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The Membrane-Bound Quinohemoprotein Alcohol Dehydrogenase from Gluconacetobacter diazotrophicus PAL5 Carries a [2Fe-2S] Cluster

The Membrane-Bound Quinohemoprotein Alcohol Dehydrogenase from Gluconacetobacter diazotrophicus PAL5 Carries a [2Fe-2S] Cluster

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GÓMEZ-MANZO, Saúl, Alejandro SOLANO-PERALTA, Juan Pablo SAUCEDO-VÁZQUEZ, J. Edgardo ESCAMILLA-MARVÁN, Peter M. H. KRONECK, Martha Elena SOSA-TORRES, 2010. The Membrane-Bound Quinohemoprotein Alcohol Dehydrogenase from Gluconacetobacter diazotrophicus PAL5 Carries a [2Fe-2S] Cluster. In: Biochemistry. 49(11), pp. 2409-2415. ISSN 0006-2960. eISSN 1520-4995

@article{Gomez-Manzo2010-03-23Membr-37641, title={The Membrane-Bound Quinohemoprotein Alcohol Dehydrogenase from Gluconacetobacter diazotrophicus PAL5 Carries a [2Fe-2S] Cluster}, year={2010}, doi={10.1021/bi9015007}, number={11}, volume={49}, issn={0006-2960}, journal={Biochemistry}, pages={2409--2415}, author={Gómez-Manzo, Saúl and Solano-Peralta, Alejandro and Saucedo-Vázquez, Juan Pablo and Escamilla-Marván, J. Edgardo and Kroneck, Peter M. H. and Sosa-Torres, Martha Elena} }

Escamilla-Marván, J. Edgardo Saucedo-Vázquez, Juan Pablo Kroneck, Peter M. H. 2017-02-21T13:36:21Z 2017-02-21T13:36:21Z Sosa-Torres, Martha Elena Escamilla-Marván, J. Edgardo The Membrane-Bound Quinohemoprotein Alcohol Dehydrogenase from Gluconacetobacter diazotrophicus PAL5 Carries a [2Fe-2S] Cluster Sosa-Torres, Martha Elena Gluconacetobacter diazotrophicus stands out among the acetic acid bacteria as it fixes dinitrogen and is a true endophyte. It has a set of constitutive enzymes to oxidize ethanol and acetaldehyde which is upregulated during N<sub>2</sub>-dependent growth. The membrane-bound alcohol dehydrogenase (ADH) is a heterodimer (subunit I approximately 72 kDa, subunit II approximately 44 kDa) and constitutes an important component of this organism. ADH of Ga. diazotrophicus is a typical quinohemoprotein with one pyrroloquinoline quinone (PQQ) and four c-type cytochromes. For the first time, a [2Fe-2S] cluster has been identified by EPR spectroscopy in this type of enzyme. This finding is supported by quantitative chemical analysis, revealing 5.90 +/- 0.15 Fe and 2.06 +/- 0.10 acid-labile sulfurs per ADH heterodimer. The X-band EPR spectrum of ADH (as isolated in the presence of dioxygen, 20 K) showed three broad resonances at g 2.007, 1.941, and 1.920 (g<sub>av</sub> 1.956), as well as an intense narrow line centered at g = 2.0034. The latter signal, which was still detected at 100 K, was attributed to the PQQ semiquinone radical (PQQ<sub>sq</sub>). The broad resonances observed at lower temperature were assigned to the [2Fe-2S] cluster in the one-electron reduced state. The oxidation-reduction potentials E<sub>m</sub> (pH 6.0 vs SHE) of the four c-type cytochromes were estimated to E<sub>m1</sub> = -64 (+/-2) mV, E<sub>m2</sub> = -8 (+/-2) mV, E<sub>m3</sub> = +185 (+/-15) mV, and E<sub>m4</sub> = +210 (+/-10) mV (spectroelectrochemistry), E<sub>mFeS</sub> = -250 (+/-5) mV for the [2Fe-2S] cluster, and E<sub>mPQQ</sub> = -210 (+/-5) mV for the PQQ/PQQH<sub>2</sub> couple (EPR spectroscopy). We propose a model for the membrane-bound ADH of Ga. diazotrophicus showing hypothetical intra- and intermolecular electron pathways. Subunit I binds the PQQ cofactor, the [2Fe-2S] cluster, and one c-type cytochrome. Subunit II harbors three c-type cytochromes, thus providing an efficient electron transfer route to quinones located in the cytoplasmic membrane. eng Solano-Peralta, Alejandro Kroneck, Peter M. H. Solano-Peralta, Alejandro Saucedo-Vázquez, Juan Pablo 2010-03-23 Gómez-Manzo, Saúl Gómez-Manzo, Saúl

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