Ackerman Lectures 5-8 Flashcards Preview

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Flashcards in Ackerman Lectures 5-8 Deck (66):
1

complex I

NADH dehydrogenase; NADH is donor, Q is acceptor; cofactors are FMN, FeS; OxPhos E coupling site 1; 4H+ pumped per 2e- transferred (-17kcal/mol)

2

complex II

succinate dehydrogenase; 4 su's; succinate is donor, Q is acceptor; cofactors are FAD, FeS, b-type heme (-0.7kcal/mol)

3

complex III

cytochrome b-c1; 11 su's; OxPhos E coupling site 2; QH2 is donor, cyto coxid is acceptor; cofactors are b and c hemes, Rieske FeS cluster; prots are cytochrome b and c1, Rieske iron-sulfur prot; 2H+ pumped per 2e- transferred, plus 2H+ dumped outside from quinol (-9.6kcal/mol)

4

complex IV

cytochrome c oxidase (COX); 13 su's; OxPhos E coupling site 3; cyto cred is donor, O2 is acceptor; cofactors are a-type hemes and copper (CuA and CuB); 2H+ pumped per 2e- transferred plus 2H+ used inside to make H2O (-26kcal/mol)

5

complex V

ATP synthase

6

bound redox centers of the ETC

flavins, copper, FeS centers, heme

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heme A

IV

8

heme B

II and III

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heme C

III

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flavins

accept 2e-, 2H or 1e-, 1H (all others are just one, not two)

11

ubiquinone/coenz Q (semiquinone, ubiquinol)

3 oxid states; carries 1 or 2 e-; carries both e- and protons; isoprenoid side chain

12

cytochrome c

peripheral prot att to IMS face of inner memb; heme C is coval liganded

13

entry paths into ETC

all flavo-prots; CoQ is common acceptor; in each path, flavin + Q

14

respiratory substrates

NADH, succinate, fatty acyl-CoA, glycerol-3-P (all release 2e- at once)

15

subst-level phos

high-E metabolites-->7.3kcal/mol free E when cleaved (1,3-BPG, PEP, succ-CoA, phosphocreatine)

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oxid phos

employs O2 as final acceptor of e- and H+ from metab oxid rxns

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FAD

complex II, G3PDH, FA-CoA DH; 2 or 1 e- and H+

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FMNH2

complex I; 2 or 1 e- and H+

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FeS centers

1e-; Complex I, II, or III (III=Rieske type w/2Cys, 2His)

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Heme A

1e-; complex IV

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Heme B

1e-; complex II and III

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Heme C

1e-; complex III; w/Cys sulfhydryls att

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copper

1e-; complex IV

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complex I rxn

NADH + H+ --> FMN; FMNH2-->(FeS)9 --> CoQ; must rel 2 e- at once

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complex II rxn

succinate --> FAD; FADH2-->(FeS)3-->Cyt b --> CoQ; must rel 2 e- at once

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NADH shuttle (G3PDH)

G3P-->FAD; FADH2-->CoQ; must rel 2 e- at once

27

b-oxid path (FA-CoADH)

FA-CoA -->FAD; FADH2-->CoQ; must rel 2 e- at once

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NADH as substrate

IMS: matrix is 10 per 2e- transferred (pmf=10)

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SUC or FA-CoA or Gly3P as substrate

IMS: matrix is 6 per 2e- transferred (pmf =6)

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respiration proton gradient

chem (pH) and charge gradients w/IMS more positive than matrix; contrib to change in free E as pmf (excess protons in IMS)

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ATP synthase

transducer that captures pmf E and converts it to chem bond E (1mol ATP made for every 4H+ translocated from IMS back to matrix); pmf (electrochem E) converted to rotation (mech E); E conserved in b-y phosphodiester (anhydride) bond b/w ADP and Pi

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F1

peripheral memb prot catalytic sites (3); a3b3y3e

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F0

integral memb prot proton channel; d+ab2c10

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catalytic head of ATP synthase

a3b3; catalytic site in each of 3 b subunits interfaces

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proton pump of ATP synthase

a(c ring); H+ transloc causes to rotate

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ATP synthase rotor

ye; att to c ring; rotate in unison

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ATP synthase stator

b2d + d; prevents rotation of a3b3 head gp

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Keq of ATP hydrolysis

1; cat coop b/w 3 sites; freely reversible; ATP+H2O-->ADP+Pi and ADP+Pi-->ATP+H2O; Kd = 10^-12 (tight)

