Peptides and Proteins Flashcards
What is Ehlers-Danlos Syndrome?
Defect in structure, production, or process of collagen or proteins interacting with collagen
Polypeptide chains are what?
Hint: shape
Planar
What are amino acids joined covalently by in a peptide chain?
Amide bonds
What are proteins also known as?
Polypeptides
Proteins have a _____ backbone of _____ different side chains protruding.
Repeating; 20
What is the order of chemical interactions that stabilizes a polypeptide?
Covalent bond > Disulfide bond > Salt bridge > Hydrogen bond > Van der waals
What happens during a secondary structure?
Polypeptides begin to fold
In a secondary structure, hydrogen bonding occurs every ____ amino acids.
4
What is the primary stabilizing feature for polypeptides in a secondary structure?
Hydrogen bonds
An alpha helix is a what kind of turn?
Right hand
Beta strand makes up what?
Beta sheets
A beta strand has alternating ____?
R groups
In an antiparallel BETA sheet, the adjacent B tuns in what direction?
Opposite
What groups connect each amino acid to a single amino acid on adjacent strands?
NH and CO groups
In a parallel BETA sheet, the adjacent b runs in what direction?
Same
In a BETA sheet, the side chains are located where?
Above and below the plane
In a tertiary structure, hydrophobic amino acids are found where?
On the inside
What are found on the protein surface of a tertiary structure?
Charged amino acids (hydrophilic amino acids)
Primary structures have what kind of backbone?
Linear
Secondary structures can consist of what?
Alpha helix, Beta sheets, reverse turns
What is involved inside a tertiary structure?
Hint: DHH
Disulfide bonds, hydrogen bonding, hydrophobic interactions
In protein denaturation, OIL is what?
Oxidation losing e-
In protein denaturation, RIG is what?
Reduction is gaining e-
What is B-mercaptoethanol?
- reducing agent that gains H
2. breaks disulfide bonds
8m urea is what kind of substance?
Harsh substance to denature
A native ribonuclease is what kind of structure?
Tertiary structure
A denatured reduced ribonuclease is what kind of structure?
Primary structure
In amino acid detection, Trp + Tyrosine = _____ when subjected to UV spec?
280nm
What is used for sequencing a peptide?
Edman degradation allows sequencing of a peptide
To study a primary structure, what can be used?
Mass spectroscopy, Proteases, Edman degradation
When studying a secondary structure, what can be used?
Circular dichroism (CD) spectroscopy
What does a CD spectroscopy do?
Depolarizes light substances depending on secondary structure
What can be used when studying a tertiary structure?
X-ray crystallography
What is the strongest type of chemical reaction that stabilizes a protein?
Covalent bond
What is the weakest type of chemical interaction that stabilizes a peptide?
Van der Waals interaction
What two things denature a ribonuclease?
8 M Urea and B-mercaptoethanol
Which procedure reveals the entire sequence of a peptide?
Edman degradation
With Edman degradation, what can be released without hydrolyzing the rest of the peptide?
Amino-terminal residue
Trypsin cleaves at the carboxyl end of what amino acids?
Arginine and lysine
Chymotrypsin cleaves at the carboxyl end of what amino acids?
Hint: PTT
Phenylalanine, tyrosine, tryptophan
CNBR cleaves at the end of what amino acid?
Methionine
Denaturation can cause the loss of what structures due to unfolding of the polypeptide chain?
Secondary, tertiary, and quaternary
