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Nitrogenáza

4Fe – 4S cluster. P-cluster. FeMo-cluster. Nitrogenáza.  -subunit. FeMo -cofactor. [ 4 Fe : 4 S ] cluster.  -subunit. P -cluster. Nitrogenáza. Fe-protein. MoFe-protein. FeMo-protein tetramer (  2  2). MgATP. Fe-protein dimer (  2). P. Fe S. FeMo-co. M. 220 kDa. MgATP.

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Nitrogenáza

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  1. 4Fe–4S cluster P-cluster FeMo-cluster Nitrogenáza

  2. -subunit FeMo-cofactor [4Fe:4S] cluster -subunit P-cluster Nitrogenáza Fe-protein MoFe-protein

  3. FeMo-protein tetramer (2 2) MgATP Fe-protein dimer (2) P FeS FeMo-co M 220kDa MgATP 60kDa Nitrogenáza N2+8H++8e–+16MgATP 2NH3+H2+16MgADP+16Pi

  4. homocitrate [Fe8S8] model [Fe8S8] model MoFe cluster P cluster Nitrogenáza

  5. Nitrogenáza–Mo-centrum

  6. (a) (b) Cys 61 Cys 61 wat wat Ser 90 Ser 90 Cys 153 Cys 153 Cys 87 Cys 87 wat wat Cys 93 Cys 93 Cys 151 Cys 151 Ser 186 Ser 186 Cys 68 Cys 68 P-cluster MoFe-proteinu

  7. ferredoxiny, flavodoxiny 6H++H2 2NH3 e– e– Fe-protein Fe-protein 2H+ H2 MgATP MgATP + Pi FeMo-co P-klastr 19Å + 70Å P-klastr ATP FeMo-co Fe protein (dimer) FeMo protein (tetramer) ATP ADP+Pi G° =–30,5kJ·mol–1 Fixace dusíku: Nitrogenáza

  8. 2ADP+2Pi (Ferridoxin)red (Fe-protein)ox (MoFe-protein)red N2+8H+ oxidativnítransportelektronu (Ferridoxin)ox (Fe-protein)red (MoFe-protein)ox 2NH3+ H2 2ATP 8 krát Nitrogenáza– fixace dusíku

  9. Mo-Fe protein P-cluster 2 ADP 2 ATP Fe N e– Fe4S4 cluster N Fe Mo Fe protein Mo-Fe-S cluster Nitrogenáza– přenos elektronu

  10. (a) (b) Nitrogenáza– přenos elektronu

  11. +N2 Mo(III) 14MoMo(N2)1 Mo(III) –NH3 e Mo(III) 13Mo(NH3) Mo–N=N–2 Mo(IV) e H+ Mo(IV) 12{Mo(NH3)}+Mo–N=N–H3 Mo(IV) H+ H+ Mo(IV) 11Mo–NH2 {Mo=N–NH2}+4 Mo(VI) e e Mo(V)10{Mo–NH2}+Mo=N–NH25 Mo(V) H+ H+ Mo(V) 9Mo=NH {Mo=N–NH3}+6 Mo(V) e e –NH3 Mo(VI)8{Mo–NH}+MoN7 Mo(VI) H+ Nitrogenáza–reduktivní kroky

  12. Tepelné zabarvení reakcí N2+ 3H22 NH3H = – 96 kJ/2mol NH3 N2+ H2HN=NH H = + 213 kJ/mol HN=NH+ H2H2N–NH2H = – 114 kJ/mol H2N–NH2+ H22 NH3H = – 191 kJ/mol

  13. Oxomolybdenové enzymy O || (RS)2,3–Mo(VI)=O O || (RS)2–Mo(VI)=S O || (RS)2–Mo(VI)=O oxido- vaná O || (RS)3–Mo(IV) O || (RS)2–Mo(IV)–SH O || (RS)3,4–Mo(IV) redu- kovaná Sulfito oxidáza Xantin oxidáza Nitráto reduktáza

  14. P-klastr SO32– SO42– OH2 III III Cytochrom c(red) Cytochrom c(ox) II II Cytochrom c(ox) Cytochrom c(red) III Sulfito oxidáza Sulfito oxidáza: Konverze sulfitůna sulfáty

  15. Mo Y YO X XO Mo Molybden Dusík Kyslík Síra Uhlík Oxotransferáza

  16. xantin kyselina močová Xantin oxidáza Xantin oxidáza

  17. Ni Ni Ni Ni Ni Ni Ni Ni Ni + +H3NCOO– Ni Ni Ni Ureáza Ureáza

  18. CO2 CO2 F420 G° = –1,3kJ HCO2H G° = +23kJ F420 CH2O G° = –44,8kJ F420 Redukce CO2 na CH4 Redukce CO2 na CH4

  19. G° = –44,8kJ F420 CH3OH G° = –112,5kJ F430 (gradient protonů přes membránu) CH4 CH4 Redukce CO2 na CH4 Redukce CO2 na CH4

  20. B N C A Ni N N N D CH3–SCH2CH2SO3–+2H++2e– CH4+HSCH2CH2SO3– F430, H2 reduktáza Faktor F430

  21. – 4+ 4+ Mo Mo 6+ – + Mo Nitráto reduktáza

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