Immunolocalization of the uptake hydrogenase in cyanobacteria

In N2-fixing cyanobacteria the reduction of N2 to NH3§is coupled §with the production of molecular hydrogen (H2), which§is rapidly §consumed by an uptake hydrogenase, an enzyme that is§present in §almost all the diazotrophic cyanobacteria. The§cellular and sub-§cellular localization of the cyanobacterial uptake§hydrogenase §remains unclear, and the previously available data§focuses mainly on §heterocystous cyanobacteria.§In this work the localization of the uptake§hydrogenase in Lyngbya §majuscula CCAP 1446/4, a non-heterocystous§cyanobacterium, was §investigated. The data obtained revealed higher§specific labelling §associated with the thylakoid membranes of L. majuscula. §Additionally, a comparative analysis was performed§using a §unicellular - Gloeothece sp. ATCC 27152, and two§heterocystous §strains - Nostoc sp. PCC 7120 and Nostoc punctiforme§PCC 73102. §No labelling was found on the vegetative cells of§Nostoc sp. PCC §7120, in contrast with the situation in N.§punctiforme, in which §labelling was detected in both vegetative cells and§heterocysts.§The results presented in this work will contribute to§a better §understanding of the field of H2 metabolism in§cyanobacteria.