the same 20 amino acids
Directionality runs from
the N terminus to C
terminus
Proteins
Proteins are composed of amino acids.
They
perform by changing their three-dimensional shape (they change their
conformation).
Proteins are used for transport, signaling, and structure.
Proteins are also enzymes.
|
Proteins are derived from
the same 20 amino acids Directionality runs from
|
R groups vary in electric charge and their level of hydrophobicity.
This makes the 20 amino acids different and helps to determine conformation.
It also influences how a protein's transformation changes with its
environment
Bonding between two amino acids results in a variety of structures.
Condensation occurs when H2O is lost. |
The Zwitterionic Form: the condition of most amino acids  |
The
alpha helix has elasticity.
You can break the hydrogen bonds and the
helix will still come back together.
A beta sheet consists of hydrogen-bonding between parallel strands of amino acid chains.
This structure is very strong and compact.
Tertiary Structure of Proteins (their complete 3-D form):
In the tertiary structure the protein can become "inactive" or "active."
Denaturation occurs when the protein becomes inactive and loses its appropriate tertiary structure.
Renaturation occurs when the protein returns to its active form.
This is important because information is stored as a three dimensional structure.
H-bonding, ionic and covalent bonds, Van Der Waals, and
disulfide bridges (in cystine)
all contribute to a protein's structure.
Below is an image of a disulfide bridge that contributes to
protein structure.
