Modeling the membrane potential generation of bacteriorhodopsin.
Math Biosci
; 225(1): 68-80, 2010 May.
Article
en En
| MEDLINE
| ID: mdl-20188746
ABSTRACT
The archaeon Halobacterium salinarum can grow phototrophically with only light as its energy source. It uses the retinal containing and light-driven proton pump bacteriorhodopsin to enhance the membrane potential which drives the ATP synthase. Therefore, a model of the membrane potential generation of bacteriorhodopsin is of central importance to the development of a mathematical model of the bioenergetics of H. salinarum. To measure the current produced by bacteriorhodopsin at different light intensities and clamped voltages, we expressed the gene in Xenopus laevis oocytes. We present current-voltage measurements and a mathematical model of the current-voltage relationship of bacteriorhodopsin and its generation of the membrane potential. The model consists of three intermediate states, the BR, L, and M states, and comparisons between model predictions and experimental data show that the L to M reaction must be inhibited by the membrane potential. The model is not able to fit the current-voltage measurements when only the M to BR phase is membrane potential dependent, while it is able to do so when either only the L to M reaction or both reactions (L to M and M to BR) are membrane potential dependent. We also show that a decay term is necessary for modeling the rate of change of the membrane potential.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Bacteriorodopsinas
/
Halobacterium salinarum
/
Potenciales de la Membrana
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Modelos Biológicos
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Math Biosci
Año:
2010
Tipo del documento:
Article
País de afiliación:
Alemania