Role of a novel zinc-binding motif in the structure-function of deubiquitinating enzymes. The ubiquitin pathway destroys many proteins that control cell function and growth, by attaching ubiquitin to them and marking them for degradation. Deubiquitinating enzymes (DUBs) regulate protein destruction by controlling the amount of ubiquitin attached. DUBs and the ubiquitin pathway can also be manipulated in biotechnology applications. However, very little is known about the structure/function of DUB ....Role of a novel zinc-binding motif in the structure-function of deubiquitinating enzymes. The ubiquitin pathway destroys many proteins that control cell function and growth, by attaching ubiquitin to them and marking them for degradation. Deubiquitinating enzymes (DUBs) regulate protein destruction by controlling the amount of ubiquitin attached. DUBs and the ubiquitin pathway can also be manipulated in biotechnology applications. However, very little is known about the structure/function of DUBs. We have identified a new zinc-binding motif in DUBs, and we will explore how this contributes to their structure, and interactions with other proteins. This will significantly enhance our knowledge of how DUBs function in both biotechnology and in controlling cell function.Read moreRead less
Active bicarbonate transporters from cyanobacteria: physiological properties, genetic regulation, and introduction into plants for crop improvement. An intriguing set of membrane transport proteins that accumulate bicarbonate into marine cyanobacterial cells will be investigated. These proteins support the crucial process of photosynthetic carbon dioxide fixation in marine cyanobacteria (blue-green algae), which are major contributors to global carbon dioxide sequestration and form one of the f ....Active bicarbonate transporters from cyanobacteria: physiological properties, genetic regulation, and introduction into plants for crop improvement. An intriguing set of membrane transport proteins that accumulate bicarbonate into marine cyanobacterial cells will be investigated. These proteins support the crucial process of photosynthetic carbon dioxide fixation in marine cyanobacteria (blue-green algae), which are major contributors to global carbon dioxide sequestration and form one of the foundations of the marine food web. These bicarbonate "transporters" will also be transferred into a model plant system to test whether the efficiency of photosynthesis can be improved, with corresponding gains in the water-use efficiency of these plants. If successful this technology will have profound global implications for improving crop production in semi-arid areas.Read moreRead less
Directed evolution used to probe protein structure and function; new enzymes for bio-remediation and industry. The aim of the research is to generate new and useful enzymes for bio-remediation and other practical applications. For example, we are evolving enzymes to better degrade organophosphate pesticides that are environmental pollutants. Apart from producing useful enzymes, the proposed research aims at gaining a better understanding of how enzymes work and how they evolve. We intend to dete ....Directed evolution used to probe protein structure and function; new enzymes for bio-remediation and industry. The aim of the research is to generate new and useful enzymes for bio-remediation and other practical applications. For example, we are evolving enzymes to better degrade organophosphate pesticides that are environmental pollutants. Apart from producing useful enzymes, the proposed research aims at gaining a better understanding of how enzymes work and how they evolve. We intend to determine the structure of many related enzymes that have been evolved to have enhanced activities. This data will be used to analyze the intricate relationship between sequence, structure and enzyme activity.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
Nano-molecular structure and function of protein mini-compartments known as carboxysomes. Intriguing protein nano-structures, present in blue-green algae and known as carboxysomes, act as tiny compartments where CO2 can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-greens. This research aims to determine how the several proteins ....Nano-molecular structure and function of protein mini-compartments known as carboxysomes. Intriguing protein nano-structures, present in blue-green algae and known as carboxysomes, act as tiny compartments where CO2 can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-greens. This research aims to determine how the several proteins that make up carboxysomes come together to makeup carboxysome nano-structures and how these function to enhance rates of CO2 fixation. A more thorough understanding of the carboxysome is likely to have potential applications in industrial nano-technology and improvements in crop productivity.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
Directed evolution of enzymes for bioremediation: structure function studies of bimetalloenzymes. We will evolve enzymes that degrade organophosphate pesticides (OPs) that are used in Australian agriculture. Although these OPs were designed to kill insects they are closely related to chemical warfare agents and are known to be toxic to humans. Bacteria have acquired a number of enzymes that degrade some OPs. One such enzyme has been used in field trials demonstrating its potential to degrade OP ....Directed evolution of enzymes for bioremediation: structure function studies of bimetalloenzymes. We will evolve enzymes that degrade organophosphate pesticides (OPs) that are used in Australian agriculture. Although these OPs were designed to kill insects they are closely related to chemical warfare agents and are known to be toxic to humans. Bacteria have acquired a number of enzymes that degrade some OPs. One such enzyme has been used in field trials demonstrating its potential to degrade OP residues. However, many pesticides are not removed rapidly and OP-degrading enzymes require modification(s) if they are to be useful environmental reagents - this can be achieved with directed evolution. Read moreRead less