Structural Insights into the Interactions of Candidal Enolase with Human Vitronectin, Fibronectin and Plasminogen

• Published in: International journal of molecular sciences Vol. 21; no. 21; p. 7843
• Main Authors: Satala, Dorota, Satala, Grzegorz, Karkowska-Kuleta, Justyna, Bukowski, Michal, Kluza, Anna, Rapala-Kozik, Maria, Kozik, Andrzej
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22-10-2020; MDPI
• Subjects: Amino Acid Motifs; Antibodies - metabolism; Binding; Binding sites; Binding, Competitive; Biodegradation; Candida albicans - enzymology; Candida tropicalis - enzymology; Catalytic activity; Cell surface; Crosslinking; Cytosol - enzymology; enolase; Enzymes; Extracellular matrix; Fibrinolysis; Fibronectin; Fibronectins - chemistry; Fibronectins - metabolism; Fungi; Glycolysis; Host-Pathogen Interactions - physiology; Human tissues; Humans; Immobilized Proteins - metabolism; Infections; Ligands; Models, Molecular; moonlighting protein; non-albicans Candida species; Pathogens; Phosphopyruvate hydratase; Phosphopyruvate Hydratase - chemistry; Phosphopyruvate Hydratase - genetics; Phosphopyruvate Hydratase - immunology; Phosphopyruvate Hydratase - metabolism; plasminogen; Plasminogen - chemistry; Plasminogen - metabolism; Protein interaction; Proteins; Surface plasmon resonance; Virulence; Vitronectin; Vitronectin - chemistry; Vitronectin - metabolism; plasminogen; non-albicans Candida species; vitronectin; enolase; fibronectin; moonlighting protein
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21217843

Significant amounts of enolase-a cytosolic enzyme involved in the glycolysis pathway-are exposed on the cell surface of Candida yeast. It has been hypothesized that this exposed enolase form contributes to infection-related phenomena such as fungal adhesion to human tissues, and the activation of fibrinolysis and extracellular matrix degradation. The aim of the present study was to characterize, in structural terms, the protein-protein interactions underlying these moonlighting functions of enolase. The tight binding of human vitronectin, fibronectin and plasminogen by purified
and
enolases was quantitatively analyzed by surface plasmon resonance measurements, and the dissociation constants of the formed complexes were determined to be in the 10
-10
M range. In contrast, the binding of human proteins by the
enzyme was much weaker. The chemical cross-linking method was used to map the sites on enolase molecules that come into direct contact with human proteins. An internal motif
DKAGYKGKVGIAMDVASSEFYKDGK
in
enolase was suggested to contribute to the binding of all three human proteins tested. Models for these interactions were developed and revealed the sites on the enolase molecule that bind human proteins, extensively overlap for these ligands, and are well-separated from the catalytic activity center.