Diabetes

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Diabetes

• Revision of protein structure and the importance
  of genetic engineering in the control of diabetes

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Some diabetes sufferers control their blood
glucose levels by regular insulin injections.
This means that they must test for blood
glucose levels on a regular basis. The injection
must be taken 30 mins before a meal twice daily.
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Insulin is a hormone. It is made of protein and
is involved in the regulation of glucose levels
in the blood
The primary sequence
Notice amino acids are represented by three
letters lower case.
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The secondary structure. The alpha and beta
chains chain contains helical forms. This is
caused by hydrogen bonding between R groups on
the amino acids.
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The tertiary structure causes the formation of a
monomer.
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The quaternary structure involves the interaction
of monomers to form hexamers.  
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Ribbon model of the hexamer unit
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Insulin is injected as a hexamer as the monomers
only exist at low concentrations making the
volume to large to be injected
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The insulin is released as a hexamer, which must
be broken down to form monomers. Injected insulin
is in the form of hexamers and it takes half an
hour for the hexamers to form monomers and get
into the blood stream. The dose contains two
forms of insulin one a slow release and one a
fast release form. Hexamers have to be injected
as they exist in only very low concentrations.
They naturally form hexamers at high
concentrations. To inject the monomers at a low
enough concentration at the right amount would
involve too larger a volume
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Can genetic engineering come the the rescue?
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Producing insulin by genetic engineering
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Modifying the amino acid sequence could stop the
hexamers from forming by altering the
intermolecular forces of attraction to prevent
clumping
Using computer modelling and computer graphics,
it has been found that swapping the beta chain
9th amino acid (ser) with asp stops the clumping
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How can we change one residue?
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Consideration of insulin has allowed us to revise
structure of proteins and see how genetic
engineering has been used to modify a protein to
enhance its performance in a medical context.