Disorder as a novel determinant of photosynthetic structure and function: an experimental study. Australia enjoys a world reputation in photosynthesis research, typified by hosting the 2001 International Photosynthesis Congress. It also has a claim to fame for theoretical work in non-equilibrium thermodynamics concerning production of disorder or entropy, yielding new insights into planetary climates. This experimental project investigates the novel relation between entropy/entropy production ....Disorder as a novel determinant of photosynthetic structure and function: an experimental study. Australia enjoys a world reputation in photosynthesis research, typified by hosting the 2001 International Photosynthesis Congress. It also has a claim to fame for theoretical work in non-equilibrium thermodynamics concerning production of disorder or entropy, yielding new insights into planetary climates. This experimental project investigates the novel relation between entropy/entropy production and the structure/function of the solar powerhouse of plants (chloroplasts), and addresses fundamental questions at the interface of biology and physics. The research explores chloroplasts as a manifestation of the all-pervading Second Law of Thermodynamics, advancing Australia's contribution to basic science and helping to train researchers.Read moreRead less
Molecular analysis of photosynthetically-linked, active CO2 uptake and CO2 signal transduction by cyanobacteria (blue-green algae). Cyanobacteria (blue-green algae) have evolved a very efficient means of capturing and concentrating CO2 for photosynthetic fixation into sugars, the basic building blocks for cell growth. This process is dependent on the operation of several unique, active uptake systems for CO2 and HCO3-, with their genetic expression regulated by CO2 supply. This proposal will cap ....Molecular analysis of photosynthetically-linked, active CO2 uptake and CO2 signal transduction by cyanobacteria (blue-green algae). Cyanobacteria (blue-green algae) have evolved a very efficient means of capturing and concentrating CO2 for photosynthetic fixation into sugars, the basic building blocks for cell growth. This process is dependent on the operation of several unique, active uptake systems for CO2 and HCO3-, with their genetic expression regulated by CO2 supply. This proposal will capitalize on our progress in describing the functional genetics of this process and aims to elucidate the mechanism of active CO2 uptake and the way that cells sense the ambient CO2 concentration. The information gained is likely to be useful for designing improved crops.Read moreRead less
Realistic models of permeation in ion channels. Ion channels are formed by proteins in cell membranes and provide pathways for fast and controlled flow of selected ions. This activity generates action potentials in nerves and muscles that forms the basis of all movement, sensation and thought processes. Recent determination of the crystal structure of channel proteins has enabled construction of models that can relate channel function to its structure--necessary for understanding their operati ....Realistic models of permeation in ion channels. Ion channels are formed by proteins in cell membranes and provide pathways for fast and controlled flow of selected ions. This activity generates action potentials in nerves and muscles that forms the basis of all movement, sensation and thought processes. Recent determination of the crystal structure of channel proteins has enabled construction of models that can relate channel function to its structure--necessary for understanding their operation and seeking cures for diseases caused by their malfunction. This project aims to develop accurate ion-protein-water interactions for permeation models based on stochastic and molecular dynamics simulations using both classical and quantum mechanical methods.Read moreRead less
What limits CO2 diffusion inside leaves? Dissecting the diffusion path with Arabidopsis mutants. Human induced increase in atmospheric carbon dioxide is now generally accepted as contributing to global warming. Forecasting our future impact relies on models of terrestrial photosynthesis which use a signature in the atmosphere created by plants when they discriminate against the heavy stable isotope of carbon during photosynthesis. Discrimination between isotopes is affected by carbon dioxide dif ....What limits CO2 diffusion inside leaves? Dissecting the diffusion path with Arabidopsis mutants. Human induced increase in atmospheric carbon dioxide is now generally accepted as contributing to global warming. Forecasting our future impact relies on models of terrestrial photosynthesis which use a signature in the atmosphere created by plants when they discriminate against the heavy stable isotope of carbon during photosynthesis. Discrimination between isotopes is affected by carbon dioxide diffusion within leaves and key steps in this process will be identified through the use of Arabidopsis mutants. Better representation of this process in models will improve estimates of terrestrial photosynthesis and climate change forecastsRead moreRead less
Structure and function of heterodimeric amino acid transporters. Recently a new family of amino acid transporters has been identified, the members of which are involved in the delivery of amino acids between cells and tissues. All members display a rather unusual structure in that they require two subunits to be functional. The main aim of this study is to investigate the interaction between large and small subunits. The study will give insight how membrane proteins form complexes in the membran ....Structure and function of heterodimeric amino acid transporters. Recently a new family of amino acid transporters has been identified, the members of which are involved in the delivery of amino acids between cells and tissues. All members display a rather unusual structure in that they require two subunits to be functional. The main aim of this study is to investigate the interaction between large and small subunits. The study will give insight how membrane proteins form complexes in the membrane and how these interactions affect the function of a complex membrane protein.Read moreRead less
