Glucose-Binding Dioclea bicolor Lectin (DBL): Purification, Characterization, Structural Analysis, and Antibacterial Properties

Willian F Reis; Marcos E S Silva; Ana C S Gondim; Renato C F Torres; Rômulo F Carneiro; Celso S Nagano; Alexandre H Sampaio; Claudener S Teixeira; Lenita C B F Gomes; Bruno L Sousa; Alexandre L Andrade; Edson H Teixeira; Mayron A Vasconcelos

doi:10.1007/s10930-024-10199-9

Glucose-Binding Dioclea bicolor Lectin (DBL): Purification, Characterization, Structural Analysis, and Antibacterial Properties

Protein J. 2024 Apr 14. doi: 10.1007/s10930-024-10199-9. Online ahead of print.

Authors

Affiliations

¹ Departamento de Ciências da Natureza E da Terra, Universidade Do Estado de Minas Gerais, Unidade de Divinópolis, Divinópolis, MG, Brazil.
² Faculdade de Educação de Itapipoca, Universidade Estadual Do Ceará, Itapipoca, CE, Brazil.
³ Faculdade de Ciências Exatas E Naturais, Universidade Do Estado Do Rio Grande Do Norte, Mossoró, RN, Brazil.
⁴ Departamento de Química Orgânica E Inorgânica, Universidade Federal Do Ceará, Fortaleza, CE, Brazil.
⁵ Centro de Ciências Agrárias E da Biodiversidade, Universidade Federal Do Cariri, Crato, CE, Brazil.
⁶ Laboratório de Biotecnologia Marinha - BioMar-Lab, Departamento de Engenharia de Pesca, Universidade Federal Do Ceará, Fortaleza, CE, Brazil.
⁷ Faculdade de Filosofia Dom Aureliano Matos, Universidade Estadual Do Ceará, Limoeiro Do Norte, CE, Brazil.
⁸ Laboratório Integrado de Biomoléculas - LIBS, Departamento de Patologia E Medicina Legal, Universidade Federal Do Ceará, Fortaleza, CE, Brazil.
⁹ Departamento de Ciências da Natureza E da Terra, Universidade Do Estado de Minas Gerais, Unidade de Divinópolis, Divinópolis, MG, Brazil. mayronvasconcelos@gmail.com.
¹⁰ Faculdade de Educação de Itapipoca, Universidade Estadual Do Ceará, Itapipoca, CE, Brazil. mayronvasconcelos@gmail.com.
¹¹ Faculdade de Ciências Exatas E Naturais, Universidade Do Estado Do Rio Grande Do Norte, Mossoró, RN, Brazil. mayronvasconcelos@gmail.com.

PMID: 38615284
DOI: 10.1007/s10930-024-10199-9

Abstract

In this study, we purified a lectin isolated from the seeds of Dioclea bicolor (DBL) via affinity purification. Electrophoresis analysis revealed that DBL had three bands, α, β, and γ chains, with molecular masses of approximately 29, 14, and 12 kDa, respectively. Gel filtration chromatography revealed that the native form of DBL had a molecular mass of approximately 100 kDa, indicating that it is a tetramer. Interestingly, DBL-induced hemagglutination was inhibited by several glucosides, mannosides, ampicillin, and tetracycline with minimum inhibitory concentration (MIC) values of 1.56-50 mM. Analysis of the complete amino acid sequence of DBL revealed the presence of 237 amino acids with high similarity to other Diocleinae lectins. Circular dichroism showed the prominent β-sheet secondary structure of DBL. Furthermore, DBL structure prediction revealed a Discrete Optimized Protein Energy (DOPE) score of -26,642.69141/Normalized DOPE score of -1.84041. The DBL monomer was found to consist a β-sandwich based on its 3D structure. Molecular docking showed the interactions between DBL and α-D-glucose, N-acetyl-D-glucosamine, α-D-mannose, α-methyl-D-mannoside, ampicillin, and tetracycline. In addition, DBL showed antimicrobial activity with an MIC of 125 μg/mL and exerted synergistic effects in combination with ampicillin and tetracycline (fractional inhibitory concentration index ≤ 0.5). Additionally, DBL significantly inhibited biofilm formation and showed no toxicity in murine fibroblasts (p < 0.05). These results suggest that DBL exhibits antimicrobial activity and works synergistically with antibiotics.

Keywords: Dioclea bicolor; Antimicrobial activity; ConA-like; Structural characterization; Synergistic effect.

Grants and funding

APQ-00224-21/Fundação de Amparo à Pesquisa do Estado de Minas Gerais