Now before I go further and talk about processing
of other RNAs, I wanna stop for a moment
and talk about another function of RNAs; because, they are
related to a processing of transfer RNAs that I will talk about.
And these are the RNAs that
are catalytic in nature.
These RNAs actually catalyze chemical reactions
that the RNA equivalent of enzymes.
We call them ribozymes; because,
they catalyze reactions.
Now ribozymes play roles in
ribosomes and I bring that up
up here; because, it's pretty
easy to confuse those two terms.
A ribozyme catalyzes a reaction.
A ribosome is a big structure that
makes peptide bonds and proteins.
Ribosomes contain ribozymes.
Okay. So we can see that in
the figure that's shown here,
on the right, we see a ribosome and we have seen
this figure in another presentation that I have made.
In this reaction what's happening is
individual amino acids are being
joined, as we can see here,
in formation of peptide bonds.
And during the formation of those
peptide bonds, one of the ribosomal RNAs
specifically the 23S ribosomal RNA in the
case of a prokaryotic system
is making the bond between
the adjacent amino acids.
So that peptide bond formation
is happening as a result
of action of a ribozyme
within a ribosome. Okay.
So there are other ribozymes
that play roles in processing
of individual transfer RNAs. So let
me show you one of these.
This is a ribozyme known as RNase P.
RNase P plays an important function in the
final processing that's done on a transfer RNA.
Now it's pretty simple but nonetheless
it's a catalysis that occurs.
On the screen you can see the transfer RNA
and at the 5 prime end you can see a black
line sort of looped off on the side
that 5 prime end has to be processed. It has
to have that little piece removed; because,
without the removal, the transfer RNA will not function.
That piece is removed by RNase P.
So in addition to the many functions that
RNAs perform in the process of translation,
as you can see, they also perform functions
of catalysis and in some cases
those catalytic function run other
RNAs, an amazing group of molecules.
Now that's structure removed by RNase P
is simply lost. It's not very long
but it's long enough that it actually would stop the
translation process from happening if it were not removed.