Download Protein Structures

Protein Structures
Explanation of
Protein Structures
Check out this link for more detail.
Rules to remember...
The sequence of the nucleotide determines the amino acid.
The amino acid sequence determines the protein shape.
The protein shape determines it function.
Primary Protein
Structure
Primary
Primary protein structures refer to the order in which amino acids link
together. Proteins combine to form a chain of amino acids.
The amino acids include an alpha carbon, which is bonded to a Hydrogen atom,
a carboxyl group and an amino group.
Amino acid sequences of a protein are determined by the information found
within the cellular genetic code.
The order of amino acids within the polypeptide chain is completely unique,
and is specifically linked to a protein.
When amino acids are changed within a sequence, a gene mutation occurs, which
often results in a protein that is non-functioning.
Secondary
Secondary protein structures occur when polypeptide chains
coil or fold, giving them a 3D shape.
Alpha(α)Helix structures resemble a coiled spring, and
result from hydrogen bonding within the peptide chain.
Beta Pleated structures seem to be folded, or pleated and
form when hydrogen bonds between adjacent polypeptide
units
Check out this link to learn more about secondary protein structures.
Tertiary Protein
Structure
Tertiary
Tertiary protein structures deal with the 3D shape of a polypeptide chain.
There are multiple bonds/forces that contribute to the protein’s ability to remain in
tact.
Hydrophobic interactions often play a key role in maintaining a protein’s shape. “R”
groups in amino acids are either hydrophobic or hydrophilic and will seek aquatic or
non-aquatic environments accordingly, which determines their location within the
protein.
Hydrogen bonds facilitate stabilization within the proteins based on the shape
established by the hydrophobic interactions.
Ionic bonding causes folding between positively and negatively charged R groups.
Check out this link to learn more about tertiary protein structures.
Quaternary Structure
Quaternary
Quaternary structures deal with the structures that between
multiple polypeptide chains.
Each chain is referred to as a subunit.
Structures may consist of multiple polypeptide chains that may either
be the same subunit, or different subunits.
Click this link to learn more about quaternary protein structures.
Why do they change
structures?
What can cause a protein structure to change?
Changes in pH
Changes in salt concentration
Changes in temperature
Presence of reducing agents
Where do you find
these structures?
How has environmental changes impacted our
need for different types of proteins?