---
title: "Peptidyl Protease Inhibitors Target ERM-BP to Block Entamoeba Encystation"
id: "biorxiv-8-peptidyl-protease-inhibitors-block-erm-bp-function-and-suppress-entamoeba"
canonical_url: "https://medichelpline.com/clinical-feed/biorxiv-8-peptidyl-protease-inhibitors-block-erm-bp-function-and-suppress-entamoeba"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "bioRxiv (Biomedical Preprints)"
source_url: "https://www.biorxiv.org/content/10.64898/2026.09.16.752027v1?rss=1"
published_at: "2026-09-20T12:00:00.000Z"
evidence_level: "Verified Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Peptidyl Protease Inhibitors Target ERM-BP to Block Entamoeba Encystation
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/biorxiv-8-peptidyl-protease-inhibitors-block-erm-bp-function-and-suppress-entamoeba
- **Specialty:** [Infectious Disease](https://medichelpline.com/clinical-feed/infectious-disease.md)
- **Primary Source:** bioRxiv (Biomedical Preprints)
- **Source URL:** [Original Journal Publication](https://www.biorxiv.org/content/10.64898/2026.09.16.752027v1?rss=1)
- **Published At:** 2026-09-20T12:00:00.000Z
- **Evidence Rating:** Verified Feed
## Executive GIST (TL;DR)
- Entamoeba encystation is essential for parasite persistence and transmission; molecular control of this developmental stage is a therapeutic target. - The Encystation Regulatory Motif-Binding Protein (**ERM-BP**) is a transcription factor and a key regulator of encystation, making it an attractive drug target. - The study used a target-based screen focused on the functionally important **Cys-198** residue of ERM-BP. - A library of 100 compounds (including nicotinamidase inhibitors and cysteine-reactive electrophiles) was screened by Protein Thermal Shift Assays (PTSA). - Thirty-six compounds bound wild-type ERM-BP; comparison with a C198A mutant reduced candidates to three **Cys-198-dependent** binders. - The three identified peptidyl protease inhibitors are PFMK (Z-Ala-Phe-FMK), LEK (Z-Leu-EK), and EBLL (Ethylbenzyl-Leu-Lys). - PFMK, LEK and EBLL bound ERM-BP wild type and abolished ERM-BP DNA-binding activity in a concentration-dependent manner in vitro. - Cellular assays showed distinct effects: PFMK and EBLL reduced encystation efficiency, produced irregular and structurally defective cysts that failed to excyst; LEK did not significantly affect encystation efficiency or cyst morphology. - The work identifies **PFMK** and **EBLL** as promising compounds to target ERM-BP and block Entamoeba encystation, offering a framework for developing therapeutics against parasite differentiation and transmission. - Specific experimental details (concentrations, quantitative metrics, assay parameters) beyond those reported in the source were not provided in the article preview.
## Clinical Analysis & Structured Key Points
Peptidyl Protease Inhibitors Block ERM-BP Function and Suppress Entamoeba Encystation | bioRxiv Skip to main content Confirmatory Results Peptidyl Protease Inhibitors Block ERM-BP Function and Suppress Entamoeba Encystation View ORCID Profile Shreyasee Hazra , View ORCID Profile Suman Kalyan Dinda , View ORCID Profile Somashree Pandit , View ORCID Profile Dipak Manna doi: https://doi.org/10.64898/2026.09.16.752027 Shreyasee Hazra Ramakrishna Mission Vivekananda Educational and Research Institute Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Shreyasee Hazra Suman Kalyan Dinda Ramakrishna Mission Vivekananda Educational and Research Institute Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Suman Kalyan Dinda Somashree Pandit Ramakrishna Mission Vivekananda Educational and Research Institute Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Somashree Pandit Dipak Manna Ramakrishna Mission Vivekananda Educational and Research Institute Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Dipak Manna For correspondence: dipak.manna{at}gm.rkmvu.ac.in Abstract Info/History Metrics Preview PDF Abstract Entamoeba encystation process is a crucial developmental process that support to parasite persistence and disease transmission, yet the molecular mechanisms governing this stage conversion remain poorly understood and represent an attractive opportunity for therapeutic intervention. The Encystation Regulatory Motif-Binding Protein (ERM-BP), a transcription factor and key regulator of encystation, therefore represents a promising target for anti-amoebic drug development to prevent disease transmission. In the present study, we applied a target-based drug discovery approach to screen small molecules that can block the activity of ERM-BP, with a particular focus on the Cys-198 residue of this protein, which is functionally important. A library comprising 100 compounds including broad-spectrum nicotinamidase inhibitors and cysteine-reactive electrophiles were screened against ERM-BP by Protein thermal shift assays (PTSA). Thirty-six compounds bound to wild-type ERM-BP while analysis using the C198A mutant narrowed the candidates to three compounds exhibiting Cys-198-dependent interactions. These three peptidyl protease inhibitors, PFMK (Z-Ala-Phe-FMK), LEK (Z-Leu-EK), and EBLL (Ethylbenzyl-Leu-Lys) binds to ERM-BP-WT and abolishes the DNA-binding activity of ERM-BP in a concentration-dependent way. Cellular evaluation further revealed distinct activity of PFMK, LEK and EBLL on trophozoite growth and PFMK and EBLL reduced encystation efficiency significantly, produced irregular, and structurally defective cysts, which fails to excyst to trophozoites, whereas LEK had no significant effects on encystation efficiency or cyst morphology. Altogether, these findings identify peptidyl protease inhibitors PFMK and EBLL as promising compounds to target ERM-BP and block the Entamoeba encystation, providing a framework for developing therapeutics targeting parasite differentiation and encystation. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license . Back to top Previous Next Posted September 20, 2026. Download PDF Email Thank you for your interest in spreading the word about bioRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. You are going to email the following Peptidyl Protease Inhibitors Block ERM-BP Function and Suppress Entamoeba Encystation Message Subject (Your Name) has forwarded a page to you from bioRxiv Message Body (Your Name) thought you would like to see this page from the bioRxiv website. Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Share Peptidyl Protease Inhibitors Block ERM-BP Function and Suppress Entamoeba Encystation Shreyasee Hazra , Suman Kalyan Dinda , Somashree Pandit , Dipak Manna bioRxiv 2026.09.16.752027; doi: https://doi.org/10.64898/2026.09.16.752027 Share This Article: Copy Citation Tools Peptidyl Protease Inhibitors Block ERM-BP Function and Suppress Entamoeba Encystation Shreyasee Hazra , Suman Kalyan Dinda , Somashree Pandit , Dipak Manna bioRxiv 2026.09.16.752027; doi: https://doi.org/10.64898/2026.09.16.752027 Citation Manager Formats BibTeX Bookends EasyBib EndNote (tagged) EndNote 8 (xml) Medlars Mendeley Papers RefWorks Tagged Ref Manager RIS Zotero Tweet Widget Facebook Like Google Plus One Subject Areas All Articles Animal Behavior and Cognition (8013) Biochemistry (18739) Bioengineering (14888) Bioinformatics (44418) Biophysics (22599) Cancer Biology (19723) Cell Biology (26899) Clinical Trials (138) Developmental Biology (13965) Ecology (21005) Epidemiology (2067) Evolutionary Biology (25455) Genetics (16166) Genomics (23507) Immunology (18705) Microbiology (42503) Molecular Biology (18059) Neuroscience (93451) Paleontology (700) Pathology (2977) Pharmacology and Toxicology (5095) Physiology (8114) Plant Biology (15999) Scientific Communication and Education (2095) Synthetic Biology (4560) Systems Biology (10235) Zoology (2391)
## Related Clinical Research

