Oxidative Phosphorylation Part 1 of Three Chapter 19

Oxidative Phosphorylation Part 1 –Electron-transport chain in mitochondria –Redox calculations –E-transport inhibitors –Building up the proton-motive force Key topics: To Know EOC Problem 1 is all about recognizing electron donors and acceptors…a quick review to make the rest of the chapter easy.

Mitochondria Review Chapters: 16,17,18 Chapter 19

SEM of Mitochondia

Mitochondia in Heart and Liver Attempts to show more inner membrane structure in heart mitochondria compared to liver mitochondria.

Dehydrogenases in Cytoplasm and Mitochondria

Quinones – 1 and 2 electron carriers EOC Problem 2 looks at the ubiquinone parts and their functions. Note the isoprene length.

Cytochromes One Electron Carrier

Cytochromes Easily Measured by Spectrophotometry

Difference Spectrum Vibrio harveyi. Taken from: Guerrero and Makemson 1989 Current Microbiology 18:67-73 Difference Spectrum (Reduced – Oxidized)

Iron Sulfur Protein Models

Electron Transport Carriers Redox Tower

Electron Carrier Sequence Determined from Inhibitors

Electron Transport Inhibitors

Isolation of Complexes from Mitochondria

Electron Carriers Arranged in Modules (Complexes)

Entry Points to Electron Transport EOC Problem 3: why is it that Succinate has to use FAD rather than NAD + ?

Complex I

Complex I Structure is Solved Efremov, RG et al., May, 2010 Nature 465: in cytoplasmic membrane Cytoplasm Periplasm Is this from mitochondria or bacteria?

Complex I Working H+H+ H+H+ H+H+ H+H+

Complex II

Entry Points to Electron Transport

Complex III

Complex IV

Complex IV : Proton Pumping/Oxygen Reduction

Yeast Complex III and IV Respirasome TEM (whole, Uranyl Acetate) Superimpose Xray Structures Composite of 100’s of Images Complex IV Complex III greenred

Electron Transport Summary EOC Problems 4 and 5 examine aspects of electron transfer and amounts of oxygen, NAD +, and other things such as inhibitors…great problems !

Summary of Electron Transport Complex I  Complex IV 1NADH + 11H + (N) + ½O 2 ——> NAD H + (P) + H 2 O Complex II  Complex IV FADH 2 + 6H + (N) + ½O 2 ——> FAD + 6H + (P) + H 2 O Difference in number of protons transported reflects differences in ATP synthesized.

Complex 1,3,4 or 2,3,4

Calculations Differences between half cells…Example of electron transfer from NADH to ubiquinone (going from NADH through Complex I to ubiquinone): NADH E o ’ = -.32 v Ubiquinone E o ’ = v ΔE o ’ = E o ’oxidized – E o ’ reduced = 0.045v – (-0.32v) ΔE o ’ = v

ΔG’ o Calculation What is the ΔG’ o for oxidation of NADH by ubiquinone ΔG’ o = - nƑΔE o ’Faraday Constant = 96,480 J/v. mole = 96.5 kJ/v. mole ΔG’ o = - (2) 96.5 kJ/v. mole (0.365v) = kJ/mole How Many “ATPs” is this worth?

Things to Know and Do Before Class 1.Where the DH’s are. 2.The electron transport players: flavin, Fe-S centers, cytochromes (and their properties), quinones, Cu Is it the ABCs of electron transport or the BCAs? 4.Effects of electron transport inhibitors. 5.Entry points and what each complex does. 6.How to calculate ΔG o ’ from ΔE o ’. 7.EOC Problems: 1-5.