Isolation and Oligomeric Composition of Cytochrome c Nitrite Reductase from the Haloalkaliphilic Bacterium Thioalkalivibrio nitratireducens

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T. V. Tikhonova^1*, E. S. Slutskaya¹, A. A. Filimonenkov¹, K. M. Boyko¹, S. Yu. Kleimenov¹, P. V. Konarev^2,3, K. M. Polyakov⁴, D. I. Svergun^2,3, A. A. Trofimov⁴, V. G. Khomenkov¹, R. A. Zvyagilskaya¹, and V. O. Popov¹

¹Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia; fax: (495) 954-2732; E-mail: ttikhonova@inbi.ras.ru

²Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 119333 Moscow, Russia; fax: (495) 135-1011

³European Molecular Biology Laboratory (EMBL), Hamburg, Germany

⁴Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, 119991 Moscow, Russia; fax: (495) 135-1405

^* To whom correspondence should be addressed.

Received July 5, 2007; Revision received August 27, 2007

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A new procedure for isolation of cytochrome c nitrite reductase from the haloalkaliphilic bacterium Thioalkalivibrio nitratireducens increasing significantly the yield of the purified enzyme is presented. The enzyme is isolated from the soluble fraction of the cell extract as a hexamer, as shown by gel filtration chromatography and small angle X-ray scattering analysis. Thermostability of the hexameric form of the nitrite reductase is characterized in terms of thermoinactivation and thermodenaturation.

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KEY WORDS: cytochrome c nitrite reductase, isolation, oligomeric composition, thermostability, thermodenaturation

DOI: 10.1134/S0006297908020077

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