Resurfacing promotes antibacterial activity of a lipid A-binding nanobody

• 成果类型: Article
• 署名作者: O'Donnell, Angela C.; Wang, Xun; Kaderabkova, Nikol; Groover, Kyra E.; Perez, Bethany C.; Helms, Amanda; Brodbelt, Jennifer S.; Mavridou, Despoina A. I.; Davies, Bryan W.
• 署名单位: University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin; United States Department of Energy (DOE); Lawrence Livermore National Laboratory
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13766
• DOI: 10.1073/pnas.2509305122
• 发表日期: 2025-09-09
• 关键词: cationic antimicrobial peptides; permeability-increasing protein; outer-membrane; bacterial; surface; charge

摘要

Nanobodies have been pursued as candidates for antimicrobial design due to their small size and versatile binding capacities, but direct antibacterial activity of a nano-body has yet to be described. Here, we employed a bacterial surface display platform to screen a synthetic library of nanobody variants for antimicrobial potential. We identified a candidate that binds the essential lipid A component of gram-negative lipopolysaccharide. Nonetheless, this nanobody required a weakened outer membrane to access its target and elicit its toxic activity. Borrowing from observations of innate immune proteins, we found that resurfacing nanobodies with positively charged residues enabled them to bind and perturb the gram-negative outer membrane, but this alone was not sufficient for toxic activity. However, when we resurface our lipid A-targeting nanobody, it gained the ability to disrupt the outer membrane and enact its antibacterial function against wild-type bacteria. This development of a dual-function nanobody that can reach and bind previously inaccessible gram-negative targets introduces a route for antimicrobial biologic advancement.