Ch 1.7 Proteins Flashcards
(25 cards)
What are examples that proteins do?
- transcription/translation, regulation, transport, structure, catalyst, signaling etc.
What are the 4 levels of proteins?
- Primary
- Secondary
- Tertiary
- Quaternary
What are the parts of an amino acid?
- alpha carbon
- R group
- amino group
- carboxyl group
What’s two amino acids together?
Amino acyl residue
What are 3 types of side chains in amino acids?
- Hydrophobic
- Hydrophilic polar
- hydrophilic charged
What is primary structure?
- liner sequence amino acids encoded by gene that was transcribed to mRNA
- the sequence will determine the folding and the function
Why are proteins flexible
- many bonds can rotate
Directionality proteins?
- N - C
- numbered 1 at N
What determines the structure in proteins?
The R group
What is the secondary structure?
- alpha helix ( forms h- bonds along the backbone)
- beta pleaded sheet ( H- bonds between areas peptide backbone)
What is tertiary structure?
- determines by non covalent interactions of R- group
- a and B folds up
- stabilized by side chain interactions (non- covalent and disulfide) and interactions side chain backbone
Quaternary structure?
2+ tertiary structure combined
Alpha vs Beta secondary structure ( 6 points)
Alpha: right hand coil, h bonds formed in chain, bonds between NH and CO, R-group orientated outside, can be single chain, 1 type
Beta: paper fan like structure, formed by linking 2+ beta by h bonds, bonds between neighboring NH CO, R both in and outside, can’t exist as single B strand, parallel, anti-parallel or mixed
Integral protein?
Through bilayer
Peripheral proteins?
And why can they be removed with salts?
On each side bilayer
Cuz salt disrupts covalent bonds
Where are the hydrophobic and hydrophilic R groups located in a protein?
Exceptions?
Hydrophobic inside ( not all inside hydrophobic)
Hydrophilic outside
Some exceptions like when phobic used ID- ID with other subunit in cellar
Interior hydrophilic can be used active site
What is the enzyme active site?
Where the reactants go
Then proteins folds up to bring active site amino acids together
What does a catalyst do?
Speed up the reaction without changing the thermodynamics
Transition state in enzyme reaction?
Intermediate state between area tans and products
What do enzymes do?
- Make tradition state more stable
- less activation energy
What are the catalyst steps?
- Initiation: enzyme binds substrate forming enzyme substance complex
- Transition state stabilization: makes it go to transition state
- Termination : reaction finishes and enzyme goes back normal
Confirmation change in enzyme réactions?
When a substrate binds to an enzyme the shape of the enzyme changes
Helps enzyme bind transition state better = more stable transition state
How are enzymes regulated?
Many allosterically: a molecules different from substrate binds somewhere other active site protein: trigger conformation change
What is denaturation and how do you do it?
- unfolding protien
- high temp, pH, sovelnts
Some can refile but some can’t
