We are a node of the ARC Centre of Excellence for Translational Photosynthesis. We focus on finding the far red light limit to bioconversion by studying genetic, chemical and structural adaptations that allow organisms to function under filtered light environments. Using cyanobacteria as our model organism, we look at external and internal antennae systems, chlorophylls, and other molecular regulatory components.
All oxygenic photosynthetic organisms use an antenna system to increase the efficiency of photosynthesis. In cyanobacteria and red algae, the main antenna systems are outer antenna complexes, known as phycobilisomes, which are assembled by bilin-binding protein complexes (phycobiliproteins).
We use biophysical and biochemical laboratory techniques to look at their structure and chemistry, including absorbance and fluorescence spectroscopy, mass spectrometry, peptide fingerprinting, high performance liquid chromatography, electron microscopy, as well as structural analysis using the QUOKKA instrument at ANSTO and electron microscopy through collaborations with Prof. Robert Willow at Macquarie University.
Our novel research includes describing and characterising the functions of red-shifted chlorophyll f discovered in cyanobacteria in stromatolites from Shark Bay, Western Australia. This chlorophyll was first described by Prof Min Chen in 2010; it has a unique adaptation to far-red light, which could have important agricultural potential.
We study the biochemical and biosynthetic pathways of red-shifted chlorophylls (Chl d and Chl f) using in vitro enzymatic synthesis of Chl d from Chl a, and knock-out mutants in cyanobacteria. Understanding these pathways will improve the light harvesting efficiency of economically important crops.
Light-harvesting complexes in cyanobacteria and plants have a network of pigments that collect photons and transfer light energy to reaction centres.
We study light-harvesting processes by investigating how wavelengths in different regions of light are absorbed and transferred to these reaction centres. Our study involves looking at the role of specific proteins using in vitro and in vivo laboratory methods, including cloning, protein purification in native conditions, in vitro reconstitution, and spectral analyses.
Some photosynthetic organisms use photoreceptors that detect changes in light quality, triggering a downstream physiological response. Our group focuses on photoreceptors capable of detecting photosynthetically active radiation.
We are specifically interested in phytochromes that can act as red/far-red photoreceptors. We recently identified a putative phytochrome in the marine cyanobacterium Acarychloris marina. Our work looks at the mechanisms by which this phytochrome interacts with other chromophores using spectral analyses.
Using genome and gene-level analyses, we have analysed the genome of A. marina and the newly sequenced genome of Halomicronema hongdechloris in search of unknown components in the photosynthetic pathway, including newly discovered non-protein coding RNAs (ncRNAs).
We apply state-of-the-art proteomic analyses to identify specific gene’s functions in response to changed light environments. Our main challenge involves identifying evolutionary modifications that facilitate assembly of photosynthetic complexes capable of performing photosynthesis under far-red light, including changes to light sensing complexes, specialized light-harvesting proteins, and chaperones.
For information about opportunities to work or collaborate with the Photosynthesis Lab, contact Associate Professor Min Chen via Research Supervisor Connect.
In addition, there are student opportunities available through the ARC Centre of Excellence for Translational Photosynthesis - under Education & Training.