Structure of Proteins Flashcards
Four Types of Structures of proteins
– Primary Structure
– Secondary Structure
– Tertiary Structure
– Quaternary
is the order in which amino
acids are linked together in a protein by peptide bonds;
Primary Structure
Primary Structure is the order in which amino acids are linked together in a protein by
peptide bonds
the backbone of the protein molecule
peptide bonds
Every protein has its own unique
amino acid
sequence
sequenced and
determined the primary structure for the first
protein - Insulin
Frederick Sanger (1953)
primary structure for the first
protein
Insulin
The various amino acids present in a protein, whose order is the primary structure of the protein, are linked to each other by
peptide linkages
Primary Structure of Proteins have four types of structures which are
– Primary Structure
– Secondary Structure
– Tertiary Structure
– Quaternary
The only bond responsible for
the 2o structure of proteins is
H- bonding between peptide bonds
one
peptide group and the –N – H of
another peptide linkage farther
along the backbone.
–C = O
The two most common types of Secondary Structure of Proteins
alpha-helix (α-helix) and
the
beta-pleated sheet (β-pleated sheet).
A single protein chain adopts a shape that
resembles a coiled spring (helix):
Alpha-helix (α-helix)
H-bonding between amino acids with in
the same chain –intramolecular H-
bonding
Alpha-helix (α-helix)
H-bonding between amino acids with in
the same chain
–intramolecular H- bonding
Coiled helical spring
Alpha-helix (α-helix)
R-groups stay outside of the helix – not
enough room for them to stay inside
Alpha-helix (α-helix)
The helix is so tightly wound that the
space in the center is too small for solvent
molecules to enter
Alpha-helix (α-helix)
is so tightly wound that the
space in the center is too small for solvent
molecules to enter
helix
Completely extended protein chain
segments in same or different
molecules governed by intermolecular
or intramolecular H-bonding
Beta-Pleated Sheets
Completely extended protein chain
segments in same or different
molecules governed by
intermolecular or intramolecular H-bonding
H-bonding between different parts of a single chain
intramolecular H- bonding
H-bonding between different parts of a
single chain – intramolecular H- bonding
Beta-Pleated Sheets
Side chains below or above the axis
Beta-Pleated Sheets
