CE20 - Biologie des animaux, des organismes photosynthétiques et des microorganismes

iota Carbonic Anhydrase: A key response to CO2 in diatoms – OCEANIA

Submission summary

We recently discovered a protein from the model marine diatom, Thalassiosira pseudonana, that belongs to a new subclass of carbonic anhydrase, iota-CA. We showed that this protein is involved in CO2-concentrating mechanisms and uses Mn2+ as a co-factor instead of Zn2+. Since we also showed that iota-CA is present in other marine diatoms and is widespread in the ocean, it could have a significant role in global biogeochemical cycling. The use of Mn2+ instead of Zn2+ may reflect its availability or affect the enzyme properties. The overarching scientific objective of this project is to elucidate the role of iota-CA in photosynthesis of marine diatoms, extending the analysis to a contrasting diatom, Phaeodactylum tricornutum, where the use of genetic tools are better established. This objective will be achieved within 3 workpackages combining a range of in vitro and in vivo methods. The aim of workpackage 1 is to unravel the detailed molecular mechanisms of the function, and architecture of iota-CA from the information yielded by its protein structure using a combination of structural, biophysical and biochemical methods. The aim of workpackage 2 is to elucidate the catalytic mechanisms of iota-CA, and the role of Mn2+ instead of Zn2+. The aim of the third workpackage is to determine the effect of iota-CA inactivation on diatoms growth and physiology using genetic engineering tools and proteomic analyses, to determine the contribution of iota-CA to the metabolism of the diatoms.

Project coordination

Véronique RECEVEUR-BRECHOT (Bioénergétique et ingénierie des protéines)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


IMM Institut de Microbiologie de la Méditerranée
BIP Bioénergétique et ingénierie des protéines
LBI2M Laboratoire de Biologie intégrative des modèles marins

Help of the ANR 340,415 euros
Beginning and duration of the scientific project: February 2022 - 42 Months

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