39

bdg change mech for F1 catalysis

affin for ATP formed at one cat site red by 10^6 when subst (ADP+Pi) bd to another cat site; pos coop

40

ATP hyrdolysis

powers H+ pumping from matrix to IM; allows release of ADP and Pi

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ATP synthesis

H+ moving from IM to matrix through, causes C to rotate; form ATP when tight, release when more ADP and Pi binds and becomes tight

42

oligomycin

inhibits H+ mvmt; blocks H+ translocation; [H+] out v in increase to where /\G is positive; oxid stops since H+ mvmt through comps I, III, IV is coupled to e- transfer

43

NBD-Cl

inhibits F1 catalysis; eliminates /\p and ATP synth stops b/c E no longer available

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[ADP]

ctrls rate of oxid phos

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respiratory control ratio (RCR)

P:O; indicates coupling efficiency in mito; =active/resting respiration

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P:O NADH

pmf / pmf req to phosphorylate ADP to ATP = 10/4 = 2.5

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P:O FADH2

pmf / pmf req to phosphorylate ADP to ADP = 6/4 = 1.5

48

glucose metabolism

686kcal/mol / 7.3kcal/mol to make ATP = 94 mol ATP; efficiency of converting food to ATP is 34%; 94 x 0.34 = 32 mol ATP

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UCP

disengage H+ grad from ATP synth; provide alt path through IM; dissipates pmf as heat (entropic); abundant in brown fat; decrease efficiency of OXPHOS; increase respiration, unctrl'd dissip of H+ grad

50

2,4-DNP

enters IMS, becomes protonated, diffuses through lipid bilayer of IM into matrix; can collapse /\p-->unctrl'd fuel oxid; no ATP made; futile cycle of H+ out/in generates heat; used as weight-loss, but lethal (hyperthermia)

51

rotenone

complex I; inhibit e-transport, no /\p, no ATP synth

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amytal

complex I; inhibit e-transport, no /\p, no ATP synth

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piericidin

CoQ analog; inhibit e-transport, no /\p, no ATP synth

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malonate

complex II; inhibit e-transport, no /\p, no ATP synth

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antimycin A

complex III; inhibit e-transport, no /\p, no ATP synth

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cyanide

complex IV; inhibit e-transport, no /\p, no ATP synth

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carbon monoxide

complex IV; inhibit e-transport, no /\p, no ATP synth

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azide

complex IV; inhibit e-transport, no /\p, no ATP synth

59

oligomycin

inhibits Fo subunit of ATP synthase; blocks respiration; inhibits dissipation of H+ grad, E barrier blocks ET-coupled H+ pumpking; e-stop moving, O2 not reduced to H2O

60

cyanide poisoning

can overcome inhib of I, II, or III but NOT IV; antidote kit can restore oxphos (amyl nitrite, Na nitrite, Na thiosulfate)

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redox shuttles in mito IM

carry red equivs from cyto NADH to mito for oxphos

62

glycerol phosphate shuttle

most common; NADHcyt oxid provides FADH2 in mito; cyto and mito forms of G3PDH (cyt uses NADH to red DHAP; mito uses FAD to xodi G3P); ignores comp I; regen NAD+

63

malate-aspartate shuttle

cyto and mito forms of malate DH and Asp aminotransferase (cyto uses NADH to reduce OAA; mito uses NAD+ to oxid malate); stays where created b/c no OAA/a-KG carrier

64

mtDNA

17kb; 13 prots, all rRNA and tRNA to translate them; struc su's of hyphob, integ memb domains of I, II, IV, V; w/o are rho-0 petites

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p^0 cells

can't respire, can't make ATP by oxid phos; still have mito, but different from normal cells

66

mito encephalomyopathies (genetic disease of OXPHOS)

caused by mutation in mtDNA; mutation/deletion in prot-coding gene; random deletions (likely tRNA gene, pheno sim to rho^0); severity dep on mutant load (# mutant v normal copies); could have same genetic defect w/diff morphology (go to diff places in diff ppl)