Use Of Peptides From Phage Display Libraries To Probe The Function Of AMA-1 And Other Malaria Surface Proteins
Funder
National Health and Medical Research Council
Funding Amount
$316,650.00
Summary
Malaria remains a major cause of mortality and morbidity worldwide. Much current research is aimed at exploring the molecular interactions between malarial proteins and host components in order to gain a deeper understanding of parasite virulence mechanisms, design alternative anti-malarial approaches and improve vaccine design. The apical membrane antigen-1( AMA-1) is a surface exposed protein which is thought to play a crucial role in invasion of red blood cells by malaria parasites, and is cu ....Malaria remains a major cause of mortality and morbidity worldwide. Much current research is aimed at exploring the molecular interactions between malarial proteins and host components in order to gain a deeper understanding of parasite virulence mechanisms, design alternative anti-malarial approaches and improve vaccine design. The apical membrane antigen-1( AMA-1) is a surface exposed protein which is thought to play a crucial role in invasion of red blood cells by malaria parasites, and is currently one of the leading asexual stage vaccine candidates. While antibodies to AMA-1 prevents malaria invasion, little is known about the role of the antigen in the invasion process. The aim of this proposal is to investigate the molecular interactions that makes AMA-1 an important player in the invasion process. We propose to map the regions of AMA-1 responsible for binding a set of peptides which we have isolated from random peptide libraries. Since these peptides inhibit the invasion of parasites into red blood cells, regions of AMA1- that bind these peptides will be of functional significance. A further outcome will be the identification of peptide residues essential for the inhibition of invasion followed by in vitro evolution of these peptides to improve their binding and inhibitory properties. A molecular description of how AMA1 binding peptides prevent parasite invasion of host erythrocytes will improve our understanding of the invasion process, and aid in improving vaccines based on AMA-1. Furthermore, this peptide-AMA-1 interaction will be assessed as a possible target for the development of novel anti-malarial therapies. Using random peptide libraries we have selected peptides that specifically bind to other merozoite surface proteins thought to be involved in merozoite invasion of erythrocytes. The ability of these peptides to inhibit merozoite invasion will be examined and characterised as described above.Read moreRead less
Structural Basis For Inhibition Of Malaria Invasion By Targeting The Apical Membrane Antigen Of Plasmodium Falciparum.
Funder
National Health and Medical Research Council
Funding Amount
$434,134.00
Summary
3 million children die every year from malaria infections. A leading vaccine candidate is a protein from the malaria parasite called AMA1. Humans that have been infected with malaria make antibodies to this protein which can kill parasites, however little is known about how this occurs. We aim to identify regions of the protein that generate antibodies that prevent malaria parasites from invading human cells and help in the search for a vaccine against malaria.
Structure And Interactions Of The Malarial Vaccine Candidate AMA1
Funder
National Health and Medical Research Council
Funding Amount
$351,000.00
Summary
Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial d ....Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. A clearer understanding of the structure of parasite antigens such as AMA1 that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of host-parasite interactions. The aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 antigen. We shall also determine the structures, both in aqueous solution and bound to AMA1, of small peptides identified by phage display as being capable of binding to AMA1 and blocking parasite entry into red blood cells. The overall goal of this work is to determine the structure of AMA1 and define the structural basis for its interaction with small peptides capable of blocking its activity as well as the structural features necessary for AMA1 to react with protective antibodies. The structure of AMA1 will provide a molecular basis for the design of engineered antigens capable of eliciting a protective immune response against AMA1. The inhibitory peptide structures will likewise provide a molecular basis for the design of non-peptidic blockers of AMA1. Either or both of these may be useful therapeutics leads in the fight against malaria.Read moreRead less
Structure And Interactions Of The Malarial Surface Antigen AMA1
Funder
National Health and Medical Research Council
Funding Amount
$242,545.00
Summary
Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens ....Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of the host-parasite interaction. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. The specific aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 ectodomain. The interaction of one or more of these domains with Fab fragments of protective antibodies raised against intact AMA1 will then be investigated. We also intend to determine the conformations, both in aqueous solution and bound to AMA1, of oligopeptides identified by phage display as binding to AMA1 and blocking its binding to red blood cells. The overall goals of this work are to determine the structure of AMA1 and to define the structural basis for its interaction with antibodies and small peptides that are capable of blocking its activity. This information will provide a molecular basis for the design of either synthetic antigens capable of eliciting a protective immune response against AMA1 or peptidomimetic inhibitors of AMA1. Either or both of these may be useful in the prevention or treatment of malaria.Read moreRead less
Structure-function Relationships Of Rye Grass Pollen Allergens And Preparation Of Hypoallergenic Mutants For Therapy
Funder
National Health and Medical Research Council
Funding Amount
$223,928.00
Summary
