what’s new in this book’s presentation of respiration? what’s confusing?

What’s new in this book’s presentation of respiration?What’s confusing?

How many proteins are involved?What are their roles?

Which metalloproteins have their own names?

What are the essentials of chemiosmosis?

What molecule is responsible for creating the H+ gradient?

What are the two requirements of chemiosmotic hypothesis?

How many and which metals are involved in respiration?In what types of centers are these metals in?

What is the reaction that provides the energy for ATP formation?

matrix

cytosol

Cyt c

c1

c

2 x QH2

QH2

2 Q

Q

Complex III – creates H+ gradient

H+‘s are pulled in from inside for Q redn

H+ ‘s are

released

outside for

QH2 redn

Fe(II) Fe(III)

Complex IV – Cytochrome C Oxidase

Cu(II) Cu(I)

Cu(II)—Cu(I) Cu(I)—Cu(I)

oxy

peroxy

Ferryl

oxidized

reduced

H+ limiting

H+ limiting

Complex IV – Cytochrome C Oxidase

– H2O

O-O2-

– H2O

START

Internal redox

Ubiquinone

Stigmatellin - co-crystallized in Cyt B1C

The magical partnership of Metal and organic redox

Photosystem I

SUN CATCHER Each lobe of clover-leaf-shaped crystal of photosystem I contains 12 different proteins,

shown here in different colors with only the protein backbone of each depicted. Amid the proteins are 96 chlorophylls (pale yellow) as well as other cofactors.

Photosystem I

How do chl molecules behave as attennae?

Inside thylakoid:4 H+ produced here

Outside thylakoid:4 H+ lost from here

carboxylation

regeneration

reduction

What are the two processes in PS and what are their names?

What is the OEC?

Inside thylakoid:4 H+ accumulates here

Outside thylakoid:4 H+ lost from here

carboxylation

regeneration

reduction

Net ET reaction: H2O PSII plastoQ cyt b6f plastocyanin PSI Fe2S2 NADP+

“Z-Scheme” How is the energy of light converted into

chemical energy in the 1st step?

How many and which metals are involved in

PS?

Mn4O4 cluster in PSIIparallels Complex I in respiration

Plastocyanin in PSIparallels cyt c in respiration

PSI parallels Complex IV= cyt c oxidase in respiration

+ 4e-

Eox (V)

+1.2 V

+0.6 V

0.0

-0.6 V

-1.2 V

confusing?

What are the similarities and differences between

respiration and photosynthesis?

1. Cristae and thylakoid: inner membrane structures2. Cyt bd in mitochondria ~ cyt b6f in chloroplasts

3. Small organic electron/proton carriers4. Multi-metal site for multi electron processes5. Reactive centers embedded in membranes

6. Creation of proton gradient7. PSII reduces a Q to QH2; PSI is like complex IV

8. Plastocyanin functions like Cyt c9. Use of aa residue as radical (Tyr)

PSII @ 3.5 Å resolution

Cytochorme b6f (analog of respiratory cytochrome b1c)

PSI Reaction Centercofactors only

PSI Reaction Center

Chlpigments

E-acceptor