Download Protein Structure

Protein
Structure
Primary Structure
 The
primary structure is the sequence of
amino acids, which is different for each
protein.
Primary Structure
 The
primary structure is the sequence of
amino acids, which is different for each
protein.
 The sequence determines the properties
of the protein.
Primary Structure
 The
primary structure is the sequence of
amino acids, which is different for each
protein.
 The sequence determines the properties
of the protein.
 The info for the sequence of amino acids
in a polypeptide chain is stored in a gene.
Primary Structure
 The
primary structure is the sequence of
amino acids, which is different for each
protein.
 The sequence determines the properties
of the protein.
 The info for the sequence of amino acids
in a polypeptide chain is stored in a gene.
 A gene can be defined as ‘the length of
DNA that codes for a polypeptide’
Primary Structure
 When
a mutation occurs in a gene, the
mutation usually results in an altered
protein – resulting in either a nonfunctional protein or do nothing at all.
Primary Structure
 When
a mutation occurs in a gene, the
mutation usually results in an altered
protein – resulting in either a nonfunctional protein or do nothing at all.
 Human proteins are made of 20 amino
acids.
Primary Structure
 When
a mutation occurs in a gene, the
mutation usually results in an altered
protein – resulting in either a nonfunctional protein or do nothing at all.
 Human proteins are made of 20 amino
acids.
 The number of possible different
sequences of the 20 amino acids is vast.
Secondary structure
 The
primary structure is bent/twisted to
form a helix or pleated sheet.
Secondary structure
 The
primary structure is bent/twisted to
form a helix or pleated sheet.
 Pleated sheet – sections of polypeptide
chains run side by side.
Secondary structure
 The
primary structure is bent/twisted to
form a helix or pleated sheet.
 Pleated sheet – sections of polypeptide
chains run side by side.
 The shapes are held in place by hydrogen
bonding between certain amino acids.
Tertiary Structure
 Globular
proteins are further bent to form
a complex shape.
Tertiary Structure
 Globular
proteins are further bent to form
a complex shape.
 This shape is both maintained by both
hydrogen and disulfur bonding between
certain amino acids.
Tertiary Structure
 Globular
proteins are further bent to form
a complex shape.
 This shape is both maintained by both
hydrogen and disulfur bonding between
certain amino acids.
Quartenary Structure
 Some
globular proteins are made of two
or more polypeptide chains held loosely
together.
Quartenary Structure
 Some
globular proteins are made of two
or more polypeptide chains held loosely
together.
 Eg – haemoglobin has four polypeptide
chains
Chemical Activity
 Although
globular proteins are large, their
chemical activity resides in a small part of
the molecule – the active site in enzymes.
Chemical Activity
 Although
globular proteins are large, their
chemical activity resides in a small part of
the molecule – the active sit in enzymes.
 The bonds maintaining the shape are
weak, so temperature can denature the
enzyme (lose it’s chemical/biological
function)
Chemical Activity
 Although
globular proteins are large, their
chemical activity resides in a small part of
the molecule – the active sit in enzymes.
 The bonds maintaining the shape are
weak, so temperature can denature the
enzyme (lose it’s chemical/biological
function)
 Enzymes are catalysts for chemical
reactions of life – they temporarily
combine with substances (the substrate),
forming an enzyme-substrate complex.
Chemical Activity
 This
bonding occurs at the active site –
slightly changing the shape to fit the
substrate.
Chemical Activity
 This
bonding occurs at the active site –
slightly changing the shape to fit the
substrate.
 This is possible because of the weak
bonds.
Chemical Activity
 This
bonding occurs at the active site –
slightly changing the shape to fit the
substrate.
 This is possible because of the weak
bonds.
 If an enzyme loses it’s shape because of
denaturing, or through a mutation in the
amino acid sequences, the active site
can be lost so the enzyme can no longer
catalyse the reaction.
Chemical Activity