Protein structure and folding Part 2 Flashcards

1
Q

Which arrangement of globular protein may or may not independently stable and has a recognizable folding pattern/ particular arrangement

A

Motif

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2
Q

Which arrangement of globular protein is independtly stable?

A

Domain

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3
Q

How do we determine protein structure

A
  1. Xray crystallography
  2. NMR
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4
Q

What are pros of X-ray crystallography

A

no size limit, well stablished

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5
Q

Pros of NMR

A

no need to crystallize
see many hydrogens
protein in solution (more natural)

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6
Q

Cons of X-ray crystallography

A

difficult for membrane protein
cannot see hydrogens

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7
Q

Cons of NMR

A

works best for small protein
difficult fot insoluble protein

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8
Q

Motif equals

A

structure

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9
Q

If a particular arrangement is related to some function, it is a

A

domain

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10
Q

Domain equals

A

function

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11
Q

All protein begins life on ribosomes in what state

A

unfolded or non-native state

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12
Q

What dirves protein to go from Non-native to native state

A
  1. Hydrophobic effect
  2. Maximization of H-bond and stavilizing ion pair
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13
Q

What drives protein folding

A

increase in entropy fo water

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14
Q

The hydrophilic sheels of globular protein are stabilized by

A

hydrogen bond, sulfide bond and salt bridges

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15
Q

Loss of structural integrity with accompany loss of activity is called

A

Denaturation

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16
Q

Protein can be denatured by

A

heat or cold
pH extremes
organic solvents
chaotropic agents

17
Q

What are chaotropic agent

A

urea, guanidinium hydrochloride (GdnHCl)

18
Q

Main takeaway from Christian Anfinsen experiment

A

the cow stomach has Ribonuclease A which digest RNA in food. It is a very stable protein because it is in digestive tract of pH 4
β mercaptoethanol and Urea will denature and reduce protein
protein always fold simultaneously into native struture

19
Q

8 cysteines can form how many disulfide bonds

A

4

20
Q

What structure does disulfide bond stabilize

A

tertiary structure

21
Q

What is the function of β mercaptoethanol

A

reducing agent of disulfide bond

22
Q

What is the function of urea

A

denature protein

23
Q

Do disulfide influence/promote folding?

A

no, they stabilize native state

24
Q

why is native state thermodynamically favorable

A

weak interactions are maximized and most protein do not have disulfide bond. These add up and stabilize protein

25
Q

This state of protein makes numerous weak interaction with solvent. what is this state?

A

unfolded state

26
Q

Describe the entropy of water to maximize H bonds forming an ordered layer around non polar solute?

A

decreased entropy of water

27
Q

Main takeaway from Levinthal’s paradox

A

protein folding pathway, folding funnels

28
Q

This assist in both types of process, and prevent unwanted side reaction

A

Chaperones

29
Q

Which chaperons serves as a “holding” function recognizing stretches of hydrophobic residues in unfolded protein

A

Hsp 70

30
Q

This chaperons provides a “folding chamber” where proteins can fold in peace

A

Chaperonins