Lecture 7 August 15, 2005 Lehninger (4 th Edition), Chapter 16 Oxidative phosphorylation: Chapter 19

LNC Fig Products from one turn of the Krebs cycle

LNC Fig.16.7 the only membrane- bound enzyme in the TCA cycle

THE GLYOXYLATE CYCLE LNC Chapter 16, pages

LNC Fig Note that the figure in the 3 rd edition has an error (there is an O instead of an H) C6C6 C6C6 C4C4 C4C4 C4C4 C2C2 C2C2 C2C2 from oxidation of fatty acids

LNC Fig.16.22

LNC Fig isocitrate dehydrogenase: inactivated by phosphorylation isocitrate lyase: inactivated by low ATP (high AMP/ADP)

ELECTRON TRANSPORT AND OXIDATIVE PHOSPHORYLATION Chapter 19 in LNC

HEAT CO 2 HEAT CO 2 “Guinea Pig” “Charcoal”

“…..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

Carbohydrate + oxygen => carbon dioxide and water C 6 H 12 O O 2 => 12 H 2 O + 6 CO 2 + ENERGY

RESPIRATION

2

Wild type SDHC

Outer membrane Inner membrane Intermembrane space Matrix

LNC Fig.19.7

the arrangement of the complexes in the inner membrane and the order of electron flow

NADH

LNC Fig TMPD/ascorbate CN - rotenone malonate antimycin Glutamate/malate succinate Succinate dehydrogenase membrane bound enzyme of Krebs cycle Four integral membrane protein complexes Two mobile carriers: ubiquinone and cytochrome c

LNC Fig.19.8

oxidized Coenzyme Q or Q reduced Coenzyme Q or QH 2 LNC Fig.19.2 lipid-soluble polyisoprene chain

Heme + apoprotein cytochrome LNC Fig.19.3

Structure of cytochrome c

LNC Fig.19.4

NON-HEME IRON - SULFUR CENTERS [Fe 2 -S 2 ] [Fe 4 - S 4 ]

LNC Fig.19.5

[Fe 2 -S 2 ] LNC Fig.19.5

[Fe 4 -S 4 ] LNC Fig.19.5

A bacterial ferredoxin

NADH O2O2

LNC Fig or 8 NADH + Q + H +  NAD + + QH 2

LNC Fig Architecture of Succinate Dehydrogenase and Reactive Oxygen Species Generation Victoria Yankovskaya,1* Rob Horsefield,2* Susanna To¨rnroth,3* Ce´sar Luna-Chavez,1,4† Hideto Miyoshi,5 Christophe Le´ger,6‡ Bernadette Byrne,2 Gary Cecchini,1,4§ So Iwata2,3,7§ SCIENCE 31 JANUARY 2003 VOL 299, p [2Fe-2S] [3Fe-4S] [4Fe-4S] succinate Succinate + Q  fumarate + QH 2

Complex III 8-11 polypeptides two cytochromes, b and c 1 one iron-sulfur center LNC Fig QH cyt c (Fe +3 )  Q + 2 cyt c (Fe +2 ) (ignore the protons for the moment)

LNC Fig.19-11b Complex III 8-11 polypeptides two cytochromes, b and c 1 one iron-sulfur center

LNC Fig The Q Cycle Net equation QH cyt c ox + 2H + in  Q + 2 cyt c red + 4H + out 2 Fe +3 2 Fe +2

Cyt c 1 red + Cyt c ox  Cyt c 1 ox + Cyt c red Fe +3 Fe +2 

LNC Fig19-13a Complex IV - cytochrome oxidase polypeptides cytochromes a and a 3 two copper centers 4 cyt c (Fe +2 ) + O 2 + 4H+  4 cyt c (Fe +3 ) + 2 H 2 O ( and protons pumped)

Complex IV (schematic) LNC Fig cyt c red + O H + 4 cyt c ox + 2 H 2 O Fe +2 Fe +3

An excerpt from Table 14-7, in reverse order NADH + ½ O 2 + H +  NAD + + H 2 O  E ’ o = v v = v  G ’ o = -n F  E’ o = - 2 x 96,480 J/V x mole x v = kJ/mole NADH

End of Lecture 7 Mon, Aug. 15, 2005