Biochemical and structural characterization of a mannose binding jacalin-related lectin with two-sugar binding sites from pineapple (Ananas comosus) stem

• Published in: Scientific reports 2018-07, Vol.8 (1), p.11508-14, Article 11508
• Main Authors: Azarkan, Mohamed, Feller, Georges, Vandenameele, Julie, Herman, Raphaël, El Mahyaoui, Rachida, Sauvage, Eric, Vanden Broeck, Arnaud, Matagne, André, Charlier, Paulette, Kerff, Frédéric
• Format: Article
• Language: English
• Subjects: 631/45/221; 631/45/72; 631/535/1266; 82/16; 82/29; 82/83; Affinity; Agglutination; Ananas comosus; Antiviral activity; Binding sites; Biochemistry, biophysics & molecular biology; Biochimie, biophysique & biologie moléculaire; Calorimetry; Conformation; Crystal structure; Erythrocytes; Gel electrophoresis; Hemagglutination; HIV; Human immunodeficiency virus; Humanities and Social Sciences; Lectins; Life sciences; Mannose; multidisciplinary; Science; Science (multidisciplinary); Sciences du vivant; Sodium lauryl sulfate; Sugar; Titration
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-29439-x

A mannose binding jacalin-related lectin from Ananas comosus stem (AcmJRL) was purified and biochemically characterized. This lectin is homogeneous according to native, SDS-PAGE and N-terminal sequencing and the theoretical molecular mass was confirmed by ESI-Q-TOF-MS. AcmJRL was found homodimeric in solution by size-exclusion chromatography. Rat erythrocytes are agglutinated by AcmJRL while no agglutination activity is detected against rabbit and sheep erythrocytes. Hemagglutination activity was found more strongly inhibited by mannooligomannosides than by D-mannose. The carbohydrate-binding specificity of AcmJRL was determined in some detail by isothermal titration calorimetry. All sugars tested were found to bind with low affinity to AcmJRL, with K a values in the mM range. In agreement with hemagglutination assays, the affinity increased from D-mannose to di-, tri- and penta-mannooligosaccharides. Moreover, the X-ray crystal structure of AcmJRL was obtained in an apo form as well as in complex with D-mannose and methyl-α-D-mannopyranoside, revealing two carbohydrate-binding sites per monomer similar to the banana lectin BanLec. The absence of a wall separating the two binding sites, the conformation of β7β8 loop and the hemagglutinating activity are reminiscent of the BanLec His84Thr mutant, which presents a strong anti-HIV activity in absence of mitogenic activity.