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Flashcards in Proteins Deck (38)
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Questions

Answers

2

Asp

4

3

Glu

4

4

His

6

5

Cys

8.4

6

Tyr

10.5

7

Lys

10.5

8

Arg

12.5

9

carboxylate

2.2

10

amino

9

11

Primary

AA sequence

12

Secondary

H-bonds. alpha-helix, beta-sheet, beta-turn

13

Teritiary

Folding of secondary structures. Folded forces (hydrophobic, H bonding, van der waals, electrostatic)

14

Quaternary

2 or more subunits. Can exhibit coopertivity. Entropy favors unfolded state

15

K(f)

[folded protein]/[unfolded protein]

16

Oxygen

Limited solubility

17

Myoglobin

Function: Store oxygen in muscle for release during O2 deprevation. Structure: Monometric protein with heme. Noncooperative. O2 binding independent of pH, CO2, 2,3 BPG

18

Hemoglobin

Function: Carry O2 from lungs to tissues, alsotransport CO2 and H+. Structure: 2 alpha, 2 beta units with hemes, nonpolar residues (His) protect Fe2+ oxidation to Fe3+ (does not bind O2), bent O2 binding favored (CO2 want to be linear). O2 affinity dependent on pH, CO2, and 2,3 BPG

19

Globin pocket

Hydrophobic interior (protect Fe2+ from oxidation), polar exterior (increases solubility of Hb)

20

Hb (fetal)

Ser replaces His so O2 binds HbF tighter than HbA due to HbF decreased affinity for BPG (via loss of His)

21

BPG

Binds Hb and reduces its affinity for O2 by stabilizing T-form. High altitude increase [BPG].

22

Oxygenation of Hb

Pulls heme into plane and stabilizes R state

23

Bohr effect

Lowering pH, increasing [H+], increasing [CO2], causes Hb to release more O2. Opposite occurs in lungs where high [O2] causes Hb to release H+ and CO2

24

Carbamino-Hb

N-terminal residue of deoxyHb reacts with CO2 forming carbamino-Hb

25

Fibrous proteins

Structure: insoluble, polypeptide chain is parallel to single axis, strong and highly cross-linked. Function: structure

26

Collagen

Structure: requires 8 post-translational modifications (enzymes for this are the targets for drugs to inhibit collagen accumulation), primary sequence (1/3 gly)--> minor helix (type II, 3 residue turns)--> triple helix (3 type II stablized by H bonding)-->tropocollagen (post translational modification)-->fibril--> fiber. Function: bone formation.

27

Hydroxylapatite

40nm gaps in collagen fibril serve as nucelation points for hydroxylapatite deposition and bone formation

28

Pre-procollagen

Pre: signal sequence to insert into ER membrane

29

Pro-collagen

Pro: N and C terminal sequences that are cleaved after secretion forming tropocollagen

30

Elastin

Protein of tendons and blood vessel walls. Gives structure ability to spring back into shape. Contain cross links called desmosine (4 lys residues) that provide elastic property. Random coil conformations