explains about protein structures

1. LEVELS OF PROTEIN
STRUCTURES
Presented by AMINA KHAN
MS CHEMISTRY
SA-CIRBS INTERNATIONAL ISLAMIC
UNIVERSITY ISLAMABAD

2. PROTEINS
Polymers consisting of amino acids
linked by covalent peptide bonds
 Many different conformations (three-
dimensional structures) are possible
for proteins
 Proteins are complex

3. FORMATION OF PEPTIDE BOND
A peptide bond is a chemical bond formed between two molecules
when the carboxyl group of one molecule reacts with the amino group
of the other molecule, releasing a molecule of water (H2O). This is a
dehydration synthesis reaction and usually occurs between amino
acids.

4. LEVELS OF PROTEIN STRUCTURES:
Four levels of protein structures are:
a. Primary structure of protein
b. Secondary structure of protein
c. Tertiary structure of protein
d. Quaternary structure of protein

5. PRIMARY STRUCTURE OF PROTEIN:
The primary structure of a protein is
the sequence of amino acids in the
polypeptide chain.
The primary structure is held
together by peptide bonds that are
made during the process
of protein biosynthesis.
The primary structure is the one-
dimensional

6. Importance of primary structure
One of the most striking demonstrations of the importance of
primary structure is found in the hemoglobin associated with
sickle-cell anemia.
 These drastic consequences stem from a change in one amino
acid residue in the sequence of the primary structure
The sickled cells tend to become trapped in small blood vessels,
cutting off circulation and thereby causing organ damage

7. SECONDARY STRUCTURE OF PROTEIN
Secondary structure is the arrangement
in space of the atoms in the peptide
backbone.
It is three-dimensional aspects of a
single polypeptide chain
Classification in types:
The a-helix and b-pleated sheet
arrangements are two different types of
secondary structure

8. TERTIARY STRUCTURE OF
PROTEINS:
Tertiary structure includes the
three-dimensional arrangement
of all the atoms in the protein,
including those in the side
chains and in any prosthetic
groups (groups of atoms other
than amino acids).

9. QUATERNARY STRUCTURE OF PROTEIN
A protein consist of multiple polypeptide chains called subunits.
The arrangement of subunits(multiple polypeptide chains) with
respect to one another is the quaternary structure.
Interaction between subunits is mediated by non covalent
interactions, such as hydrogen bonds, electrostatic attractions,
and hydrophobic interactions.

10. Forces in protein structure: