Archives of Microbiology

, Volume 182, Issue 1, pp 18–29

Characterization and expression of genes from the RubisCO gene cluster of the chemoautotrophic symbiont of Solemya velum: cbbLSQO

Authors

  • Julie Schwedock
    • Department of Organismic and Evolutionary BiologyHarvard University
    • Genomic Profiling Systems
  • Tara L. Harmer
    • Department of Organismic and Evolutionary BiologyHarvard University
  • Kathleen M. Scott
    • Department of Organismic and Evolutionary BiologyHarvard University
    • Department of BiologyUniversity of South Florida
  • Harm J. Hektor
    • Department of Organismic and Evolutionary BiologyHarvard University
  • Angelica P. Seitz
    • Department of Organismic and Evolutionary BiologyHarvard University
  • Matthew C. Fontana
    • Department of Organismic and Evolutionary BiologyHarvard University
  • Daniel L. Distel
    • Department of Organismic and Evolutionary BiologyHarvard University
    • Department of Biochemistry, Microbiology, and Molecular BiologyUniversity of Maine
    • Department of Organismic and Evolutionary BiologyHarvard University
Original Paper

DOI: 10.1007/s00203-004-0689-x

Cite this article as:
Schwedock, J., Harmer, T.L., Scott, K.M. et al. Arch Microbiol (2004) 182: 18. doi:10.1007/s00203-004-0689-x

Abstract

Chemoautotrophic endosymbionts residing in Solemya velum gills provide this shallow water clam with most of its nutritional requirements. The cbb gene cluster of the S. velum symbiont, including cbbL and cbbS, which encode the large and small subunits of the carbon-fixing enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), was cloned and expressed in Escherichia coli. The recombinant RubisCO had a high specific activity, ∼3 μmol min−1 mg protein −1, and a KCO2 of 40.3 μM. Based on sequence identity and phylogenetic analyses, these genes encode a form IA RubisCO, both subunits of which are closely related to those of the symbiont of the deep-sea hydrothermal vent gastropod Alviniconcha hessleri and the photosynthetic bacterium Allochromatium vinosum. In the cbb gene cluster of the S. velum symbiont, the cbbLS genes were followed by cbbQ and cbbO, which are found in some but not all cbb gene clusters and whose products are implicated in enhancing RubisCO activity post-translationally. cbbQ shares sequence similarity with nirQ and norQ, found in denitrification clusters of Pseudomonas stutzeri and Paracoccus denitrificans. The 3′ region of cbbO from the S. velum symbiont, like that of the three other known cbbO genes, shares similarity to the 3′ region of norD in the denitrification cluster. This is the first study to explore the cbb gene structure for a chemoautotrophic endosymbiont, which is critical both as an initial step in evaluating cbb operon structure in chemoautotrophic endosymbionts and in understanding the patterns and forces governing RubisCO evolution and physiology.

Keywords

RubisCOSymbiosisChemosynthesisSolemya velumRibulose 1,5-bisphosphate carboxylase/oxygenaseKCO2

Copyright information

© Springer-Verlag 2004