Understanding mechanistic and systemic regulation of protein prenyltransferases. The proposed research will expand our understanding of lipid-conjugating enzymes that are critical for a multitude of normal cellular functions. We seek to reveal the basic workings of cells and help to explain the development and complexity of signalling networks in eukaryotic evolution. The findings will enable us to explore and exploit the catalytic properties of these lipid-related enzymes for applications in bi ....Understanding mechanistic and systemic regulation of protein prenyltransferases. The proposed research will expand our understanding of lipid-conjugating enzymes that are critical for a multitude of normal cellular functions. We seek to reveal the basic workings of cells and help to explain the development and complexity of signalling networks in eukaryotic evolution. The findings will enable us to explore and exploit the catalytic properties of these lipid-related enzymes for applications in biotechnology. The ultimate aim is to create novel technologies for protein production, modification and analysis that will accelerate the pace of discovery in protein research, basic cell and organism biology, diagnostics, biotechnology and drug discovery. Read moreRead less
Can efficient algal variants of the photosynthetic CO2-fixing enzyme, Rubisco, be folded and assembled in functional forms in higher-plant plastids? We have shown that it is possible to alter the photosynthetic phenotype of a plant predictably and profoundly by engineering the plastid genome to replace the plant's CO2-fixing enzyme, Rubisco, with a bacterial homolog. Thus it may be possible to replace the plant enzyme with more efficient algal Rubiscos that would allow plants to grow with less l ....Can efficient algal variants of the photosynthetic CO2-fixing enzyme, Rubisco, be folded and assembled in functional forms in higher-plant plastids? We have shown that it is possible to alter the photosynthetic phenotype of a plant predictably and profoundly by engineering the plastid genome to replace the plant's CO2-fixing enzyme, Rubisco, with a bacterial homolog. Thus it may be possible to replace the plant enzyme with more efficient algal Rubiscos that would allow plants to grow with less light, less water or less fertiliser. Before such desirable changes to the plant phenotype can be realised, some complex issues of modification, folding and assembly of Rubisco subunits need to be resolved. This proposal addresses them.Read moreRead less
Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzy ....Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzyme. This project describes the biochemical characterisation of specific enzyme activities within microcystin synthetase and how they determine the final structure and toxicity of the many forms of microcystin. Interactions between this enzyme complex and its substrate amino acids will provide information for the genetic engineering of this and similar natural products.Read moreRead less
Zinc finger domains as scaffolds for protein engineering. While great advances have been made in pharmaceutical design and discovery, it is clear that new types of drugs are needed for the better management of a wide range of diseases (e.g. cancers, autoimmune diseases, viral infections). Many of these diseases arise from inappropriate interactions between intracellular biological macromolecules. My aim is to develop a range of novel therapeutic proteins based on naturally existing zinc-binding ....Zinc finger domains as scaffolds for protein engineering. While great advances have been made in pharmaceutical design and discovery, it is clear that new types of drugs are needed for the better management of a wide range of diseases (e.g. cancers, autoimmune diseases, viral infections). Many of these diseases arise from inappropriate interactions between intracellular biological macromolecules. My aim is to develop a range of novel therapeutic proteins based on naturally existing zinc-binding protein domains with the goal of selectively blocking these inappropriate interactions. Additionally, these engineered proteins have potential uses as biochemical tools such as to help delineate the functions of natural proteins with no known functions.Read moreRead less
Assembly and function of arabinogalactan-proteins: a class of proteoglycans involved in plant growth and development. We aim to define the mechanisms by which a family of cell surface proteoglycans, the arabinogalactan-proteins (AGPs), are assembled and contribute to the regulation of plant growth and development using Arabidopsis, a model system amenable to a functional genomics strategy. This will be achieved through the application of bioinformatics for gene discovery and molecular, biochemi ....Assembly and function of arabinogalactan-proteins: a class of proteoglycans involved in plant growth and development. We aim to define the mechanisms by which a family of cell surface proteoglycans, the arabinogalactan-proteins (AGPs), are assembled and contribute to the regulation of plant growth and development using Arabidopsis, a model system amenable to a functional genomics strategy. This will be achieved through the application of bioinformatics for gene discovery and molecular, biochemical and genetics approaches to define gene function. Understanding mechanisms that control plant growth and development will ultimately impact on industries (agriculture, horticulture and forestry) vital to Australia's prosperity.Read moreRead less
