Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Protein Structure
Protein Structure is described on four different levels; primary structure,
secondary structure, tertiary structure and quaternary structure
...

A conjugated protein is a protein to which a non-protein proportion is
attached
...
For example a conjugated protein would be
a glycoprotein, thats prosthetic group is carbohydrates
...
It is mechanically durable and unreactive which makes it an ideal
protein in vertebrates that take a lot of wear and tear to the areas that use
keratin (such as nails and hair)
...

The primary structure of keratin has three domains; the amino-terminal
head, central rod domain and the carboxyl-terminal tail
...
This
means that keratin is a sulphur-rich
...

Keratin has an alpha-helical structure
...
This allows for the whole keratin molecule
to be more compact
...
The
tertiary structure for keratin would be that its polypeptide chains are held
together by disulphide bridges
...

The quaternary structure of a protein describes the way in which protein
molecules are fitted together to form functional structures
...

Dimers are then arranged in a way to form a protofilament, these
protofilamets then dimerize to form protofibrils
...
This huge quaternary structure then goes
through one last stage in that the microfibrils then associate to form
macrofibrils
...
This makes it one of the most
abundant protein in most vertebrates
...
Collagen has a left-handed, alpha helical secondary structure
...
The alpha-helix is cross
linked by hydrogen bonds in order to hold the shape of the protein in place
...

The quaternary structure of collagen is very complex and this gives
collagen extreme strength
...
These three polypeptides wrap around one another to
form a right-handed triple helix that is formed by the regular assurance of
glycine in the primary structure of the protein
...

The primary structure of fibroin contains mostly glycine and alanine; due to
the presence of glycine, it allows for the tight packing of the molecule
...
These sheets are further cross linked in
parallel by hydrogen bonds to create the tertiary structure of the protein
...

The quaternary structure of fibroin is the stacking of the beta pleated
sheets to create a functional structure
...
It comprises of four polypeptide
chains around an iron containing haem group that acts as a prosthetic
group (conjugated protein)
...

The tertiary structure is that in each polypeptide chain, it is folded into a
precise shape - an important factor in its ability to carry oxygen
...

The quaternary structure of haemoglobin is in which all four of the
polypeptides are linked together to form an almost spherical molecule
...
Each Fe2+ ion can combine with a single oxygen molecule
(O2), making a total of four O2 molecules that can be carried by a single
haemoglobin molecule in humans
...
ccunix
...
edu
...
pdf
...
wiley
...
html
...
Stephenson



---