1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I
description
Transcript of 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I
![Page 1: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/1.jpg)
1. Structure of photosystem I at atomic resolution (PS I)
2. Function of PS I
3. Genetic analysis of structure-function relations
4. Two branches in electron transport in PS I
5. PS I a photo-nano-switch
PS I is a light driven plastocyanin ferredoxin oxidoreductase.
Quantum efficiency for electron transfer is 1
PS I is part of the photosynthetic apparatus. A membrane protein chlorophyll complex one of the 4 complexes that make the transmembrane oxidoreductase system that oxidize water to O2 and reduces NADP+ to NADPH + H+, pump H+ that drive ATP synthesis.
![Page 2: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/2.jpg)
![Page 3: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/3.jpg)
PS I is part of the photosynthetic apparatus. A membrane protein chlorophyll complex one of the 4 complexes that make the transmembrane oxidoreductase system that oxidize water to O2 and reduces NADP+ to NADPH + H+, pump H+ that drive ATP synthesis.
![Page 4: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/4.jpg)
![Page 5: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/5.jpg)
Composition
12 subunits A-M, X (no H, G), 9 of them are transmembrane peptides. C, D & E are attached at the outside (storma).
M.W. 255 kDa
96 Chlorophylls, 22 carotenoids, 2 phylloquinons, 3 [4Fe4S] clusters.
![Page 6: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/6.jpg)
Subunit arragem-ent view from stroma
![Page 7: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/7.jpg)
![Page 8: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/8.jpg)
![Page 9: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/9.jpg)
FeSA/B
FeSX
Subunit C
Subunits A, B
![Page 10: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/10.jpg)
The electron transfer chain is attached on subunits A, B & C.
P700, A0, A1, Fx, FA & FB.
P700- Chla dimer, parallel rings 3.5 A apart, perpendicular to the membrane, rings I, II partially overlap. Asymmetry: A branch has H bonds to H680 and to water. Lower spin density in the A ring of the radical P700+..
A0- Chla monomer (eC-A2, eC B2) has Mg-H-water-Asn591.
A1- phylloquinone, hydrophobic pocket LeuA722, TrpA697, TrpB673.
Two branches? QA-Fx 200ns, QB-Fx 20ns, B-branch is faster?
Fx,- 4Fe4S iron sulfur cluster, lowest potential in biology.
FA and FB- 4Fe4S iron sulfur clusters
![Page 11: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/11.jpg)
![Page 12: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/12.jpg)
FeSB
FeSA
FeSX
PQ
Ao (CHL)P700 (CHL2)
![Page 13: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/13.jpg)
![Page 14: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/14.jpg)
The electron transfer chain is attached on subunits A, B & C.
P700, A0, A1, Fx, FA & FB.
P700- Chla dimer, parallel rings 3.5 A apart, perpendicular to the membrane, rings I, II partially overlap. Asymmetry: A branch has H bonds to H680 and to water. Lower spin density in the A ring of the radical P700+..
A0- Chla monomer (eC-A2, eC B2) has Mg-H-water-Asn591.
A1- phylloquinone, hydrophobic pocket LeuA722, TrpA697, TrpB673.
Two branches? QA-Fx 200ns, QB-Fx 20ns, B-branch is faster?
Fx,- 4Fe4S iron sulfur cluster, lowest potential in biology.
FA and FB- 4Fe4S iron sulfur clusters
![Page 15: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/15.jpg)
![Page 16: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/16.jpg)
![Page 17: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/17.jpg)
The electron transfer chain is attached on subunits A, B & C.
P700, A0, A1, Fx, FA & FB.
P700- Chla dimer, parallel rings 3.5 A apart, perpendicular to the membrane, rings I, II partially overlap. Asymmetry: A branch has H bonds to H680 and to water. Lower spin density in the A ring of the radical P700+..
A0- Chla monomer (eC-A2, eC B2) has Mg-H-water-Asn591.
A1- phylloquinone, hydrophobic pocket LeuA722, TrpA697, TrpB673.
Two branches? QA-Fx 200ns, QB-Fx 20ns, B-branch is faster?
Fx,- 4Fe4S iron sulfur cluster, lowest potential in biology.
FA and FB- 4Fe4S iron sulfur clusters
![Page 18: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/18.jpg)
![Page 19: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/19.jpg)
![Page 20: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/20.jpg)
The electron transfer chain is attached on subunits A, B & C.
P700, A0, A1, Fx, FA & FB.
P700- Chla dimer, parallel rings 3.5 A apart, perpendicular to the membrane, rings I, II partially overlap. Asymmetry: A branch has H bonds to H680 and to water. Lower spin density in the A ring of the radical P700+..
A0- Chla monomer (eC-A2, eC B2) has Mg-H-water-Asn591.
A1- phylloquinone, hydrophobic pocket LeuA722, TrpA697, TrpB673.
Two branches? QA-Fx 200ns, QB-Fx 20ns, B-branch is faster?
Fx,- 4Fe4S iron sulfur cluster, lowest potential in biology.
FA and FB- 4Fe4S iron sulfur clusters
![Page 21: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/21.jpg)
![Page 22: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/22.jpg)
![Page 23: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/23.jpg)
![Page 24: 1. Structure of photosystem I at atomic resolution (PS I) 2. Function of PS I](https://reader035.fdocuments.in/reader035/viewer/2022062314/568145ae550346895db2a900/html5/thumbnails/24.jpg)