Corrections on few mistakes I may have done when describing the coronavirus.
By the way, I am not a Virologist like our own Sriyal Pieris who did most of the originals work. In my list of 20 objects to complete before I kick the bucket, a book on virology was one book. I collected big and small books on virology from 1965 (I was a A Level student) up to now.
I gave up this idea and changed my focus to Mosquitoes, Their Value in Our Ecology and not the 40 odd mosquitoes causing diseases out of the total 2500 to 3500 mosquito varities.
My Mistakes.
1. Confusion of its nanometer size to the number of amino acids per its nucleocapsid genome.
Sorry.
2. It is a very complicated virus.
3. There are 30,000 kilobases.
4. There are 10,000 proteins.
5. It is a spherical protein of the size of 100 nanometers and may go up to 200 nanomters.
I got the nanometer size of the protein also wrong by 100 to 300.
6. Full description of the structure and genome is below.
7. Genome size is 24 to 36 kilobases.
Total Amino Acids of the genome is about 8 to 12. I am vindicated here since the number of amino acids are small enough, so that a Primer can be formed in the laboratory to be linked to the so called Gain in Function Genome for rapid duplication.
This is the part Anthony Fauci played with Chinese counterparts with lot of exchange of money.
On that ground alone he should be sent to prison. Invoking and presumption of His Rights to be silent is not valid here in my opinion.
The damage he has done to science is beside the point of his defense.
Coronavirus Morphology
Coronaviruses are large pleomorphic spherical particles with bulbous surface projections.
The diameter of the virus particles is around 120 nm.
The envelope of the virus in electron micrographs appears as a distinct pair of electron dense shells.
The
viral envelope consists of a lipid bilayer where the membrane (M),
envelope (E) and spike (S) structural proteins are anchored.
A subset
of coronaviruses (specifically the members of Betacoronavirus subgroup
A) also have a shorter spike-like surface protein called hemagglutinin
esterase (HE).
Inside the envelope, there is the nucleocapsid, which is formed from multiple copies of the nucleocapsid (N) protein, which are bound to the positive-sense single-stranded RNA genome in a continuous beads-on-a-string type conformation.
The genome size for
coronaviruses ranges from approximately 27 to 34 kilobases.
The lipid bilayer envelope, membrane proteins, and nucleocapsid protect the virus when it is outside the host cell.
Coronavirus Replication
Infection
begins when the virus enters the host organism and the spike protein
attaches to its complementary host cell receptor. After attachment, a
protease of the host cell cleaves and activates the receptor-attached
spike protein.
Depending on the host cell protease available, cleavage and activation allows cell entry through endocytosis or direct fusion of the viral envelop with the host membrane.
On entry into the host cell, the virus particle is uncoated, and its genome enters the cell cytoplasm.
The
coronavirus RNA genome has a 5′ methylated cap and a 3′ polyadenylated
tail, which allows the RNA to attach to the host cell's ribosome for
translation.
The host ribosome translates the initial overlapping open reading frame of the virus genome and forms a long polyprotein.
The polyprotein has its own proteases which cleave the polyprotein into multiple nonstructural proteins.
A number of the nonstructural proteins coalesce to form a multi-protein replicase-transcriptase complex (RTC).
The main replicase-transcriptase protein is the RNA-dependent RNA polymerase (RdRp).
It
is directly involved in the replication and transcription of RNA from
an RNA strand.
The other nonstructural proteins in the complex assist in the replication and transcription process.
The exoribonuclease non-structural protein for instance provides extra fidelity to replication by providing a proofreading function which the RNA-dependent RNA polymerase lacks.
One of the main functions of the complex is to
replicate the viral genome.
RdRp directly mediates the synthesis of negative-sense genomic RNA from the positive-sense genomic RNA.
This is followed by the replication of positive-sense genomic RNA from the negative-sense genomic RNA.
The other important function of the
complex is to transcribe the viral genome.
RdRp directly mediates the
synthesis of negative-sense subgenomic RNA molecules from the
positive-sense genomic RNA. This is followed by the transcription of
these negative-sense subgenomic RNA molecules to their corresponding
positive-sense mRNAs.
The replicated positive-sense genomic RNA becomes the genome of the progeny viruses.
The
mRNAs are gene transcripts of the last third of the virus genome after
the initial overlapping reading frame.
These mRNAs are translated by the host's ribosomes into the structural proteins and a number of accessory proteins.
RNA translation occurs inside the endoplasmic reticulum.
The viral structural proteins S, E, and M move along the secretory pathway into the Golgi intermediate compartment.
There, the M proteins direct most protein-protein interactions required for assembly of viruses following its binding to the nucleocapsid.
Progeny viruses are then released from the host cell by exocytosis through secretory vesicles.
