Snapshots of an enzyme in action: structural and mechanistic studies on the catalytic cycle of Escherichia coli ketol-acid reductoisomerase. Enzymes are required for almost every process that occurs in a living organism. For this reason, understanding how enzymes work is essential if we are to understand life itself. In this project we will investigate the enzyme KARI by capturing a series of snapshots of its atomic structure as it progresses through its working cycle. In addition, we will make ....Snapshots of an enzyme in action: structural and mechanistic studies on the catalytic cycle of Escherichia coli ketol-acid reductoisomerase. Enzymes are required for almost every process that occurs in a living organism. For this reason, understanding how enzymes work is essential if we are to understand life itself. In this project we will investigate the enzyme KARI by capturing a series of snapshots of its atomic structure as it progresses through its working cycle. In addition, we will make a series of small alterations to the atomic structure that will allow us to understand how the individual parts work together.Read moreRead less
Structure and inhibition of acetohydroxyacid synthase. Acetohydroxyacid synthase (AHAS) has been identified as the target for several widely used herbicides known as the sulfonylureas and imidazolinones. World-wide, these two herbicides account for $US2 billion in annual sales. The aim is to determine the three-dimensional structure of AHAS from several sources and in complex with these herbicides. Furthermore, AHAS appears to be an excellent target for the development of antibacterial compounds ....Structure and inhibition of acetohydroxyacid synthase. Acetohydroxyacid synthase (AHAS) has been identified as the target for several widely used herbicides known as the sulfonylureas and imidazolinones. World-wide, these two herbicides account for $US2 billion in annual sales. The aim is to determine the three-dimensional structure of AHAS from several sources and in complex with these herbicides. Furthermore, AHAS appears to be an excellent target for the development of antibacterial compounds and fungicides. Knowledge of the three dimensional structures of these enzymes will be important in the rational design of more effective inhibitors with improved selectivity.Read moreRead less
Molecular mechanisms of pilin glycosylation in Neisseria: a model system for protein glycosylation in bacteria. The disease causing bacteria Neisseria meningitidis and Neisseria gonorrhoeae are important human pathogens. Cell surface structures, called pili, are known to be important in allowing the bacteria to stick to host cells. Genetic and structural studies have identified that the protein subunits, which make up pili, are glycosylated - modified by the addition of sugars. Until recently ....Molecular mechanisms of pilin glycosylation in Neisseria: a model system for protein glycosylation in bacteria. The disease causing bacteria Neisseria meningitidis and Neisseria gonorrhoeae are important human pathogens. Cell surface structures, called pili, are known to be important in allowing the bacteria to stick to host cells. Genetic and structural studies have identified that the protein subunits, which make up pili, are glycosylated - modified by the addition of sugars. Until recently glycosylation of Gram-negative bacterial proteins was not thought to occur, however our recent work with these bacteria, and other groups studying Pseudomonas and Campylobacter, have shown that this process may be widespread. In our previous studies, we have identified and analysed a number of genes involved in pili glycosylation, in bacteria, which make known sugar structures. We have used this information to developed models for how the biochemistry and physiology of the glycosylation system may work. With a well-established structure and many genes already identified, glycosylation in Neisseria represents the best available model system to study this novel and important process. In the proposed study we describe experiments planned to test our models and reveal the molecular detail of this process. This study could lead to major advances in our understanding of this process and, when understood, may have future applications in biotechnology.Read moreRead less
Flaviviral Proteases As Viable Targets For Antiinfective Drugs
Funder
National Health and Medical Research Council
Funding Amount
$620,716.00
Summary
Viruses hijack the machinery and nutrients of cells they infect in order to reproduce. We will study viral enzymes (proteases) essential for virus replication, use fluorescent probes to learn where the viral enzymes hide and act in infected cells, track the passage of drugs aimed at these enzymes, design drugs to block their actions and stop virus replication, and test antiviral activity against Dengue, West Nile, Japanese Encephalitis and Yellow Fever viruses which infect millions of people.