ARC Centre of Excellence - Coherent X-ray Science. The twenty first century is said to be the century of biology. And there is no doubt that the development of our understanding of biological system is continuing at a massive rate. However as our understanding deepens, we need to draw on the whole range of scientific disciplines to proceed. This Centre draws together a multidisciplinary team of world-leading scientists to address one the key questions in modern biology, the structure of a membra ....ARC Centre of Excellence - Coherent X-ray Science. The twenty first century is said to be the century of biology. And there is no doubt that the development of our understanding of biological system is continuing at a massive rate. However as our understanding deepens, we need to draw on the whole range of scientific disciplines to proceed. This Centre draws together a multidisciplinary team of world-leading scientists to address one the key questions in modern biology, the structure of a membrane protein. We will develop techniques based on the latest developments in theoretical physics & chemistry, imaging, biology and technology - including the new Australian Synchrotron - to create new approaches to structural biology.Read moreRead less
Probing the four photosynthetic membrane protein complexes at work in situ in leaves. This proposal aims at sustainable improvements in plant productivity and photosynthetic adaptation in drastic Australian climates. In photosynthesis, membranes with the four multiprotein complexes use sunlight to make compounds that drive carbon assimilation. Instead of the usual dissection of photosynthetic membranes, this project will develop and refine the applicant's rapid, reliable, non-intrusive technique ....Probing the four photosynthetic membrane protein complexes at work in situ in leaves. This proposal aims at sustainable improvements in plant productivity and photosynthetic adaptation in drastic Australian climates. In photosynthesis, membranes with the four multiprotein complexes use sunlight to make compounds that drive carbon assimilation. Instead of the usual dissection of photosynthetic membranes, this project will develop and refine the applicant's rapid, reliable, non-intrusive techniques to probe the four membrane complexes at work in their native state in leaves. Two portable commercial instruments will potentially emerge from the techniques. This novel non-reductionist approach will identify key limitations to photosynthetic performance under stress, and insights into improvements for primary plant productivity.Read moreRead less
Molecular and Cellular Characterisations of the Cortical Actin Cytoskeleton in the Plant Arabidopsis thaliana. Plant cells contain extensive arrays of the cytoskeletal protein actin that attach to the plasma membrane and may play important roles in cell elongation through interactions with cortical microtubules. However, the organisation, dynamics and functions of cortical actin remain poorly understood. I will combine cell and molecular approaches to understanding cortical actin in living tissu ....Molecular and Cellular Characterisations of the Cortical Actin Cytoskeleton in the Plant Arabidopsis thaliana. Plant cells contain extensive arrays of the cytoskeletal protein actin that attach to the plasma membrane and may play important roles in cell elongation through interactions with cortical microtubules. However, the organisation, dynamics and functions of cortical actin remain poorly understood. I will combine cell and molecular approaches to understanding cortical actin in living tissue of Arabidopsis, using both wild-type and previously uncharacterised mutants, and will develop a novel mutational screening strategy to isolate mutants disrupted in plasma membrane or microtubule binding. This research will contribute significantly to a greater understanding of how the plant grows and develops.Read moreRead less
ION CHANNELS FORMED BY SMALL PROTEINS FROM VIRUSES. Movements of ions across cell membranes through protein ion channels are essential for normal cell function. We have found that some small proteins from viruses can form ion channels. Studying these simple channels should give us clues about the function of more complex channels, such as those in the brain, as well as giving us information about the viruses themselves. We will test whether a small protein from Ross River virus forms ion channel ....ION CHANNELS FORMED BY SMALL PROTEINS FROM VIRUSES. Movements of ions across cell membranes through protein ion channels are essential for normal cell function. We have found that some small proteins from viruses can form ion channels. Studying these simple channels should give us clues about the function of more complex channels, such as those in the brain, as well as giving us information about the viruses themselves. We will test whether a small protein from Ross River virus forms ion channels and will also test the effects of selected mutations in proteins from influenza and AIDS viruses that we have shown previously to form ion channels.Read moreRead less
Hierarchical modeling of protein interactions. Protein interactions play a central role in function and structural organization of cells. Their elucidation is essential for a better understanding of many cellular processes from signal transduction to enzyme inhibition. The aim of this project is to utilize the unprecedented powers of current supercomputers in developing a hierarchical model of protein interactions. The method combines Brownian dynamics at large distances and long time scales ....Hierarchical modeling of protein interactions. Protein interactions play a central role in function and structural organization of cells. Their elucidation is essential for a better understanding of many cellular processes from signal transduction to enzyme inhibition. The aim of this project is to utilize the unprecedented powers of current supercomputers in developing a hierarchical model of protein interactions. The method combines Brownian dynamics at large distances and long time scales with molecular dynamics at small distances and shorter times. Applications to both membrane proteins (blocking of ion channels by toxins and drugs) and globular proteins (ligand binding to receptors and protein association) will be considered.Read moreRead less