August 15, 2005

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Lecture 7

• August 15, 2005
• Lehninger (4th Edition), Chapter 16
• Oxidative phosphorylation Chapter 19

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Products from one turn of the Krebs cycle
LNC Fig.16.13
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the only membrane- bound enzyme in the TCA cycle
LNC Fig.16.7
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THE GLYOXYLATE CYCLE
LNC Chapter 16, pages 623-626
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C2
C4
C6
C4
C6
C4
C2
C2
LNC Fig.16-20
Note that the figure 16-16 in the 3rd edition has
an error (there is an O instead of an H)
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LNC Fig.16.22
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isocitrate lyase inactivated by low ATP (high
AMP/ADP)
isocitrate dehydrogenase inactivated by
phosphorylation
LNC Fig.16.23
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ELECTRON TRANSPORT AND OXIDATIVE PHOSPHORYLATION
Chapter 19 in LNC
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CO2
Guinea Pig
Charcoal
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..this fire stolen from heaven, this torch of
Prometheus, does not only represent an ingenious
and poetic idea, it is a faithful picture of the
operations of nature, at least for animals that
breathe... the torch of life lights itself at the
moment the infant breathes for the first time,
and it does not extinguish itself except at
death. Lavoisier, 1789
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Carbohydrate oxygen gt carbon dioxide and
water
C6H12O6 6 O2 gt 12 H2O 6 CO2
ENERGY
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RESPIRATION
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2
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Wild type SDHC
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Outer membrane
Inner membrane
Matrix
Intermembrane space
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LNC Fig.19.7
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the arrangement of the complexes in the inner
membrane and the order of electron flow
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succinate
Succinate dehydrogenase membrane bound enzyme
of Krebs cycle
Four integral membrane protein complexes Two
mobile carriers ubiquinone and cytochrome c
LNC Fig.19.15
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LNC Fig.19.8
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oxidized Coenzyme Q or Q
reduced Coenzyme Q or QH2
LNC Fig.19.2
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Heme apoprotein cytochrome
LNC Fig.19.3
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Structure of cytochrome c
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LNC Fig.19.4
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NON-HEME IRON - SULFUR CENTERS Fe2-S2 Fe4 -
S4
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LNC Fig.19.5
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Fe2-S2
LNC Fig.19.5
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Fe4-S4
LNC Fig.19.5
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A bacterial ferredoxin
LNC Fig.19.5
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O2
NADH
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7 or 8
NADH Q H ? NAD QH2
LNC Fig.19.9
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Architecture of Succinate Dehydrogenase and
Reactive Oxygen Species Generation Victoria
Yankovskaya,1 Rob Horsefield,2 Susanna
Tornroth,3 Cesar Luna-Chavez,1,4 Hideto
Miyoshi,5 Christophe Leger,6 Bernadette Byrne,2
Gary Cecchini,1,4 So Iwata2,3,7 SCIENCE 31
JANUARY 2003 VOL 299, p.700 www.sciencemag.org
succinate
2Fe-2S 3Fe-4S 4Fe-4S
Succinate Q ? fumarate QH2
LNC Fig.19.10
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Complex III 8-11 polypeptides two cytochromes, b
and c1 one iron-sulfur center
QH2 2 cyt c (Fe3) ? Q 2 cyt c
(Fe2) (ignore the protons for the moment)
LNC Fig.19-11
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Complex III 8-11 polypeptides two cytochromes, b
and c1 one iron-sulfur center
LNC Fig.19-11b
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The Q Cycle
LNC Fig.19-12
Net equation QH2 2 cyt cox 2Hin ? Q 2
cyt cred 4Hout
2 Fe3
2 Fe2
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Cyt c1 red Cyt c ox ? Cyt c1 ox Cyt c
red
Fe3
Fe3
Fe2
Fe2
?
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Complex IV - cytochrome oxidase 9 - 13
polypeptides cytochromes a and a3 two copper
centers
4 cyt c (Fe2) O2 4H ? 4 cyt c (Fe3)
2 H2O ( and protons pumped)
LNC Fig19-13a
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Complex IV (schematic)
4 cyt cred O2 4 H 4 cyt cox
2 H2O
Fe2
Fe3
LNC Fig.19-14
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NADH ½ O2 H ? NAD H2O
DEo 0.816 v 0.320 v 1.136 v
DGo -n F DEo - 2 x 96,480 J/Vxmole x
1.136 v - 220 kJ/mole NADH
An excerpt from Table 14-7, in reverse order
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End of Lecture 7 Mon, Aug. 15, 2005