Stoichiometry of ATP hydrolysis and chlorophyllide formation of dark-operative protochlorophyllide oxidoreductase from Rhodobacter capsulatus.
Biochem Biophys Res Commun
; 470(3): 704-709, 2016 Feb 12.
Article
em En
| MEDLINE
| ID: mdl-26774340
ABSTRACT
Dark-operative protochlorophyllide (Pchlide) oxidoreductase (DPOR) is a nitrogenase-like enzyme catalyzing a reduction of the C17 = C18 double bond of Pchlide to form chlorophyllide a (Chlide) in bacteriochlorophyll biosynthesis. DPOR consists of an ATP-dependent reductase component, L-protein (a BchL dimer), and a catalytic component, NB-protein (a BchN-BchB heterotetramer). The L-protein transfers electrons to the NB-protein to reduce Pchlide, which is coupled with ATP hydrolysis. Here we determined the stoichiometry of ATP hydrolysis and the Chlide formation of DPOR. The minimal ratio of ATP to Chlide (ATP/2e(-)) was 4, which coincides with that of nitrogenase. The ratio increases with increasing molar ratio of L-protein to NB-protein. This profile differs from that of nitrogenase. These results suggest that DPOR has a specific intrinsic property, while retaining the common features shared with nitrogenase.
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MEDLINE
Assunto principal:
Trifosfato de Adenosina
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Clorofilídeos
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Rhodobacter capsulatus
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Oxirredutases atuantes sobre Doadores de Grupo CH-CH
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article