Cellular Biochemistry of Carbon dioxide Fixation


Global biomass production relies on the function of the key photosynthetic enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). Paradoxically, this enzyme is slow and catalyzes a metabolite damaging side-reaction with molecular oxygen. Our laboratory aims to understand how a wide diversity of organisms, such as plants, cyanobacteria and algae, have dealt with the conserved suboptimal properties of this catalyst. Our tools focus on mechanistic biochemistry, with an emphasis on bottom-up reconstitution. We supplement this core expertise with complementary approaches such as structural, cell and molecular biology tools to follow questions of interest.

Currently strong research themes in the group include mechanistic studies of diverse Rubisco activases, molecular motors of the AAA+ ATPase class. We also study the formation of Rubisco containing biomolecular condensates via liquid liquid phase separation, a key strategy of CO2 concentrating mechanisms.

Oliver Martin Mueller-Cajar
Oliver Martin Mueller-Cajar
Associate Professor

Email: cajar@ntu.edu.sg
Phone: (65) 6592 3184
Office: SBS-02S-88D
Lab webpage
Alexander Schober
Research Fellow

Email: alexander.schober@ntu.edu.sg
How Jian Ann
Research Fellow

Email: jhow004@e.ntu.edu.sg
Tsai Yi-Chin Candace
Senior Research Fellow

Email: yichin.tsai@ntu.edu.sg
Guo ZhiJun
Research Fellow

Email: zhijun.guo@ntu.edu.sg
Pooja Ragunathan
Research Assistant

Email: poojaa.ragunathan@ntu.edu.sg
How Jian Boon
PhD Student

Email: HOWJ0005@e.ntu.edu.sg
Ng Yi Siang
PhD Student

Email: ngyi0035@e.ntu.edu.sg
Poh Cheng Wei
PhD Student

Email: chengwei002@e.ntu.edu.sg
Warren Ang Shou Leng
PhD Student

Email: warr0004@e.ntu.edu.sg


  • Exploration and Utilization of the Natural Diversity of Rubisco Regulators
    This project concerns the structural and biochemical characterization of the molecular chaperones known as Rubisco activases (Rca). Three convergently evolved Rca systems have been discovered but function via diverse mechanisms.
  • Integrating in vivo and in vitro Approaches for Metagenomic RuBisCO Sequence Mining to Improve Carbon Fixation​
    In collaboration with the group of Prof. Ron Milo (Weizmann Institute of Science), we are characterizing novel Rubisco enzymes.
  • Reconstituting Phase Separations that Enable the Microalgal CO2 Superchargers
    ​Biophysical carbon concentrating mechanisms require Rubisco to be sequestered at high concentration in microcompartments. We are reconstituting these events in vitro, and have found them to be related to the concept of liquid liquid phase separation.
  • The Unusual CO2-fixing Engine of Dinoflagellates, the Algae that Powers the Coral Ecosystems
    The endosymbionts of corals possess Rubisco enzymes that resemble those of prokaryotes. We are characterizing the structure and biochemistry of these catalysts
Full list of publications can be found here
  • **Tsai YC, Ye F, **Liew L, *Liu D, Bhushan S, Gao YG, Mueller-Cajar O. Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase. Proc Natl Acad Sci U S A. 117(1) 381-387, 2020##
  • **Shivhare D, *Ng, J, **Tsai YC, Mueller-Cajar O. Probing the rice Rubisco-Rubisco activase interaction via subunit heterooligomerization. Proc Natl Acad Sci U S A. 116(48) 24041-24048, 2019##
  • Atkinson N, Velanis CN, **Wunder T, Clarke DJ, Mueller-Cajar O, McCormick AJ. The pyrenoidal linker protein EPYC1 phase separates with hybrid ArabidopsisChlamydomonas Rubisco through interactions with the algal Rubisco small subunit. J Exp Bot 70(19):5271-5285, 2019##
  • **Wunder T, *Oh ZG, Mueller-Cajar O. CO2-fixing liquid droplets: Towards a dissection of the microalgal pyrenoid. Traffic 20(6):380-389, 2019#
  • ·**Wunder T, **Cheng SLH, Lai SK, Li HY, Mueller-Cajar O. The phase separation underlying the pyrenoid-based microalgal Rubisco supercharger. Nat. Commun. 9(1):5076, 2018##
  • Bhat JY, Miličić G, Thieulin-Pardo G, Bracher A, Maxwell A, Ciniawsky S, Mueller-Cajar O, Engen JR, Hartl FU, Wendler P, Hayer-Hartl M., Mechanism of Enzyme Repair by the AAA(+) Chaperone Rubisco Activase. Mol Cell. 67(5):744-756, 2017##
  • *Liu D, *Ramya RCS, Mueller-Cajar O., Surveying the expanding prokaryotic Rubisco multiverse. FEMS Microbiol Lett. 364(16), 2017
  • Mueller-Cajar O., The diverse AAA+ Machines that Repair inhibited Rubisco Active Sites. Front Mol Biosci. 4:31, 2017
  • *Shivhare D, Mueller-Cajar O., In vitro characterization of thermostable CAM Rubisco activase reveals a Rubisco interacting surface loop. Plant Physiol. 174(3):1505-1516, 2017##
  • *Loganathan N, **Tsai YC, Mueller-Cajar O., Characterization of the heterooligomeric red-type rubisco activase from red algae. Proc Natl Acad Sci U S A. 113(49):14019-14024, 2016##