The general aim of this work is to investigate the three-dimensional structures of important target proteins using X-ray crystallography. Protein crystallography is the study of the three-dimensional shapes of proteins at near atomic resolution. In this method proteins are made to form crystals. X-ray beams are then shone on the crystals causing the X-rays to scatter in a pattern which is characteristic of the protein's three-dimensional shape. Knowledge of the structure of proteins is necessary ....The general aim of this work is to investigate the three-dimensional structures of important target proteins using X-ray crystallography. Protein crystallography is the study of the three-dimensional shapes of proteins at near atomic resolution. In this method proteins are made to form crystals. X-ray beams are then shone on the crystals causing the X-rays to scatter in a pattern which is characteristic of the protein's three-dimensional shape. Knowledge of the structure of proteins is necessary for the complete understanding of their biological activity and is also very useful for the rational design of new drugs that may alter their activity. Approximately one third of the body's proteins are attached to membranes. However, relatively little is known about the three-dimensional structures of this important class of proteins. In this project the structures of proteins that form pores in membrane cell walls are being determined. Some of these proteins are bacterial toxins and knowledge of their structure may prove useful in the design of new antibiotics. Another project involves work on a protein called GABA. The structure of GABA could lead to new drugs that control epilepsy, act as general anaesthetics, relieve anxiety and induce sleep.Read moreRead less
Regulation Of Voltage-Gated Potassium Channels: X-ray Structures Of Cytosolic Components Of The BK Nd Kv Families
Funder
National Health and Medical Research Council
Funding Amount
$235,500.00
Summary
This research will investigate aspects of ion channel gating (opening). Ion channels are specialised pores perforating cell membranes that facilitate transport of ions, or charged atoms, across its breadth. The flow of ions from one side to another is measurable as an electrical current. The pore, or channel, through which ions pass narrows in regions, creating an impasse, or gate , prohibiting passage. The gate is controlled by external factors, such as the binding of certain molecules (ligands ....This research will investigate aspects of ion channel gating (opening). Ion channels are specialised pores perforating cell membranes that facilitate transport of ions, or charged atoms, across its breadth. The flow of ions from one side to another is measurable as an electrical current. The pore, or channel, through which ions pass narrows in regions, creating an impasse, or gate , prohibiting passage. The gate is controlled by external factors, such as the binding of certain molecules (ligands), or, in the case of voltage-dependent ion channels, the application of a voltage to the membrane. Such perturbations widen the pore sufficiently to permit conduction. Voltage-gated potassium channels specifically transport potassium ions. They fall into multiple categories, and generally form large complexes with intracellular, as well as membrane-bound, portions. For some types, cues from intracellular chemical processes are known to regulate electrical excitability, using the intracellular domains to transfer information to the membrane. In others it is not clear if and how this might happen. Our efforts will focus on exploring this theme in two contrasting systems, Kv and BK channels. Kv channels open in response to voltage, whereas activation of BK channels requires both voltage and moderate levels of intracellular calcium. X-ray crystallography will be used to generate accurate three-dimensional images of selected potassium channel components, allowing us to visualise discrete steps in the regulation processes. Potassium channels are essential for life. They effect transmission of our nerve impulses, and are thus fundamental to central nervous system activity. This research will help us to understand the factors that control them.Read moreRead less
This proposal concerns the biochemical investigation of a protein called GABA receptor which is a known target for various anti-anxiety drugs (anxiolytics), anti-convulsants, sedatives, depressants, anti-epilespy drugs, alcohol and anaesthetics. This work is expected to lead to the determination of the three-dimensional shape of the protein which will provide essential information about how the protein works and lay the foundation for the design and development of new drugs to control epilepsy, ....This proposal concerns the biochemical investigation of a protein called GABA receptor which is a known target for various anti-anxiety drugs (anxiolytics), anti-convulsants, sedatives, depressants, anti-epilespy drugs, alcohol and anaesthetics. This work is expected to lead to the determination of the three-dimensional shape of the protein which will provide essential information about how the protein works and lay the foundation for the design and development of new drugs to control epilepsy, act as general anaesthetics, relieve anxiety and induce sleep.Read 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
