Lecture 3: Protein Regulation, Structure, and Function

Question 1

Define the primary structure of a protein

Answer 1

• the sequence of amino acids
• are linked by non-covalent bonds
• the amino acid used in primary structure defines how the protein will fold

Question 2

What is folding?

Answer 2

• Force that occurs so hydrophobic regions stay on the inside of the protein
• driven by hydrophobic interactions
• can occur after translation or as translation is occurring (co-translational)
• influenced by neighboring residues

Question 3

What are the roles of chaperones

Answer 3

• prevent inappropriate interactions with other cellular components
• helps proteins achieve their shape
• work by binding the hydrophobic segments of proteins

Question 4

Define secondary structures

Answer 4

• Folding patterns to maximize the number of H-bonds w/ neighbouring amino aicds
• two common types: alpha helix and beta plated

Question 5

Define alpha helixs

Answer 5

Alpha helix
- H-bond w/ carboxyl to amine group
- b/w every 4th amino acid
- cylindrical twisting spiral
- can be counter clockwise or clokcwise
- can have a coiled-coil structure (2 helixes wrapped around each other) (driven by amino acid interactions)

Question 6

Define beta plated sheets

Answer 6

• starts from N-terminal to C-terminal
• can be parallel or anti-parallel

Question 7

Define tertiary structures

Answer 7

• Confirmation of entire protein
• Consists of domains that come together
• two types, Fibrous or Globular

Question 8

Define Fibrous and Globular shapes

Answer 8

Fibrous
- not as common
- very strong
- contribute to structure
- are long
Globular
- compact shape
- common
- can combine to form a longer shape

Question 9

Define Quaternary strucutres

Answer 9

• Linking of multiple proteins to from large complexes with multiple subunits
• relies on interactions b/w r groups
  -can have same subunits (homo) or 2 different subunits (hetero)

Question 10

what are ligands

Answer 10

• Ligands must fit precisely into a binding site
• Relies on non covalent bonds
• if ligand does not fit properly nothing will happen

Question 11

What are allosteric enzymes

Answer 11

enzymes that can inhibit or activate at different sites than the substrate binding site

Question 12

what is feedback inhibition

Answer 12

the products form at the end of a metabolic pathway inhibits the earlier enzymes that make it

Question 13

What are kinases

Answer 13

enzymes that adds phosphates

Question 14

what are phosphatases

Answer 14

enzymes that remove phosphate

Question 15

what are signaling cascades

Answer 15

reactions that occur in response to a stimulus