Antibacterial Activity Improvement in a Point Mutant K45E of the Pepper Defensin J1-1
Georgina Estrada 1, A,C,F
Gerardo Corzo 4, C,F
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Unidad de biología Integrativa, Centro de Investigación Científica de Yucatán A. C., Mexico
Unidad de Biología Integrativa, Centro de Investigación Científica de Yucatán A. C., Mexico
Facultad de Ciencias. Universidad Nacional Autónoma de México, Unidad Multidisciplinaria de Docencia e Investigación (UMIDI)-Sisal., Mexico
Instituto de Biotecnología, Universidad Nacional Autónoma de México, Mexico
These authors had equal contribution to this work
A - Research concept and design; B - Collection and/or assembly of data; C - Data analysis and interpretation; D - Writing the article; E - Critical revision of the article; F - Final approval of article
Submission date: 2024-01-27
Acceptance date: 2024-03-14
Online publication date: 2024-03-26
Corresponding author
Georgina Estrada   

Unidad de biología Integrativa, Centro de Investigación Científica de Yucatán A. C., calle 43 No. 130 x32 y34. Col Chuburná de Hidalgo , 97205, Merida, Mexico
  • • Recombinantly expressed point mutant J1-1K45E is active against Pseudomonas aeruginosa.
  • • This is the first report for an antibacterial plant defensin activity impovement by reducing defensin positive
  • charge.
  • • J1-1_K45E is active against Staphylococcus aureus.
  • • Defensin activity improvement might be related to changes in oligomerization or lipid selectivity in J1-1K45E.
Plant defensins have attracted much attention in the development of new antimicrobials. Yet the elucidation of their modes of action against bacterial pathogens is still incipient. The available recombinant systems to obtain plant defensin mutants with enhanced or optimized antibacterial activity may help to accelerate the knowledge of their action mechanisms and their applications against pathogens. In this work, the point mutant defensin K45E (J1-1_K45E) was obtained by the same recombinant system as J1-1 defensin. The characterized peptide conserved antibacterial activity against the gram-negative Pseudomonas aeruginosa and showed a dose improvement relative to J1-1. Furthermore, the mutant J1-1_K45E exhibited a gain in function against the gram-positive Staphylococcus aureus. Finally, to correlate structural changes and antibacterial activity, two properties involved in defensins’ modes of action were measured. First, the mutant J1-1_K45E which oligomerizes in a distinct pattern was compared with J1-1 and secondly, J1-1_K45E shows a distinct lipid binding profile because it binds preferentially to phosphatidylserine. Together, our findings support the idea that amino acid sequence variability in plant defensins superfamily can generate major functional changes, and highlight the relevant role of charged residues, beyond the -core loop, in the improvement of J1-1 antibacterial activity.
The authors have declared that no conflict of interests exist.
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