- [Understanding Parasitic Identification in Delusional Parasitosis](https://medichelpline.com/clinical-feed/plos-one-21-bridging-perception-and-reality-parasitic-identification-in-delusional.md)
- [COVID-19 mortality among people with HIV in Florida before and after COVID-19 vaccine availability](https://medichelpline.com/clinical-feed/plos-one-13-covid-19-mortality-risk-among-people-with-hiv-in-florida-before-and-after-the.md)
- [Member States advance negotiations on pathogen access and benefit-sharing ahead of UN General Asse](https://medichelpline.com/clinical-feed/who-0-1-member-states-advance-negotiations-on-pathogen-access-and-benefit-sharing-ahead.md)
- [WHO launches new primary health care course to strengthen health systems globally](https://medichelpline.com/clinical-feed/who-0-0-who-launches-new-primary-health-care-course-to-strengthen-health-systems.md)
- [Simple sequence repeat INDELs in Mycobacterium tuberculosis influence antibiotic susceptibility](https://medichelpline.com/clinical-feed/biorxiv-4-variation-in-multiple-classes-of-simple-sequence-repeats-can-alter-drug.md)

## Navigation
- [← Back to Infectious Disease Feed](https://medichelpline.com/clinical-feed/infectious-disease.md)
- [← All Clinical Specialties](https://medichelpline.com/clinical-feed.md)
## Medical & Regulatory Disclaimer

> [!CAUTION]
> MedicHelpline content is structured for research, educational, and professional discovery purposes. It does not constitute individual medical advice, clinical diagnosis, or treatment recommendations.
> Always verify dosing, contraindications, and regulatory alerts against official product labeling and primary regulatory sources before clinical decision-making.