Download Macromolecule Scramble

Where are amino acids linked?
 In living cell Ribosomes!
 These reactions that occur on
the ribosomes are controlled
by ENZYMES (more on this
later)
How are polypeptides broken?
 Hydrolysis Reactions
 Naturally occurs in stomach and
small intestine
 Protein in food is hydrolyzed into
amino acids prior to being absorbed
by the blood
 Once in the blood, these AA can be
restructured into polypeptides and
then twisted and folded into
functioning PROTEINS the cells in
you body needs
Protein Structure
 Primary structure 1’
 Order of amino acids in a polypeptide chain
 Secondary structure 2’
 Polypeptide chain folds because of interactions between
amino acids
 HYDROGEN BONDING
 Tertiary Structure 3’
 Gives proteins 3-D shape
 VERY IMPORTANT to function of protein
 Beta pleated sheets and alpha helices fold based on
interactions between R-groups of a.a.
 Hydrogen bonds, polar/non-polar interactions, acid/base
interactions, disulfide bonds, van derWaals forces
 Quaternary Structure 4’
 the association of the polypeptide chains
 some proteins contain more than one polypeptide chain
 Each polypeptide chain in the protein is called a subunit
 Two or more subunits come together for a specific
function
 HEMOGLOBIN
 On Red blood cells
 Its shape allows RBCs to carry oxygen all around your body!
Practice Set 6
Primary Structure
 Sequence of AA in a long




polypeptide chain
AA= letters of alphabet
Sequence of AA= arrangement of
letters to make words
HUGE amount of different primary
structures
Changing ONE AA is polypeptide
chain GREATLY changes the
properties of the polypeptide chain
and PROTEIN
Secondary Structure
 The order of AA in
polypeptide chain determine
interactions between
functional groups of AA
 Functional groups interact via
HYDROGEN BONDS
 Attraction between oxygen
in the –CO end of one AA
and the hydrogen in the –
NH end of another AA
 H-bond easily broken
 Change pH and change
Temperature
 Three possible 2o structures
 Determined by order R-groups
 No particular arrangement
 Alpha helix
 Polypeptide chains that coil
tightly
 Beta pleated sheet
 Looser, straighter shape
created by hydrogen bonds
Tertiary Structure
 Secondary structure gets coiled and
folded
 Precise 3D shape
 Folding is determined by interactions
between R-groups
 Hydrogen bonds
 Tryptophan
 Arginine
 Asparigine
 Disulphide bonds
 Between 2 cystine molecules
 Ionic bonds
 b/t R groups containing amine and
carboxyl groups
 Hydrophobic interactions
 b/t R groups that are non-polar
(hydrophobic)
2 main types of tertiary structures
 Globular
 form ball-like structures where hydrophobic parts
are towards the centre and hydrophilic are towards
the edges
 Structure=water soluble
 Found in watery environments
o cells, tissue fluid, or in fluids being transported
(blood or phloem)
 metabolic roles
 Ex: enzymes in all organisms, plasma proteins and
antibodies in mammals
 Fibrous
 form long fibres
 mostly consist of repeated sequences of amino acids
which are insoluble in water
 usually have structural roles
 Ex.
 Collagen in bone and cartilage
 Keratin in fingernails and hair
Quaternary Structure
 Proteins are made up of multiple polypeptide
chains, sometimes with an inorganic
component (for example, a haem group in
haemoglogin)
 Prosthetic Group (inorganic component
of protein)
 These proteins will only be able to function if
all subunits are present
 Made by same bonds found in tertiary structure
 Interactions between R-groups
 Hydrogen bonds
 Tryptophan
 Arginine
 Asparigine
 Disulphide bonds
 Between 2 cystine molecules
 Ionic bonds
 b/t R groups containing amine and carboxyl groups
 Hydrophobic interactions
 b/t R groups that are non-polar (hydrophobic)