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What is the result of a sequence of amino acids that has been disrupted; therefore causing an abnormal sequence?
Abnormal sequence of amino acids specified for a particular protein results in misfolding of that protein, which in turn causes impairment of normal functioning.
What are examples of secondary Structures of proteins and what type of bonds are used?
Both are stabilized by extensive hydrogen bonding
between the peptide bond carbonyl oxygens
and amide hydrogens
that make up the polypeptide backbone.
Hydrogen bonding can also occur between two different chains
What are the characteristics of the alpha helix?
- - Possesses a "right hand turn"
- - Each turn contains 3.6 amino acids
What is the amino acid that interrupts the alpha helix and how?
Proline produces a "kink" in the a-helix because it's structure is incompatible with the right hand spiral of the a-helix
What is the characteristic feature of Beta Sheets
They have a pleated appearance.
What is the structure of globular proteins?
What are the two different amino acids that must be in the structure?
Nearly 1/3 of the amino acid residues are in turns or loops where the polypeptide chain reverses direction.
The structure involves 4 amino acids, one of which must be proline or glycine.
Serum albumin is what type of protein and what level of structure?
Mostly alpha helices, tertiary structure
Collagenase is what level of protein structure and what kind of protein?
Mostly Beta strands, tertiary structure.
Thymidylate synthase is what kind and level of protein structure?
Mixed alpha helices and Beta strands, tertiary structure.
What type of bonds stabilize tertiary structures?
- Disulfide bonds
- Hydrogen bonds
- Ionic Bonds
What determines the shape of secondary, tertiary functional protein?
Interactions between the side chains of amino acids determines how a polypeptide chain folds into the intricate three-dimensional shape.
Characteristics of protein Domains?
Folding of peptide chains within a domain is INDEPENDENT of folding in other domains
Bovine spongiform encephalopathy, Amyloidoses and Alzheimer disease are the result of what?
Protein misfolding. For example, association of infected molecules change the folding from the intended to alpha helix to (misfolding) beta sheets.
What are characteristics of a Quaternary Structure?
Made by 2 or more polypeptide chains (subunits, or tertiary structures).
- These subunits are interact by
- Hydrogen bonds
- Ionic bonds
How do the subunits of a Quaternary structure interact?
Examples of this level of structure
Either cooperatively or independently
- Ex: - human hemoglobin
- - protein kinase
What are conjugated proteins?
These are proteins that contain permanently associated chemical components in addtion to amino acids
What is the range in number of Amino Acids in the chart he presented of proteins with quaternary structure?
Ranges from 972 to 5,628 amino acids
What happens when proteins denature?
Unfolding and disorganization of the proteins secondary and tertiary structures, which are not accompanied by hydrolysis of peptide bonds
What are possible denaturing factors?
- Strong acids or bases
- Organic solvents
- Ions of heavy metals such as lead, mecury
Why do denatured proteins precipitate out of solutions?
Because they are often insoluble