Page 94 - The Miracle of Protein

92 THE MIRACLE OF PROTEIN

The number of ribosomes in a cell can be as many as a mil-
lion or more. This machine that translates RNA into a protein,
is made up of two large proteins and subunits, including a com-
bination of RNAs as well as hundreds of different cofactors. 23
Research on this nano molecule, which fascinates the scientists

with its details and features, is still underway.

Striking Speed of Transfer RNA in the

Ribosome
Experiments showed the ribosome can read 20 codons in

24
only 1 second. When we look at what the word ‘reading’
means in this process, we see that multiple processes take place
at the same time in a mind-blowing fashion. The raw material
that comes with the transfer RNA is selected correctly, taken in-
side, for codon-anticodon matching, the incoming amino acid

is added to the forming amino acid chain through peptide
bonds, and the tRNA that has done its duty exits. Since there
are three tRNAs currently inside the ribosome at one time, all
these processes must take place simultaneously without flaws
or interruptions. According to research published in Proceed-

ings of National Academy of Sciences in 2005, the time that pass-
es during the first stage, which is tRNA entering the ribosome
and ribosome checking to insure it is the right tRNA, is only 1,6
ns (1 nano second= 1/1.000.000.000 sec), while the second stage
which is the tRNA being moved to the peptidyl transferase area

takes only 0.292 ns.
The third stage from the time the amino acid is recognized
takes only 0.65 ns and the final stage, the separation of the