Grass pollen is an important cause of allergy (eg. hayfever, allergic asthma) world-wide affecting up to 30% of the population. In Australia, rye grass pollen is a clinically significant health problem costing $83-160 million per annum. At present, the main treatment of seasonal allergy is by pharmacotherapy with the use of crude extracts in specific immunotherapy which often causes large and annoying local skin reactions and may even cause anaphylaxis. Moreover, the use of crude extracts in dia ....Grass pollen is an important cause of allergy (eg. hayfever, allergic asthma) world-wide affecting up to 30% of the population. In Australia, rye grass pollen is a clinically significant health problem costing $83-160 million per annum. At present, the main treatment of seasonal allergy is by pharmacotherapy with the use of crude extracts in specific immunotherapy which often causes large and annoying local skin reactions and may even cause anaphylaxis. Moreover, the use of crude extracts in diagnosis of allergy among some atopic individuals may be inaccurate or ineffective. In the last eight years of my research, I have contributed significantly to the identification, characterisation and molecular cloning of grass pollen allergens. In this proposal, I aim to evaluate recombinant rye grass pollen allergens as standardised and more effective diagnostic reagents and, through the identification and better understanding of the allergenic segments of these proteins, to prepare recombinant mutants of the same proteins which are no londer allergenic. Avaliability of such non-allergenic protein reagents will provide safer immunotherapy in the future. Moreover, since the biolgical role, function and structure of such allergens in the grass pollen still remain largely unknown, I will aim to investigate this with the clinically significant allergens of rye grass pollen. Determination of biological function and structure of such allergens will allow their importance for the pollen-plant to be determined and, since function may be relevant to sensitisation of suceptible individuals to these allergens, these findings will stimulate the development of novel concepts in allergen prevention and therapy.Read moreRead less
Great advances have been made in pharmaceutical design and discovery over the last 50 years. While drugs have traditionally been discovered using random screening of natural product libraries and chemical databases, new technologies in protein chemistry, structural and molecular biology have been adopted in efforts to speed the drug design process and increase its hit rate. In addition, our rapidly increasing knowledge of the molecular causes of many diseases provides us with many opportunities ....Great advances have been made in pharmaceutical design and discovery over the last 50 years. While drugs have traditionally been discovered using random screening of natural product libraries and chemical databases, new technologies in protein chemistry, structural and molecular biology have been adopted in efforts to speed the drug design process and increase its hit rate. In addition, our rapidly increasing knowledge of the molecular causes of many diseases provides us with many opportunities to develop therapeutics directed towards known molecular targets. Nevertheless, despite these advances, problems such as drug resistance and toxic side effects that compromise drug efficacy make it clear that there is a need for new classes of drugs with different modes of action. Because of their favourable properties, small-molecule drugs comprise by far the largest class of currently available therapeutics. However, in many cases, a drug derived from a protein may be preferable. The development of protein-based drugs is a youthful and rapidly expanding area of biotechnology, but to date, most studies have focused on targeting pathological events that occur on the outside of cells. We propose to use a combination of methods from molecular and structural biology, together with recently developed high-throughput screening techniques, to develop a generic protein drug scaffold that can be used as a template to develop therapeutics against a wide range of inappropriate interactions that may occur between molecules within cells.Read moreRead less
Molecular Characterization Of Unique Recognition Sites On The Surface Of Human Spermatozoa
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
Developing an understanding of the molecular mechanisms that regulate human sperm function is central to the clinical management of male infertility, attempts to develop novel forms of male contraception and strategies for the introduction of transgenes into the male germ line. Defective sperm function is the largest single defined cause of human infertility. Despite the prevalence of this condition we have no idea how most cases of male infertility arise nor, in a vast majority of patients, do ....Developing an understanding of the molecular mechanisms that regulate human sperm function is central to the clinical management of male infertility, attempts to develop novel forms of male contraception and strategies for the introduction of transgenes into the male germ line. Defective sperm function is the largest single defined cause of human infertility. Despite the prevalence of this condition we have no idea how most cases of male infertility arise nor, in a vast majority of patients, do we understand which particular aspect of sperm biochemistry is defective. As a consequence we have not been able to develop sensitive biochemical diagnostic tests for the infertile male nor do we have any rational methods of treatment that address the cause of this condition. Similarly no new methods of male fertility regulation have been introduced since vasectomy despite the major advances that have been made in the field of female contraception over the same period of time. Clearly if we are to develop sensitive methods for the diagnosis of defective sperm function, introduce protocols for the treatment and prevention of male infertility and discover novel approaches to male contraception, we must first understand the cellular mechanisms that enable these highly specialized cells to perform their unique function. In this study we shall focus on one of the most important attributes of sperm function the capacity of these cells to recognize the egg. Once the biochemical basis of this fundamental recognition process is understood, it should pave the way for the development of clinical applications that target this signaling system with implications for a range of disciplines including reproductive toxicology, occupational medicine, family planning, infertility and biotechnology.Read moreRead less