Research An Bracke

Abstract

The coronavirus SARS-CoV-2, causative of COVID-19, currently causes an unprecedented pandemic. Human SARS-CoV-2 infections are enabled by two events that occur at the host-virus interface. First, viral attachment to host cells is mediated by an interaction between the SARS-CoV-2 'spike' protein and its host receptor angiotensin converting enzyme 2 (ACE2).Next, the virus is "primed" for host cell entry through proteolytic cleavage of SARS-CoV-2-spike protein by other surface-exposed host proteases such as TMPRSS2. Inhibition of TMPRSS2-enabled "priming" negatively impacts SARS-CoV-2 infectivity. Unfortunately, the currently available TMPRSS2 inhibitors (such as camostat) are nonspecific. For the development of inhibitors with an increased specificity and high potency, a better knowledge of the characteristics of the protease are urgently needed. This project aims to lay the indispensable foundation for the rational design of specific TMPRSS2 inhibitors in the battle against SARS-CoV-2 and COVID-19. This will be realized in two work packages (WPs) and 6 interrelated and measurable deliverables (D). The project will focus on following research questions: (1) What is the extended substrate specificity of TMPRSS2? and (2) What is the correlation between TMPRSS2 inhibition and neutralization of SARSCoV- 2 infectivity in vitro? The deliverables of the project include the availability of active recombinant human TMPRSS2, methods to quantify its activity, data on the extended substrate specificity and on the inhibitory potency of a set of 100 compounds from the library of protease inhibitors of the UAntwerp research group on Medicinal Chemistry (UAMC). The correlation of the inhibitory potency of these compounds with their effect on in vitro infectivity of SARS-CoV-2, together with data on extended TMPRSS2 substrate specificity, are an indispensable prerequisite for optimal planning of larger collaborative projects on host protease targeting as a therapeutic approach in the fight against COVID-19. Moreover, given the recently acquired expertise in structural biology in our lab, this project will lay a solid foundation for future structural studies of hit compounds in complex with TMPRSS2, which can in turn fuel rational drug design to generate more potent and specific compounds.

Researcher(s)

• Promoter: De Meester Ingrid
• Co-promoter: Bracke An
• Co-promoter: Sterckx Yann

Research team(s)

• Medical Biochemistry

Project type(s)

• Research Project

Abstract

The control of Leishmania infections is becoming increasingly difficult due to parasite resistance to and treatment failure with existing drugs. In the quest for the development of novel antileishmanial therapies, compound X has been identified as a promising lead targeting both laboratory strains and clinical isolates of the parasite. Preliminary data obtained from studies with cultured Leishmania donovani parasites point towards the Leishmania donovani dynamin-1 like protein (LdoDNM1) as the target of compound X. However, a direct interaction between compound X and LdoDNM1 is yet to be validated. To investigate the interaction between compound X and LdoDNM1 through a combination of quantitative biophysical methods.

Researcher(s)

• Promoter: Bracke An

Research team(s)

Project type(s)

• Research Project

Abstract

The purpose of this project is the molecular, biochemical and biophysical characterization of the recently discovered chimeric protein, Androglobin (Hoogewijs, D. et al. (2011) Mol. Biol. Evol.). This chimeric protein consists of an N-terminal calpain-like domain, an internal, circular permutated globin domain, an IQ calmodulin-binding motif and an unknown carboxyterminal domain. Interestingly, the globin domain, which normally consists of eight consecutive α-helices (named A-H), is circularly permuted and split into two parts within androglobin. Androglobin is predominantly expressed in testis tissue of human and mice, more specifically in the post-meiotic phases of spermatogenesis. Therefor a role in spermatogenesis is suggested. In this project a structural and functional analysis of the protein will be performed. The ligand binding and protease activity of the full protein and of the separate domains will be performed. The structural characteristics of the protein will be studied using spectroscopy and X-ray diffraction analysis. Furthermore, the role of androglobine in spermatogenesis will be studied by determining the gene expression of sperm samples and testis biopsies. Because of this interdisciplinary approach, we hope to contribute to the unraveling of the function of this interesting protein.

Researcher(s)

• Promoter: Dewilde Sylvia
• Fellow: Bracke An

Research team(s)

Project type(s)

• Research Project

Abstract

The purpose of this project is the molecular, biochemical and biophysical characterization of the recently discovered chimeric protein, Androglobin (Hoogewijs, D. et al. (2011) Mol. Biol. Evol.). This chimeric protein consists of an N-terminal calpain-like domain, an internal, circular permutated globin domain, an IQ calmodulin-binding motif and an unknown carboxyterminal domain. Interestingly, the globin domain, which normally consists of eight consecutive α-helices (named A-H), is circularly permuted and split into two parts within androglobin. Androglobin is predominantly expressed in testis tissue of human and mice, more specifically in the post-meiotic phases of spermatogenesis. Therefor a role in spermatogenesis is suggested. In this project a structural and functional analysis of the protein will be performed. The ligand binding and protease activity of the full protein and of the separate domains will be performed. The structural characteristics of the protein will be studied using spectroscopy and X-ray diffraction analysis. Because of this interdisciplinary approach, we hope to contribute to the unraveling of the function of this interesting protein.

Researcher(s)

• Promoter: Dewilde Sylvia
• Fellow: Bracke An

Research team(s)

Project type(s)

• Research Project

Abstract

Comparative genomic studies have led to the recent identification of several novel globin types in Metazoa. These discoveries have revealed that the highly conserved 'globin fold' tertiary structure underpins a surprising diversity of functions beyond the familiar O2 supply functions of hemoglobin and myoglobin. At the end of 2011, our lab –together with an international consortium- has published in Mol. Biol. Evol. the discovery of a hitherto unrecognized family of chimeric proteins that possess an N-terminal calpain-like domain, an internal, circular permuted globin domain and an IQ calmodulin-binding motif (Hoogewijs, D. et al. (2011) Mol. Biol. Evol. [Epub ahead of print]). This new protein, androglobin, is expressed specifically in the testis, might be involved in spermatogenesis and can therefore have medical applications. The goal of the proposed project is the molecular, biochemical and biophysical characterization of the human and zebrafish androglobin. This will be done by : i) the expression of the recombinant protein and its domains; ii) the determination of the gas ligand binding and protease activity of the full protein and its domains; iii) the structural characterization of the protein using spectroscopic and X-ray crystallographic techniques. By combining the results obtained by these multidisciplinary approaches, we hope to contribute to the unraveling of the function of this extraordinary protein family.

Researcher(s)

• Promoter: Dewilde Sylvia
• Fellow: Bracke An

Research team(s)

Project type(s)

• Research Project