Sellstedt A, Mattsson U
Hydrogen Metabolism in Casuarina-Frankia - Immunolocalization of Nitrogenase and Hydrogenase
Soil Biology & Biochemistry: 1994 26:583-592
Enzymes involved in hydrogen metabolism were immunologically investigated for occurrence and localization. Western immunoblots on free-living and symbiotic Frankia KB revealed that a 36 kDa protein found both in symbiotic and free-living Frankia was immunologically related to the Fe-protein of nitrogenase purified from Rhodospirillum rubrum. Also, a 63 kDa protein immunologically related to the large subunit of a dimeric hydrogenase from Alcaligenes latus was found in free-living Frankia KB. Reversible hydrogenase could not be detected. The Fe-protein of nitrogenase was present in hyphae of the symbiotic association, as demonstrated by use of immunogold localization. Vesicles could not be observed in the symbiosis between Casuarina and Frankia. It is apparent that differentiation of vesicles is not necessary for having an active nitrogenase. In free-living Frankia grown without nitrogen, it was shown that nitrogenase was mainly localized in vesicles. Uptake hydrogenase was present mainly in vesicles, but to some extent also in hyphae of free-living Frankia KB. Reversible hydrogenase could not be detected in symbiotic nor in free-living Frankia.
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