uridine monophosphate, uridine diphosphate, cytidine
monophosphate, cytidine diphosphate, guanosine monophosphate,
and guanosine diphosphate.)
(7) In today’s ribosome, the formation of peptide bonds of a protein is
the work of a ribozyme.
(8) In the laboratory, random-sequenced RNA can be “crafted” to turn
into ribozymes under man-made selective pressure. These man-
made ribozymes can carry out specific catalytic functions (though
less efficiently), including template-directed RNA replication, RNA
aminoacylation, nucleotide synthesis, and peptide bond formation.^24
(9) The clay montmorillonite has been found to be able to catalyze the
formation of short RNA chains by polymerization of ribonucleotides.^25
(10) Using cyclic AMP and cyclic GMP as starting materials, polymers
(up to 25 nucleotides long) of adenylic and guanylic acids simulating