What are the essentials of chemiosmosis?

matrix

cytosol

Cyt c

c1

c

2 x QH2

QH2

2 Q

Q

Complex III

Fe(III) Fe(II)

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

+4 e-

– H2O

Ubiquinone

Stigmatellin - co-crystallized in Cyt B1C

Inside thylakoid:4 H+ produced here

Outside thylakoid:4 H+ lost from here

carboxylation

regeneration

reduction

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

“Z-Scheme”

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?

Cytochorme b6f (analog of respiratory cytochrome b1c)

PSI Reaction Centercofactors only

PSI Reaction Center

Chlpigments

E-acceptor