Current research topics
Besides examining the proteins of human immunodeficiency viruses type 1 and 2 (HIV-1 and HIV-2), we are studying other retroviruses, including human T-cell leukemia viruses (HTLV-1, HTLV- 2 and HTLV-3) by biochemical characterization of its proteases. In addition, we investigate the properties of retrovirus-like proteins of eukaryotes, including humans, including DNA damage-induced protein (Ddi1 and Ddi2), PEG10 (paternally expressed gene 10) and skin-specific (ASPRV1) cellular dimer aspartyl proteases. The aim of our experiments is, among other things, to examine the structural and functional properties of the studied aspartyl proteases by both experimental and computational approaches, including the examination of activity, specificity and inhibition. In comparative studies, we analyze the general similarities and differences in the case of retroviruses and retrovirus-like proteins.
Our research group is also interested in the study of HIV-2 viral proteins, including determining the effectiveness of therapeutic inhibitors developed against HIV-1 against HIV-2 proteins, including viral protease and integrase, and investigation of the molecular background of HIV-1 an HIV-2 dual infection. The effectiveness of various inhibitors used in antiretroviral therapies are investigated in cell culture and in vitro experiments. Our goal is to identify the properties that influence the effectiveness of different inhibitors, as well as determine the specificity of retroviral, retroelement and cellular proteases.
Our research group is also interested in examining the proteins of other viruses that are significant from a health or biotechnological point of view, such as the proteases of the tobacco scratch virus (TEV) and the Venezuelan equine encephalitis virus (VEEV) and HIV-2 accessory proteins (e.g. Vpx).
We also aim to identify approaches that can increase the efficiency of protein expression and purification methods, including the investigation of fusion tag proteins, such as glutathione-S-transferase (GST), as well as the development and application of recombinant fusion protein substrates for the investigation of proteolytic enzymes.
After the outbreak of the SARS-CoV-2 coronavirus epidemic at the end of 2019, our research group started to examine coronavirus proteins, primarily the main protease and spike proteins. Our work so far has included the investigation of the ability of the SARS-CoV-2 protease to be inhibited by therapeutic HIV-1 protease inhibitors, the use of computer and experimental procedures to identify previously unknown protein substrates, the investigation of the molecular background behind the possible development of drug resistance, and the effect of the spike protein on the infected examination of effects on cells. Our coronavirus studies were carried out with the support of grant of the Hungarian Academy of Sciences (POST-COVID2021-06). Title of our application: In vitro study of the effects of SARS-CoV-2 infection and COVID-19 vaccination.
The main research area of the research laboratory includes the development of retrovirus-based gene therapy vectors, because retroviruses can be an important tool for gene therapy applications, due to the highly efficient integration that plays an essential role in their life cycle.
Our research group regularly participates in collaboration with other research groups, the aim of these work is to study the structure-function relationships of various proteins using in vitro or in silico methods, e.g. to investigate the effects of disease-associated protein mutations at protein level.
Previous research topics
One of the major research interests of the LRB is to study the biochemistry and enzymology of retroviral replication, with an emphasis on the function and features of the viral protease (PR). All replication competent retroviruses code for a PR. The function of the mature PR is critical for virion replication. The HIV-1 PR has proved to be an excellent target for antiretroviral therapy of AIDS, and various PR inhibitors are now in clinical use. However, there is a rapid selection of viral variants that are resistant to inhibitors of PR. Comparative studies of various PRs have revealed the common features of their specificity. These studies are expected to aid the rational design of broad-spectrum inhibitors effective against various retroviral proteinases, including the mutant HIV-1 enzymes appearing in drug resistance.
We have previously studied and characterized the PR of the following retrovirues: HIV-1, HIV-2, equine infectious anemia virus (EIAV), human T-cell leukemia virus (HTLV), bovine leukemia virus (BLV), avian myeloblastosis virus (AMV), and human foamy virus (HFV).
Members of the LRB are also involved in other collaborative works. These include studies of the homo- and heteroassociation patterns of MHC and ErbB receptors in collaboration with the research group of Dr. Janos Szollosi (Department of Biophysics, UD). Also, LRB is historically involved in studies on the proteolytic systems of the anterior segment of the eye, in collaboration with the team of Dr. Andras Berta (Department of Ophthalmology, UD). Another collaboration involves characterization of potyviral proteases, in collaboration with Dr. David Waugh (NCI-Frederick, USA).
The specificity of the proteases of eleven retroviruses was studied previously using a series of oligopeptides having single amino acid substitutions in various positions of a naturally occurring cleavage site of HIV-1. The protease set included at least one member from each of the seven genera of the family Retroviridae.