Assembly and function of arabinogalactan-proteins: a class of proteoglycans involved in plant growth and development. Achievements of the Objectives will specifically address National Research Priority 3 by developing breakthrough science and utilising frontier technologies with application to Australia's agri-biotechnology industries. In addition to contributing to world class research outcomes, we will train highly skilled graduates and postdoctoral fellows in functional genomics technologies, ....Assembly and function of arabinogalactan-proteins: a class of proteoglycans involved in plant growth and development. Achievements of the Objectives will specifically address National Research Priority 3 by developing breakthrough science and utilising frontier technologies with application to Australia's agri-biotechnology industries. In addition to contributing to world class research outcomes, we will train highly skilled graduates and postdoctoral fellows in functional genomics technologies, thereby contributing to the "knowledge nation".Read moreRead less
Practical strategies for engineering the CO2-fixing enzyme, Rubisco, whose subunits are encoded in different subcellular compartments. My recent replacement of the plant CO2-fixing enzyme, Rubisco, with a less efficient bacterial version, with a single type of subunit encoded by a single gene, demonstrated the feasibility of replacing Rubisco. This encourages ongoing attempts to replace plant Rubisco with more efficient versions that would allow the plants to grow with less water, fertiliser or ....Practical strategies for engineering the CO2-fixing enzyme, Rubisco, whose subunits are encoded in different subcellular compartments. My recent replacement of the plant CO2-fixing enzyme, Rubisco, with a less efficient bacterial version, with a single type of subunit encoded by a single gene, demonstrated the feasibility of replacing Rubisco. This encourages ongoing attempts to replace plant Rubisco with more efficient versions that would allow the plants to grow with less water, fertiliser or light. The most efficient Rubiscos are more complex, with two different types of subunits which, in plants, are encoded in different subcellular compartments (nucleus and plastid). This proposal addresses the challenges associated with complementary engineering both genomes to substitute foreign Rubiscos into higher-plant chloroplasts.Read moreRead less
Controlling the rate of transcription and translation of Rubisco transgenes effectively in higher-plant plastids. Genetic transformation of the circular genome of the plastids provides a containable means for modifying plant growth by manipulating photosynthesis. Although the transformation mechanism is precise, predicting the level of foreign gene expression is difficult because the amounts of messenger RNA and protein produced by foreign genes in plastids varies widely, even when the protein a ....Controlling the rate of transcription and translation of Rubisco transgenes effectively in higher-plant plastids. Genetic transformation of the circular genome of the plastids provides a containable means for modifying plant growth by manipulating photosynthesis. Although the transformation mechanism is precise, predicting the level of foreign gene expression is difficult because the amounts of messenger RNA and protein produced by foreign genes in plastids varies widely, even when the protein assembles without difficulty. This project will devise strategies for controlling this variability that will facilitate attempts to exploit plastid transformation for transplanting better versions of the photosynthetic CO2-fixing enzyme, Rubisco, into plants to improve their growth efficiency in terms of water, fertiliser and light use.Read moreRead less
Identifying potential barriers to transplanting modified forms of the CO2-fixing enzyme, Rubisco, into plants. Improving the ability of crops to use water, light and fertiliser more efficiently would have economic benefits and ease the environmental impacts associated with agricultural practices. It is thought that such improvements can be made by enhancing the efficiency of the photosynthetic protein, Rubisco, which fixes most of the CO2 in the biosphere. The research proposed here uses unique ....Identifying potential barriers to transplanting modified forms of the CO2-fixing enzyme, Rubisco, into plants. Improving the ability of crops to use water, light and fertiliser more efficiently would have economic benefits and ease the environmental impacts associated with agricultural practices. It is thought that such improvements can be made by enhancing the efficiency of the photosynthetic protein, Rubisco, which fixes most of the CO2 in the biosphere. The research proposed here uses unique Rubisco transplantation capabilities that I have developed to improve our fundamental understanding of how Rubisco is processed and its activity regulated in plants. This will pave the way for our ongoing efforts to engineer and transplant more efficient Rubisco into crops.Read moreRead less
The structure and function of cyanobacterial carboxysome multi-protein complexes and their role in carbon sequestration in cyanobacteria. Cyanobacteria are important contributors to global photosynthesis and have evolved unique mechanisms for capturing CO2 from their aquatic environments. Understanding these molecular mechanisms is important for both predicting how cyanobacteria affect carbon fixation at the global scale, and how their genetic specialisation may be used for improving photosynthe ....The structure and function of cyanobacterial carboxysome multi-protein complexes and their role in carbon sequestration in cyanobacteria. Cyanobacteria are important contributors to global photosynthesis and have evolved unique mechanisms for capturing CO2 from their aquatic environments. Understanding these molecular mechanisms is important for both predicting how cyanobacteria affect carbon fixation at the global scale, and how their genetic specialisation may be used for improving photosynthesis in agricultural plants. This project aims to examine one particular aspect of this specialisation, the multi-protein carboxysome complex, where CO2 fixation occurs. Using recent whole-genome information we will take a proteogenomic approach to understanding the structure and function of the carboxysome and how it contributes to the photosynthesis of the cell.Read moreRead less