Module 2 Flashcards

1
Q

Name the 4 levels of protein structure and their (very) basic definition.

A

Primary - sequence of amino acids
Secondary - repeating interactions of amino acids
Tertiary - arrangement of atoms in a subunit
Quaternary - arrangement of subunits

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2
Q

T or F: Fibrous proteins are more soluble than globular proteins.

A

False

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3
Q

What are the two common secondary protein structures?

A

alpha-helix and beta-pleated sheets

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4
Q

What bonds do the Φ and Ψ describe?

A

Φ - alpha-carbon and nitrogen bond
Ψ - alpha-carbon and carbon bond

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5
Q

T or F: Trans configuration for chain of amino acids have more steric hindrance; therefore, it is less stable.

A

False. Less; more stable

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6
Q

What are the two exceptions for the Ramachandran Plot?

A

Proline and Glycine

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7
Q

Its permissible range of Φ and Ψ covers a large area of the Ramachandran diagram. Which amino acid is described?

A

Glycine

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8
Q

It is the most conformationally restricted amino acid.

A

Proline

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9
Q

Pitch of alpha-helix.

A

5.4 Å

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10
Q

How many amino acids per turn in an alpha-helix structure.

A

3.6

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11
Q

This amino acid creates a bend, disrupting alpha-helix structures.

A

Proline

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12
Q

What are the three alpha-helix disruptions?

A
  1. Presence of proline
  2. Strong electrostatic repulsion - K and R
  3. Crowding or steric repulsion
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13
Q

In alpha-keratin, how much residue-units are repeated to form the structure?

A

Seven

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14
Q

Collagen

A
  • consists of three extended helical chains wrapped into a triple helix (superhelix)
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15
Q

Amino acid derivatives found in collagen.

A

Hydroxyproline and hydroxylysine

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16
Q

The smallest component of hair cortex, composed of four alpha-keratins twisted into a left-handed superhelix

A

Protofibril

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17
Q

Component of hair cortex

A

Cortex -> Macrofibril -> Microfibril -> Protofibril

18
Q

Type of beta-sheet in which the hydrogen-bonded chains extend in the same direction

A

Parallel sheet

19
Q

Describe antiparallel sheet.

A

Neighboring hydrogen-bonded chains run in opposite directions

20
Q

T or F: Parallel beta-sheets are less stable than antiparallel beta-sheets

A

True

21
Q

Describe the parallelism of fibroin.

A

Anti-parallel

22
Q

Which interactions hold the tertiary structure of proteins?

A
  • Hydrogen bonding:
    + between peptide groups
    + between side chains
  • Metal ion coordination
  • Disulfide bonds
  • Hydrophobic interactions
  • Ionic linkages
23
Q

Protein that is responsible for storing oxygen in muscles.

A

Myoglobin

24
Q

T or F: Hemoglobin is a quaternary tetrameric protein.

A

True

25
Q

What is the function of hemoglobin?

A

Transportation of oxygen

26
Q

Refers to the property of hemoglobin where if one heme group is bound with oxygen, it becomes easier for the next oxygen to bond.

A

Cooperative binding

27
Q

What are the compounds that lower the affinity of oxygen to hemoglobin?

A

H+
CO2
BPG (D-2,3-bisphosphoglycerate)

28
Q

What is the reagent used in Edman degradation?

A

PITC (phenyl isothiocynate)

29
Q

What is the Sanger’s reagent’s full name?

A

2,4-Dinitrofluorobenzene

30
Q

This analysis is done to identify amino acids.

A

Sanger Analysis

31
Q

It is an efficient way to identify the N-terminal amino acid

A

Edman degradation

32
Q

It cleaves internal peptide bonds

A

Endopeptidases

33
Q

It cleaves the scissile peptide bond flanked by the residues with specific side chain requirements

A

Protease

34
Q

It cleaves either N or C terminal

A

Exopeptidase

35
Q

Which amino acids do trypsin cleave?

A

R Arginine
K Lysine

36
Q

This enzyme cleaves L F W and Y

A

Pepsin

37
Q

Which amino acids do chymotrypsin cleave?

A

F W Y

38
Q

T or F: Endopeptidase V8 cleaves Glutamate.

A

False. Glutamine.

39
Q

The amino acids valine, glycine, alanine, and serine are cleaved by _______________.

A

Elastase

40
Q

T or F: Cyanogen bromide cleaves the carboxyl side of every methionine residue

A

True

41
Q
A