Amino acids as nutrients - the molecular basis of amino acid absorption in kidney and intestine. Nutrition is a critical factor for well being and health. This is highlighted by the increase in frequency of type II diabetes and the obesity problem that all societies with a western diet face. Most studies in nutrition focus on fat and carbohydrates because of their direct involvement in obesity and diabetes. Proteins and the resulting peptides and amino acids, however, form 10-15% of our nutritio ....Amino acids as nutrients - the molecular basis of amino acid absorption in kidney and intestine. Nutrition is a critical factor for well being and health. This is highlighted by the increase in frequency of type II diabetes and the obesity problem that all societies with a western diet face. Most studies in nutrition focus on fat and carbohydrates because of their direct involvement in obesity and diabetes. Proteins and the resulting peptides and amino acids, however, form 10-15% of our nutrition. At a time where protein-rich diets are recommended to fight obesity and diabetes, it is important to understand the basis of protein absorption and metabolism. This project investigates the mechanism and mediators of amino acid absorption in kidney and intestine. Read moreRead less
Calcium Signalling and Sequestration at Vertebrate Motor-Nerve Terminals. A fundamental process at Synapses is the release of transmitter from nerve terminals due to the initiation of calcium signalling in the temrinals by impulses. This calcium signalling must be terminated by sequestering processes. The aim of this project is to identify these processes in a vertebrate motor-nerve terminal and to determine the means by which calcium signals the changes in efficacy of transmitter release during ....Calcium Signalling and Sequestration at Vertebrate Motor-Nerve Terminals. A fundamental process at Synapses is the release of transmitter from nerve terminals due to the initiation of calcium signalling in the temrinals by impulses. This calcium signalling must be terminated by sequestering processes. The aim of this project is to identify these processes in a vertebrate motor-nerve terminal and to determine the means by which calcium signals the changes in efficacy of transmitter release during trains of impulses. This work will give a complete description of calcium signalling in a vertebrate nerve terminal and provide the basis for ameliorating failures in transmission from nerve to muscle.Read moreRead less
Conductance states of a brain glutamine transporter. Brain transporters are the target for many neuroactive drugs that are used to treat anxiety, depression and other psychotic disorders. Transport processes are also targeted to deliver neurotransmitter precursors to the brain to treat disorders such as Parkinson's disease. In this project we will study a transport process crucial for the function of neurons that release glutamate and GABA (gamma-aminobutyric acid) as neurotransmitters. The stud ....Conductance states of a brain glutamine transporter. Brain transporters are the target for many neuroactive drugs that are used to treat anxiety, depression and other psychotic disorders. Transport processes are also targeted to deliver neurotransmitter precursors to the brain to treat disorders such as Parkinson's disease. In this project we will study a transport process crucial for the function of neurons that release glutamate and GABA (gamma-aminobutyric acid) as neurotransmitters. The study of this transport process will be important for understanding disorders like epilepsy and other disorders affecting neuronal excitability.Read moreRead less
Probing membrane rafts using surface-selective multi-dimensional microscopy. The results of this project will provide fundamental insights into the role played by domains in cell membranes in the regulation of membrane protein function. These insights will create new avenues in the biotechnology industry for development of novel therapeutics aimed at disruption of membrane protein-protein interactions that cause aberant cell signalling in disease states such as cancer.
The role of omega-3 fatty acids in brain mechanisms that regulate water and salt balance. The ability of mammals to survive is heavily dependent upon their ability to maintain body fluid balance. This project aims to elucidate brain mechanisms for the behavioural regulation of water and salt balance, with specific investigation of the role of dietary fatty acids within these processes. It is hypothesised that omega-3 polyunsaturated fatty acids (PUFA) affect intake of water and salt by affecti ....The role of omega-3 fatty acids in brain mechanisms that regulate water and salt balance. The ability of mammals to survive is heavily dependent upon their ability to maintain body fluid balance. This project aims to elucidate brain mechanisms for the behavioural regulation of water and salt balance, with specific investigation of the role of dietary fatty acids within these processes. It is hypothesised that omega-3 polyunsaturated fatty acids (PUFA) affect intake of water and salt by affecting the sensitivity of various receptors, or the hormones used by this body system. Omega-3 PUFA are known to play a role in regulating genes, and therefore, may also affect the production of key proteins, such as receptors, hormones or enzymes involved in the regulation of salt and water intake.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