CLONING AND SEQUENCING OF A FORM-II RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE FROM THE BACTERIAL SYMBIONT OF THE HYDROTHERMAL VENT TUBEWORM RIFTIA PACHYPTILA/

The bacterial symbiont of the hydrothermal vent tubeworm fixes carbon via the Calvin-Benson cycle and has been shown previously to express a form II ribulose-1,5-hisphosphate carboxylase/oxygenase (RubisCO). Th e gene cbbM, which encodes this enzyme, has been cloned and sequenced. The gene has the highest identity with the cbbM gene from Rhodospiril lum rubrum, and analysis of the inferred amino acid sequence reveals t hat all active-site residues are conserved. This is the first form II RubisCO cloned and sequenced from a chemoautotrophic symbiont and from a deep-sea organism.