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Formation of a Cross-Linking Complex of Dinitrogenase Reductase-Activating Glycohydrolase (DRAG) with Membrane Proteins from Rhodospirillum rubrum Chromatophores

N. Akentieva

Washington University in Saint Louis, 660 South Euclid Ave., Campus Box 8054, Saint Louis, MO, 63110, USA; fax: (314) 362-8571; E-mail: akentevan@morpheus.wustl.edu; na_aken@mail.ru

Received March 2, 2007; Revision received June 29, 2007
Association of dinitrogenase reductase-activating glycohydrolase (DRAG) with membrane proteins of chromatophores has been investigated. The formation of a multicomponent complex between DRAG and membrane proteins was demonstrated in the presence of glutaraldehyde and EDC/NHS (N-(3-dimethylaminopropyl)-N´-ethylcarbodiimide hydrochloride/hydroxy-2,5-dioxopyrrolidine-3-sulfonic acid sodium salt). Complex formation was observed both in native chromatophore membrane and in chromatophores treated with 0.5 M NaCl in the presence of homogeneous DRAG and glutaraldehyde in cross-reaction. The molecular weight of the complex was around 200 kD, which is consistent with the association of DRAG with three or more chromatophore membrane proteins. A specific complex with molecular weight of about 75 kD was formed only in the presence of EDC/NHS in the cross-linking reaction. It was demonstrated that ammonium transport protein and P11 protein are possible candidates for association with DRAG in chromatophore membranes.
KEY WORDS: nitrogen fixation, nitrogenase, dinitrogenase reductase-activating glycohydrolase, cross-linking complex, membranes

DOI: 10.1134/S0006297908020089