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
MOLECULAR BREEDING OF CYTOCHROME P450 ENZYMES. Cytochrome P450s are enzymes that catalyse an impressive array of oxidative transformations. However, there is little available data on how to modify their substrate specificity and generate tailored biocatalysts. We plan to use an emerging technology known as DNA shuffling to create libraries of P450s with varying activities. These will then be screened for enzymes that can catalyse the formation of indigo (a blue dye) and indirubin (a chemother ....MOLECULAR BREEDING OF CYTOCHROME P450 ENZYMES. Cytochrome P450s are enzymes that catalyse an impressive array of oxidative transformations. However, there is little available data on how to modify their substrate specificity and generate tailored biocatalysts. We plan to use an emerging technology known as DNA shuffling to create libraries of P450s with varying activities. These will then be screened for enzymes that can catalyse the formation of indigo (a blue dye) and indirubin (a chemotherapeutic agent). The enzymes that catalyse indigo formation will be useful in the production of coloured transgenic plants and those that produce indirubin will have a role in gene therapy.Read moreRead less
Functional and structural diversity of the cathepsin L peptidase from the human blood fluke Schistosoma mansoni. Peptidases are enzymes that are important in many infectious and physiological disease states. For example, they are used by infectious pathogens to enter human tissues and survive inside their bodies. The same type of enzymes also contribute to tissue damage in many pathological processes in humans such as cancer, arithritis and osteoporosis. There is an urgent need to define their s ....Functional and structural diversity of the cathepsin L peptidase from the human blood fluke Schistosoma mansoni. Peptidases are enzymes that are important in many infectious and physiological disease states. For example, they are used by infectious pathogens to enter human tissues and survive inside their bodies. The same type of enzymes also contribute to tissue damage in many pathological processes in humans such as cancer, arithritis and osteoporosis. There is an urgent need to define their structure and properties so that we can employ rational approaches to develop new drugs that can combat these diseases and ailments. Read moreRead less
Aminopeptidases involved in regulating the amino acid pool in malaria parasites. Aminopeptidases are pivotal to the normal functions of all cells. Abnormalities in their function and/or structure results in tissue damage in many pathological processes in humans such as cancer, neuronal diseases and hormonal action. They are also critical to viral, bacterial and parasitic infections as they are employed to remove amino acids from the host for use in building their own proteins. This project bring ....Aminopeptidases involved in regulating the amino acid pool in malaria parasites. Aminopeptidases are pivotal to the normal functions of all cells. Abnormalities in their function and/or structure results in tissue damage in many pathological processes in humans such as cancer, neuronal diseases and hormonal action. They are also critical to viral, bacterial and parasitic infections as they are employed to remove amino acids from the host for use in building their own proteins. This project brings national and international expertise together to define the structure and biological properties of these essential enzymes so that in the future we can employ rational approaches to develop new drugs that can combat these diseases and ailments.Read moreRead less
Organophosphate pesticide degradation: evolved enzymes and biomimetics for bioremediation and medicine. Organophosphate (OP) pesticides are an indispensable part of modern agriculture - their use results in dramatically increased crop yields. However, they are toxic and can damage the environment and cause significant health problems. Enzymes are currently being used to treat runoff water that is contaminated with OPs. The same enzymes also have the potential to aid in the treatment of OP poison ....Organophosphate pesticide degradation: evolved enzymes and biomimetics for bioremediation and medicine. Organophosphate (OP) pesticides are an indispensable part of modern agriculture - their use results in dramatically increased crop yields. However, they are toxic and can damage the environment and cause significant health problems. Enzymes are currently being used to treat runoff water that is contaminated with OPs. The same enzymes also have the potential to aid in the treatment of OP poisoning. However, OP degrading enzymes could be improved in many ways - we will evolve these enzymes to enhance their catalytic properties - to enable them to act more efficiently on an increased number of OPs. Read moreRead less
