cDNA cloning and 1.75 Å crystal structure determination of PPL2, an endochitinase and N‐acetylglucosamine‐binding hemagglutinin from Parkia platycephala seeds

• Published in: The FEBS journal Vol. 273; no. 17; pp. 3962 - 3974
• Main Authors: Cavada, Benildo S., Moreno, Frederico B. B., da Rocha, Bruno A. M., de Azevedo, Walter F., Castellón, Rolando E. R., Goersch, Georg V., Nagano, Celso S., de Souza, Emmanuel P., Nascimento, Kyria S., Radis‐Baptista, Gandhi, Delatorre, Plínio, Leroy, Yves, Toyama, Marcos H., Pinto, Vicente P. T., Sampaio, Alexandre H., Barettino, Domingo, Debray, Henri, Calvete, Juan J., Sanz, Libia
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2006
• Subjects: Acetylglucosamine - metabolism; Amino Acid Sequence; Base Sequence; Binding sites; Chitinases - chemistry; Chitinases - genetics; Chitinases - metabolism; Cloning; Cloning, Molecular; Crystal structure; Crystallization; Crystallography, X-Ray; Deoxyribonucleic acid; DNA; DNA, Complementary - isolation & purification; endochitinase; Enzymes; Fabaceae - enzymology; Fabaceae - genetics; glycosyl hydrolase family 18; Hemagglutinins - chemistry; Hemagglutinins - genetics; Hemagglutinins - metabolism; Mimosoideae; Molecular Sequence Data; Parkia platycephala; Plant Lectins - chemistry; Plant Lectins - genetics; Plant Lectins - metabolism; Protein Binding; Proteins; Seeds; Seeds - enzymology; Seeds - genetics; X‐ray crystal structure
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/j.1742-4658.2006.05400.x

Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP‐HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407 ± 15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N‐acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed β(1–4) glycosidic bonds linking 2‐acetoamido‐2‐deoxy‐β‐d‐glucopyranose units in chitin. The full‐length amino acid sequence of Parkia platycephala lectin 2, determined by N‐terminal sequencing and cDNA cloning, and its three‐dimensional structure, established by X‐ray crystallography at 1.75 Å resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (βα)8 barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182.