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Flashcards in protein folding Deck (32):
1

the disruption of tertiary and secondary protein structure that leads to los of protein function

denaturation

2

increases the rate of molecular motion/vibration, causing disruption of H-bonds, leads to protein unfolding

heat/temperature

3

cause protonation/deprotonation of sidegroups, alters H-bonding and salt bridges
proteins become insoluble and precipitate out of solution as they reach their isoelectric points

strong acid/base, pH changes

4

explain how chaperones aid in protein folding

Hsp 70 attaches to polypeptide chain first
uses ATP
promotes first folding of the protein
Hsp 60 (GroEL) attracts partially folded peptide chain
GroES "lid" comes on top of Hsp 60 body to keep protein inside.
hydrolysis of ATP causes hydrophilic environment in chaperone
promotes folding of protein

5

interfere with hydrophobic interactions; substitute or interfere in H-bonding

alcohols

6

disrupt hydrophobic interactions, leading to protein unfolding

detergents

7

interfere with salt/bridges/charge interaction in proteins
can "extract" water molecules from protein surface leading to protein aggregation and precipitation

high salt concentration

8

eliminate disulfide bridges causing unfolding

reducing agents

9

disrupts weak forces that stabilize tertiary protein structure

mechanical stress

10

when do proteins start folding

as they are made during translation

11

protein folding is assisted by

chaperones

12

chaperones assist protein folding in two ways

preventing inappropriate protein-protein interactions
help folding occur rapidly and precisely

13

how does Hsp 60 attract partially folded protein

initial hydrophobic environment inside protein

14

explain protein degradation

ubiquitin is added to protein that needs degraded
E1 E2 E3 in that order are used to attach 3 more ubiquitin molecules
protein travels to proteasome where degradation to amino acids occurs

15

protein disease causing agents that are not commonly genetically related but are usually ingested

prions

16

three characteristics of fibrous proteins

typically contain high proportions of alpha helices and beta sheets
often have structural roles
water insoluble

17

three characteristics of collagen

part of connective tissue matrix
left handed helices twist to form right handed triple helix
impart special properties to structure

18

three amino acids common in collagen

glycine
proline
hydroxyproline

19

three similarities of hemoglobin and myoglobin

similar polypeptide tertiary structure
same heme group to bind oxygen
very similar functions

20

two big differences between hemoglobin and myoglobin

myoglobin is a monomer and hemoglobin is a tetramer
different physiological binding affinities for oxygen

21

three additional characteristics of myoglobin

8 alpha helices
found in skeletal and cardiac muscles
has higher affinity for oxygen than hemoglobin

22

three additional characteristics of hemoglobin

2 alpha and 2 beta helices
found in red blood cells
transport oxygen from lungs to tissues
cooperative oxygen binding

23

once alpha 1 helix accepts oxygen the other subunits will form the appropriate shape to accept oxygen

cooperative oxygen binding

24

what element is essential for oxygen binding

iron

25

what amino acid is associated with binding oxygen

histidine

26

lower ph means ____oxygen binding

lower

27

four factors affecting the amount of oxygen bond by hemoglobin

availability of oxygen
binding of first oxygen molecule
ph
presence of CO

28

how does carbon monoxide interfere with oxygen binding

CO kicks off oxygen and binds to Fe much stronger than oxygen

29

adult hemoglobin

2 alpha 2 beta

30

fetal hemoglobin

2 alpha 2 gamma

31

sickle cell hemoglobin

2 alpha 2 beta with valine instead

32

valine replaces what at what subunit

glutamate at beta subunit