The molecular biology and biochemistry of bacterial manganese oxidation. This project will further the understanding of bacterial manganese (Mn2+) oxidation. A multi-disciplinary approach will be used to further investigate the genetics and biochemistry of the Mn2+-oxidising systems of Pseudomonas putida, Leptothrix sp. and Pedomicrobium sp. This work will focus in particular on comparing the Mn2+-oxidising systems from unrelated bacteria. A combination of molecular biology, protein biochemis ....The molecular biology and biochemistry of bacterial manganese oxidation. This project will further the understanding of bacterial manganese (Mn2+) oxidation. A multi-disciplinary approach will be used to further investigate the genetics and biochemistry of the Mn2+-oxidising systems of Pseudomonas putida, Leptothrix sp. and Pedomicrobium sp. This work will focus in particular on comparing the Mn2+-oxidising systems from unrelated bacteria. A combination of molecular biology, protein biochemistry and spectroscopy will be used. This will be the first time that the enzymes of bacterial Mn2+-oxidation will have been characterised in such detail and will lead to a greater understanding of the process of bacterial manganese oxidation.Read moreRead less
Novel mechanisms of bacterial arsenic metabolism - arsenate reduction and arsenite oxidation. Novel arsenic metabolising bacteria (i.e., arsenate respiring and arsenite oxidising), which are both phylogenetically and physiologically unique, have been isolated from arsenic-contaminated areas in Australia. The arsenate respiring bacterium, Chrysiogenes arsenatis, is of particular interest as it is the only organism reported able to respire with arsenate using the respiratory substrate acetate as t ....Novel mechanisms of bacterial arsenic metabolism - arsenate reduction and arsenite oxidation. Novel arsenic metabolising bacteria (i.e., arsenate respiring and arsenite oxidising), which are both phylogenetically and physiologically unique, have been isolated from arsenic-contaminated areas in Australia. The arsenate respiring bacterium, Chrysiogenes arsenatis, is of particular interest as it is the only organism reported able to respire with arsenate using the respiratory substrate acetate as the electron donor. It is proposed that physiological, biochemical and molecular biological studies be carried out to better understand the mechanisms by which these organisms metabolise arsenic. The knowledge gained from these studies will have worldwide application in the development of an arsenic bioremediation system.Read moreRead less
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
Feasting on protein? Strategies of organic nitrogen acquisition by plant roots. Crops require large amounts of nitrogen for growth. Application of nitrogen fertiliser enhances yield, but causes off-site nitrogen pollution, a main threat to ecosystem integrity. Most nitrogen in soil occurs as organic complexes that are broken down by soil organism into small compounds, which are taken up roots or lost from the soil. This project will generate fundamental knowledge of how an Australian species and ....Feasting on protein? Strategies of organic nitrogen acquisition by plant roots. Crops require large amounts of nitrogen for growth. Application of nitrogen fertiliser enhances yield, but causes off-site nitrogen pollution, a main threat to ecosystem integrity. Most nitrogen in soil occurs as organic complexes that are broken down by soil organism into small compounds, which are taken up roots or lost from the soil. This project will generate fundamental knowledge of how an Australian species and a crop species with unusual root specialisations access soil organic nitrogen, thus increasing the efficiency of nitrogen use and reducing nitrogen loss. The research employs cutting-edge techniques for sustainable resource use, improved efficiency of crops and farming systems, and preservation of Australia's biodiversity.Read moreRead less
New Insights into the Structure and Function of Pyruvate Carboxylase. Pyruvate carboxylase plays an essential roles in insulin secretion by pancreatic islets and in normal brain function, but excess expression of this enzyme in liver and adipose tissue is associated with diabetes and obesity.
Understanding the function of each structural feature in the reaction mechanism of an enzyme is essential to designing safe and effective pharmaceuticals that are required to modulate its activity.
Th ....New Insights into the Structure and Function of Pyruvate Carboxylase. Pyruvate carboxylase plays an essential roles in insulin secretion by pancreatic islets and in normal brain function, but excess expression of this enzyme in liver and adipose tissue is associated with diabetes and obesity.
Understanding the function of each structural feature in the reaction mechanism of an enzyme is essential to designing safe and effective pharmaceuticals that are required to modulate its activity.
This project, which will use cutting edge techniques in an experimental model, seeks to characterise this important enzyme's function so that better treatments can be developed in future for diabetes and obesity.
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