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Contents 1 Bromodomain of PfBDP1 2 Function 3 Disease 4 Relevance 5 References

Bromodomain of PfBDP1

spinqualitylabelsall models PDB ID 9HHD. Plasmodium Falciparum Bromodomain Containing protein 1 complexed with bromodomain inhibitor RMM2. MW 16.09 kDa res.325-456 2.69Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

In 2023, globally, there were an estimated 263 million new malaria cases and 597,000 deaths. Plasmodium falciparum, the causative parasite of malaria, invades red blood cells and consumes hemoglobin, preventing oxygen transport to the heart, resulting in heart failure. Additionally, parasitized RBCs stick to the wall of blood vessels in the heart and brain to evade the immune system, which leads to inflammation and blood vessel blockage to these vital organs thus, it is imperative to understand the essential factors involved in the P. falciparum RBC invasion process to develop therapeutic interventions. Previous research has shown that the P. falciparum Bromodomain Protein 1 (PfBDP1) plays an important role in red blood cell invasion by binding to acetylated chromatin at the promoters of invasion genes, promoting their expression. Additionally, knockdown of PfBPD1 impairs Plasmodium falciparum replication and strongly reduces expression of surface proteins involved in red blood cell invasion. This suggests that the chromatin binding activity of PfBDP1 plays an important role in P.falciparum biological fitness. A emerging therapeutic strategy is to block the binding of PfBDP1 to chromatin in order to inhibit the expression of genes implicated in red blood cell invasion.. The region within the PfBDP1 protein that is involved in chromatin binding, and thus downstream expression of genes that cause malaria, is the bromodomain. Bromodomains are a conserved structural motif within proteins whose primary function is to bind acetylated lysines on histones. Lysine acetylation is a well documented post translational modification on histones that is associated with active transcription. Bromodomains recognize these modifications and recruit transcriptional machinery to active promoters thus eliciting a key regulatory role in gene expression. Understanding the structure of bromodomains and identifying key residues involved in acetyl lysine binding is imperative to inform the development of molecules to block this interaction and thus impair the expression of genes implicated in disease. The bromodomain of PfBDP1 harbors , which is a conserved structural element amongst bromodomains. The core four helix bundle is arranged in two halves connected by The first half of the four helical bundle is comprised of the connected by the ZA loop, which has a well established role in ligand coordination. The end of the αZ helix encodes a that forms the bottom of the binding pocket and contains residues that contribute to ligand coordination via hydrophobic interactions. The second half of the conserved bromodomain fold is comprised of the that form the other side of the binding pocket. The αB helix and the αC helix are connected by the 3-residue long BC loop, which contains the conserved asparagine residue that is involved in the coordination of the acetyllysine moiety. Due to bromodomains crucial role in regulating transcription they have been the focus for small molecule inhibitor development. Currently, bromodomains are being targeted to combat cancer and autoimmune diseases however, targeting bromodomains to combat parasite related illnesses remain understudied. Aman et.al utilized virtual docking, isothermal titration calorimetry, and X-ray crystallography to determine the structure of the PfBDP1 bromodomain bound to a derivative of the bromodomain inhibitor MPM6. The involved in coordinating interactions with RMM2 are His354, Ile355, Gln365, Cys367, Asn413, Val419

Function

The bromodomain in PfBDP1, a protein in the malaria parasite Plasmodium falciparum, functions as a reader of histone acetylation, specifically binding to acetylated lysine residues on histone tails. This interaction allows PfBDP1 to regulate gene expression, particularly of genes involved in erythrocyte invasion. PfBDP1's bromodomain helps tether a transcriptional activator complex to acetylated histones, influencing the expression of genes required for parasite growth and invasion

Disease

Malaria pathogenesis involves several stages, primarily the asexual and sexual cycles of the Plasmodium parasite within the human host and the mosquito, respectively. The parasite invades liver cells (exoerythrocytic stage) and subsequently infects red blood cells (erythrocytic stage), causing symptoms like fever, chills, and anemia. The symptoms of malaria are associated with repeated rounds of parasite replication, egress, and invasion into the red blood cells. At the red blood cell stage of infection, P. falciparum consumes the RBCs hemoglobin, preventing it from carrying oxygen to the heart, which results in anemic heart failure4. In addition, parasitized RBCs stick to the wall of blood vessels in the heart and brain to evade the immune system, which often leads to inflammation and causes blood vessel blockage in these vital organs. These infection-related complications are directly associated with the invasion of RBCs by the parasite

Relevance

The most recent data from the World Health Organization (WHO) indicates that in 2023, there were an estimated 263 million malaria cases and 597,000 deaths globally. Treatment options are very limited and drug resistance is a major hurdle in combating malaria. The prevalence of Malaria coupled with the limited treatment options underpins the need for advancements in therapeutic strategies

References

References Gilan, O., Rioja, I., Knezevic, K., Bell, M. J., Yeung, M. M., Harker, N. R., Lam, E. Y. N., Chung, C. W., Bamborough, P., Petretich, M., Urh, M., Atkinson, S. J., Bassil, A. K., Roberts, E. J., Vassiliadis, D., Burr, M. L., Preston, A. G. S., Wellaway, C., Werner, T.,…Dawson, M. A. (2020). Selective targeting of BD1 and BD2 of the BET proteins in cancer and immunoinflammation. Science, 368(6489), 387-394. https://doi.org/10.1126/science.aaz8455 Gokani, S., & Bhatt, L. K. (2021). Bromodomains: A novel target for the anticancer therapy. Eur J Pharmacol, 911, 174523. https://doi.org/10.1016/j.ejphar.2021.174523 Josling, G. A., Petter, M., Oehring, S. C., Gupta, A. P., Dietz, O., Wilson, D. W., Schubert, T., Langst, G., Gilson, P. R., Crabb, B. S., Moes, S., Jenoe, P., Lim, S. W., Brown, G. V., Bozdech, Z., Voss, T. S., & Duffy, M. F. (2015). A Plasmodium Falciparum Bromodomain Protein Regulates Invasion Gene Expression. Cell Host Microbe, 17(6), 741-751. https://doi.org/10.1016/j.chom.2015.05.009 Miller, L. H., Good, M. F., & Milon, G. (1994). Malaria pathogenesis. Science, 264(5167), 1878-1883. https://doi.org/10.1126/science.8009217 Singh, A. K., Phillips, M., Alkrimi, S., Tonelli, M., Boyson, S. P., Malone, K. L., Nix, J. C., & Glass, K. C. (2022). Structural insights into acetylated histone ligand recognition by the BDP1 bromodomain of Plasmodium falciparum. Int J Biol Macromol, 223(Pt A), 316-326. https://doi.org/10.1016/j.ijbiomac.2022.10.247 (Gilan et al., 2020; Gokani & Bhatt, 2021; Josling et al., 2015; Singh et al., 2022)