Upgrade to remove ads
WEEK 2, L2, Protein Structure
Terms in this set (36)
Hierarchy of protein structure
Primary structure is the
sequence of amino acids
Secondary Structure is made up of
simple, repetitive motifs- alpha helices and beta pleated sheet structures
the overall fold of a protein.
when several proteins fold together
Peptide bond (C-N bond) has a partial......character. Peptide bond length is ........C-N bond and C=N bond lengths. This gives the peptide bond.......which prevents much........around the peptide bond.
1. double bond
Phi (Φ) is the....
angle of rotation about the bond
between the alpha carbon atom and the nitrogen atom.
Psi (Ψ) is the....
the angle of rotation about the bond between the alpha carbon and carbonyl atom
Psi and Phi angles determine the.....
path of the polypeptide chain
Are all combinations of Psi and Phi angles possible?
No, many combinations are forbidden due to steric collisions between atoms.
Combinations of Psi and Phi angles can be shown on a two- dimensional
Areas of green on Ramachandran plot are?
are permitted areas where the protein can fold.
If we have a highly flexible polymer it will not fold into.......
The.........of the peptide bond and the restricted set of.........values..........the number of structures accessible to the........ to allow protein.........to take place
2. psi and phi
4. unfolded form
Secondary structure is when the protein folds into.......
1. alpha helices
2. beta pleated sheets
3. turns and loops
Alpha helix is a.......structure which arises from......
1. helical structure
2. hydrogen bonding between the NH backbone and CO groups.
Alpha helix properties
1. 3.6 residues (n) per turn
2. 5.4Å pitch (distance it rises along its axis/turn)
3. H-bonding arranged such that the the C=O bond of the nth residue bonds to the N-H group of the (n+4)th residue.
4. R groups all point outwards
5. In globular proteins around 11 residues long
When we look down the helix of the alpha helices the amino acid residues facing the outside of the protein are. in contact with........and are........., whilst those facing the inside are...........
Give examples of proteins rich in alpha helices
1. ferritin (used to store iron)- around 75% of all its amino acid residues are in alpha helices.
2. About 25% of all soluble proteins are composed of alpha helices connected by turns and loops.
Beta pleated sheet is a....structure composed of........
Beta pleated sheet properties
1. Made from at leats two polypeptide chains
2. Can be parallel or antiparallel
3. Have a rippled or pleated appearance
4. H bonding with C=O of one chain and to N-H of another chain.
5. In globular proteins around 15 residues long.
Give an example of a protein rich in beta pleated sheet
Fatty acid biding proteins
Reverse turn/hair pin turn/Beta turn IS
A means by which a protein can reverse the direction of the polypeptide chain. Done via the H bonding of C=O of residue i to an N-H group of residue i+3.
A reverse turn/hairpin turn/beta turn.....
stabilises abrupt changes in direction of the polypeptide chain.
1. lack a regular or periodic structure
2. are often rigid
3. lie on the surface of proteins and often participate in interactions between other proteins and molecules.
"super secondary" structure is composed of....
1. secondary structures which link together into many combinations.
The "super secondary" structures form as.........
mini domains (a section that can fold independently which has a particular functional or structural role in a protein )
Tertiary structure is....
The overall fold of the whole protein, which can be made up of any combination of alpha helices, beta pleated sheets and loops.
Example of an all alpha helix protein....
Characteristics of myoglobin
1. 153 amino acids long
2. binds to a heme prosthetic group
3. dimensions 45 x 35 x 25 Å
4. 70% of the main chain is folded into 8 a-helices, the rest form turns and loops.
Distribution of amino acids in myoglobin
1. Hydrophobic amino acids mainly clustered in centre
2. Hydrophilic amino acids (charged) mainly clustered on the surface.
Example of an all Beta pleated sheet protein...
Concanavalin A (ConA)- is a lectin (carbohydrate binding protein)
Characteristics of ConA
1. 14 beta strands in a ConA molecule.
Domain of a protein is a.......
1. a section that can fold independently which has a particular functional or structural role in a protein
2. Every protein has at leats one domain
1. when two or more polypeptide chains combine (aka multimer)
2. Two or more copies of the same protein combine=
3.Two or more different proteins combine=
Human haemoglobin composed of ....
two alpha and two beta subunits each bound to a heme group
THIS SET IS OFTEN IN FOLDERS WITH...
WEEK 2, L1, Amino Acids and Proteins
WEEK 3, L4, Protein Folding and Stability
WEEK 3, L5, Enzymes and Coenzymes
WEEK 4, L6, Atomic Structure
YOU MIGHT ALSO LIKE...
biochem unit 4
OTHER SETS BY THIS CREATOR
WEEK 3, L4b, DNA replication 2, Enzymes at the rep…
WEEK 3, L4a, DNA Replication 1
WEEK 2, L3c, Translation
WEEK 2, L3b, Roles of RNA in Translation
OTHER QUIZLET SETS
Hatchet - Test questions
Donaven Thomas - Chemistry Review Game P…
Financial Accounting 2