Feeding and digestion in tropical rock lobster phyllosoma larvae and its applications for culture. Provision of larval culture diets that provide optimal nutrition in a suitable presentation format is the major challenge for developing a rock lobster aquaculture industry. Tropical rock lobsters are likely contenders due to their faster growth rates and shorter larval phase than temperate species. This project will assess the ingestive and digestive capabilities of larvae during development, thro ....Feeding and digestion in tropical rock lobster phyllosoma larvae and its applications for culture. Provision of larval culture diets that provide optimal nutrition in a suitable presentation format is the major challenge for developing a rock lobster aquaculture industry. Tropical rock lobsters are likely contenders due to their faster growth rates and shorter larval phase than temperate species. This project will assess the ingestive and digestive capabilities of larvae during development, through an examination of mouthpart and gut structure and their types and concentration of digestive enzymes. Information will be used to formulate and test improved diets of appropriate size, texture and nutritional composition and will be the first comprehensive analysis of preferred larval diets on the basis of their biological and physiological characteristics.Read moreRead less
Stuctural analysis of RNA polymerase elongation complexes. RNA polymerase (RNAP) is an essential enzyme in all living cells. Its role is to convert the genetic information stored in genes into a message that can be converted into protein. Many additional factors are required to ensure that this enzyme functions correctly in the cell. The aim of this project is to obtain structural information on a bacterial RNAP complexed with an essential transcription factor called NusA. Using this information ....Stuctural analysis of RNA polymerase elongation complexes. RNA polymerase (RNAP) is an essential enzyme in all living cells. Its role is to convert the genetic information stored in genes into a message that can be converted into protein. Many additional factors are required to ensure that this enzyme functions correctly in the cell. The aim of this project is to obtain structural information on a bacterial RNAP complexed with an essential transcription factor called NusA. Using this information, plus data already obtained on the structure of this enzyme complexed with another essential factor called sigma, we will design small molecules to inhibit the interaction of these essential factors with polymerase. These molecules will serve as leads for the development of new antibiotics.Read moreRead less
Host-pathogen interactions: the role of mimicry. The proposed research program, using a combination of structure and functional analysis will provide insight into the mechanism of nucleotide hydrolysis by the enzymes NTPDases. This study will not only improve our fundamental understanding of NTPDase action but could lead to the rational design of antimicrobials.
Insect development : the role of cytochrome P450s. Pest insects vector human diseases such as malaria and impose a massive burden in agriculture due to control costs and production losses. The intelligent control of insect pests requires an understanding of their development that is controlled by hormones. This project will provide an in depth understanding of insect hormone synthesis/degradation that is controlled by a class of enzymes, the cytochrome P450s. This will increase the potential ....Insect development : the role of cytochrome P450s. Pest insects vector human diseases such as malaria and impose a massive burden in agriculture due to control costs and production losses. The intelligent control of insect pests requires an understanding of their development that is controlled by hormones. This project will provide an in depth understanding of insect hormone synthesis/degradation that is controlled by a class of enzymes, the cytochrome P450s. This will increase the potential for new insect-specific control strategies with a decreased environmental impact.Read moreRead less
Mechanistic Studies of Dimethylsulfide Dehydrogenase: A Novel Bacterial Molybdoenzyme. The aim of this proposal is to use electrochemical, spectroscopic and molecular biological techniques to understand the mechanism of action of the enzyme dimethylsulfide dehydrogenase. This enzyme is representative of an major group of molybdenum-containing enzymes that have importance in microbial biotransformations. The project will provide fundamental information about a multi-redox centre protein that has ....Mechanistic Studies of Dimethylsulfide Dehydrogenase: A Novel Bacterial Molybdoenzyme. The aim of this proposal is to use electrochemical, spectroscopic and molecular biological techniques to understand the mechanism of action of the enzyme dimethylsulfide dehydrogenase. This enzyme is representative of an major group of molybdenum-containing enzymes that have importance in microbial biotransformations. The project will provide fundamental information about a multi-redox centre protein that has potential application in biosensors and biocatalysis.Read moreRead less
Structural studies of catalysis and electron transfer by copper proteins. We propose to determine the crystal structures of five copper-containing proteins. Three are amine oxidases, enzymes that protect a wide range of organisms against toxic cell products (amines). Novel chemical modifications and crystallographic techniques will be used to test hypotheses for the enzyme mechanism. The results will provide a basis for the future manipulation of the enzymes' activities. Our other targets, s ....Structural studies of catalysis and electron transfer by copper proteins. We propose to determine the crystal structures of five copper-containing proteins. Three are amine oxidases, enzymes that protect a wide range of organisms against toxic cell products (amines). Novel chemical modifications and crystallographic techniques will be used to test hypotheses for the enzyme mechanism. The results will provide a basis for the future manipulation of the enzymes' activities. Our other targets, sulfocyanin and auracyanin-A, perform essential electron-transfer functions in an archaeon and a photosynthetic bacterium, respectively. The determination of their molecular structures will answer exciting questions about electron transfer in primitive organisms, and about the evolution of copper proteins as biological electron-transfer agents.Read moreRead less