---
title: "DNA aptamers targeting HasA hemophore in Pseudomonas aeruginosa as a potential antimicrobial appro"
id: "biorxiv-17-dna-aptamers-to-interfere-with-hasa-the-hemophore-of-the-heme-assimilation"
canonical_url: "https://medichelpline.com/clinical-feed/biorxiv-17-dna-aptamers-to-interfere-with-hasa-the-hemophore-of-the-heme-assimilation"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "bioRxiv (Biomedical Preprints)"
source_url: "https://www.biorxiv.org/content/10.64898/2026.09.03.749098v1?rss=1"
published_at: "2026-09-05T12:00:00.000Z"
evidence_level: "Verified Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# DNA aptamers targeting HasA hemophore in Pseudomonas aeruginosa as a potential antimicrobial appro
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/biorxiv-17-dna-aptamers-to-interfere-with-hasa-the-hemophore-of-the-heme-assimilation
- **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/10.64898/2026.09.03.749098v1?rss=1)
- **Published At:** 2026-09-05T12:00:00.000Z
- **Evidence Rating:** Verified Feed
## Executive GIST (TL;DR)
- Pseudomonas aeruginosa depends on **heme acquisition** to grow and maintain virulence in iron-limited, acidic host environments such as cystic fibrosis airways. - The Has heme assimilation system begins with the secreted hemophore **HasA**, which binds extracellular heme and delivers it to the HasR receptor; during infection HasA is proteolytically truncated and this truncated form is biologically relevant. - The study characterized truncated HasA at disease-associated acidic pH (pH 6.5): the protein is folded, shows a mixed **α/β secondary structure**, and exists as a concentration-dependent mix of monomers and domain-swapped dimers. - Thermal analyses (circular dichroism and nano-DSF) detected two thermal transitions, consistent with coexistence of apo/holo and monomer/dimer species. - The apo truncated HasA binds heme with high affinity (KD = 113 nM) and a 1:1 stoichiometry, preserving functional heme binding. - A rationally designed SELEX protocol (12 rounds, including target switching and platform switching) was used to identify **DNA aptamers** that bind truncated HasA under acidic conditions. - The enriched aptamer pool was dominated by two sequences, HasA_1 and HasA_2. - ELONA assays showed both aptamers specifically bind truncated HasA; biolayer interferometry returned nanomolar dissociation constants (KD = 0.59 μM and 0.32 μM for HasA_1 and HasA_2, respectively). - The aptamers did not bind full-length HasA, bovine serum albumin (BSA), or control sequences, indicating selection under acidic conditions produced specificity for the physiologically relevant truncated form. - The aptamers remain functional in acidic environments where antibiotic potency is reduced, suggesting potential as molecular tools to disrupt heme acquisition and a foundation for aptamer-based antimicrobial strategies targeting the Has system. - The source did not report downstream in vivo efficacy, clinical testing, or detailed therapeutic delivery strategies; those details were not reported in the article.
## Clinical Analysis & Structured Key Points
Pseudomonas aeruginosa relies on heme acquisition to sustain growth and virulence in the iron-limited environment of the host, particularly in the acidic airways of patients with cystic fibrosis where antibiotic efficacy is markedly reduced. The Has heme assimilation system is initiated by the secreted hemophore HasA, which binds extracellular heme and delivers it to the outer-membrane receptor HasR. During infection, HasA is proteolytically processed, generating a truncated form that constitutes the biologically relevant species. Here, we characterise the structural and functional properties of truncated HasA under disease-associated acidic conditions (pH 6.5) and perform a rationally designed Systemic Evolution of Ligands by EXponential enrichment (SELEX) method to identify DNA aptamers capable of binding this hemophore. Biophysical analyses revealed that truncated HasA is folded, displays a mixed /{beta} secondary structure, and exists as a concentration-dependent mixture of monomers and domain-swapped dimers. Circular dichroism and nano-differential scanning fluorimetry identified two thermal transitions, consistent with the coexistence of apo/holo and monomer/dimer species. The apo protein bound heme with high affinity (KD = 113 nM) and a 1:1 stoichiometry, confirming preservation of its functional binding mechanism. Twelve rounds of SELEX, incorporating target switching and platform switching, yielded a highly enriched aptamer pool dominated by two sequences, HasA_1 and HasA_2. ELONA (Enzyme-Linked Oligonucleotide Assay) assays demonstrated that both aptamers bind specifically to truncated HasA, and biolayer interferometry revealed nanomolar dissociation constants (KD = 0.59 M and 0.32 M, respectively). These aptamers did not bind full-length HasA, BSA, or control sequences, confirming that selection under acidic conditions drove specificity toward the physiologically relevant form of the hemophore. Our findings identify HasA-binding DNA aptamers that retain function in acidic environments where antibiotic potency is compromised, highlighting their potential as molecular tools to disrupt heme acquisition in P. aeruginosa. This work establishes a foundation for developing aptamer-based antimicrobial strategies targeting the Has system, particularly under acidic conditions where conventional antibiotics are compromised.
## Related Clinical Research

- [WHO validates Bhutan for eliminating dog-transmitted human rabies](https://medichelpline.com/clinical-feed/who-0-0-who-validates-bhutan-for-eliminating-dog-transmitted-human-rabies.md)
- [Infection prevention and control implementation during COVID-19 in sub-Saharan Africa: multination](https://medichelpline.com/clinical-feed/bmj-open-0-infection-prevention-and-control-measures-during-the-covid-19-pandemic-in-sub.md)
- [High AUROC can hide threshold failure in sepsis transcriptomic classifiers: preprocessing stabilit](https://medichelpline.com/clinical-feed/plos-one-13-high-auroc-can-mask-decision-failure-in-sepsis-transcriptomic-classifiers.md)
- [HPV and HPV vaccine awareness in Indigenous communities of Northwest Territories, Canada](https://medichelpline.com/clinical-feed/plos-one-12-human-papillomavirus-hpv-and-hpv-vaccine-awareness-in-indigenous-communities-in.md)
- [Serotype-specific dengue transmission intensity in Mexico (2016–2023): national modelling analysis](https://medichelpline.com/clinical-feed/plos-medicine-1-overall-and-serotype-specific-dengue-virus-transmission-intensity-in-mexico.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.