{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:27:59Z","timestamp":1785432479243,"version":"3.56.0"},"reference-count":37,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T00:00:00Z","timestamp":1781654400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Council for Science, Technology and Technological Innovation","award":["PE501092284-2024"],"award-info":[{"award-number":["PE501092284-2024"]}]},{"award":["PE501092284-2024"],"award-info":[{"award-number":["PE501092284-2024"]}],"id":[{"id":"https:\/\/ror.org\/05c7j7r25","id-type":"ROR","asserted-by":"publisher"}]},{"name":"National Program for Scientific Research and Advanced Studies","award":["PE501084300-2023-PROCIENCIA-BM"],"award-info":[{"award-number":["PE501084300-2023-PROCIENCIA-BM"]}]},{"award":["PE501084300-2023-PROCIENCIA-BM"],"award-info":[{"award-number":["PE501084300-2023-PROCIENCIA-BM"]}],"id":[{"id":"https:\/\/ror.org\/05pap9b79","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background\/Objectives: Tuberculosis remains a major public health challenge due to the persistence of Mycobacterium tuberculosis (Mtb) and the emergence of multidrug-resistant strains. In this study, Pep-H, an HNP-1-derived antimicrobial peptide with the sequence RRYGTCIYQGRLWAF-NH2, was used as a compact scaffold to examine how single-residue substitutions at the Cys position affected its biological and functional profile. Methods: A focused single-position substitution panel was generated by replacing Cys with Trp, Ala, Arg, or Met while preserving peptide length and sequence context, and the analogs were computationally prioritized according to their predicted antitubercular potential and contrasting side-chain properties. The peptides were synthesized, purified, characterized by HPLC and mass spectrometry, and evaluated for activity against Mtb H37Rv, cytotoxicity, hemolysis, ethidium bromide accumulation, and DPPH radical scavenging. Results: Pep-H retained the most favorable profile, showing the highest antimycobacterial potency, low hemolysis, favorable selectivity indices, enhanced ethidium bromide accumulation, and the strongest antioxidant response. All Cys substitutions reduced antimycobacterial activity, indicating that none of the tested residues reproduced the integrated biological profile of Pep-H. Conclusions: The contrasting outcomes of the Arg- and Met-containing analogs suggest that increased cationicity or sulfur retention alone was insufficient, while supporting a multifactorial contribution of Cys side-chain chemistry and the local GTCIY environment.<\/jats:p>","DOI":"10.3390\/antibiotics15060618","type":"journal-article","created":{"date-parts":[[2026,6,18]],"date-time":"2026-06-18T00:49:42Z","timestamp":1781743782000},"page":"618","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Comparative Biological and Functional Profiling of Single-Position Cysteine Substitutions in the HNP-1-Derived Peptide Pep-H Against Mycobacterium tuberculosis"],"prefix":"10.3390","volume":"15","author":[{"given":"Christian S.","family":"Carnero Canales","sequence":"first","affiliation":[{"name":"BIOMET, Laboratorio de Qu\u00edmica Bioinorg\u00e1nica en Medicina, Medioambiente y Tecnolog\u00eda, Facultad de Ciencias, Universidad Nacional de Ingenier\u00eda, Av. T\u00fapac Amaru 210, R\u00edmac, Lima 15333, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5554-3702","authenticated-orcid":false,"given":"Let\u00edcia Oliveira Catarin","family":"Nunes","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences, S\u00e3o Paulo State University (UNESP), Araraquara 14800-903, Brazil"},{"name":"Institute of Chemistry, S\u00e3o Paulo State University, Araraquara 14800-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3055-0447","authenticated-orcid":false,"given":"Ariani Rodrigues","family":"Arag\u00e3o","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, S\u00e3o Paulo State University, Araraquara 14800-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0344-6900","authenticated-orcid":false,"given":"Norival Alves","family":"Santos Filho","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences, S\u00e3o Paulo State University (UNESP), Araraquara 14800-903, Brazil"},{"name":"Institute of Chemistry, S\u00e3o Paulo State University, Araraquara 14800-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4316-6572","authenticated-orcid":false,"given":"Roxana Yesenia","family":"Pastrana Alta","sequence":"additional","affiliation":[{"name":"BIOMET, Laboratorio de Qu\u00edmica Bioinorg\u00e1nica en Medicina, Medioambiente y Tecnolog\u00eda, Facultad de Ciencias, Universidad Nacional de Ingenier\u00eda, Av. T\u00fapac Amaru 210, R\u00edmac, Lima 15333, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6969-3963","authenticated-orcid":false,"given":"Fernando Rog\u00e9rio","family":"Pavan","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences, S\u00e3o Paulo State University (UNESP), Araraquara 14800-903, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1038\/s41579-024-01025-1","article-title":"Drug-Resistant Tuberculosis: A Persistent Global Health Concern","volume":"22","author":"Farhat","year":"2024","journal-title":"Nat. Rev. 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