Novel Leptospira interrogans protein Lsa32 is expressed during infection and binds laminin and plasminogen

• Published in: Microbiology (Society for General Microbiology) Vol. 161; no. Pt 4; pp. 851 - 864
• Main Authors: Domingos, Renan F, Fernandes, Luis G, Romero, Eliete C, de Morais, Zenaide M, Vasconcellos, Silvio A, Nascimento, Ana L T O
• Format: Journal Article
• Language: English
• Published: England 01.04.2015
• Subjects: Bacterial Adhesion; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cloning, Molecular; Computational Biology; Extracellular Matrix; Gene Expression; Gene Expression Regulation, Bacterial; Genes, Bacterial; Laminin - metabolism; Leptospira interrogans - genetics; Leptospira interrogans - metabolism; Leptospirosis - microbiology; Plasminogen - metabolism; Protein Binding; Protein Transport; Transcription, Genetic
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.000041

Pathogenic Leptospira is the aetiological agent of leptospirosis, a life-threatening disease of human and veterinary concern. The quest for novel antigens that could mediate host-pathogen interactions is being pursued. Owing to their location, these antigens have the potential to elicit numerous activities, including immune response and adhesion. This study focuses on a hypothetical protein of Leptospira, encoded by the gene LIC11089, and its three derived fragments: the N-terminal, intermediate and C terminus regions. The gene coding for the full-length protein and fragments was cloned and expressed in Escherichia coli BL21(SI) strain by using the expression vector pAE. The recombinant protein and fragments tagged with hexahistidine at the N terminus were purified by metal affinity chromatography. The leptospiral full-length protein, named Lsa32 (leptospiral surface adhesin, 32 kDa), adheres to laminin, with the C terminus region being responsible for this interaction. Lsa32 binds to plasminogen in a dose-dependent fashion, generating plasmin when an activator is provided. Moreover, antibodies present in leptospirosis serum samples were able to recognize Lsa32. Lsa32 is most likely a new surface protein of Leptospira, as revealed by proteinase K susceptibility. Altogether, our data suggest that this multifaceted protein is expressed during infection and may play a role in host-L. interrogans interactions.