Computational design of a symmetrical β-trefoil lectin with cancer cell binding activity

• Published in: Scientific reports 2017-07, Vol.7 (1), p.5943-13, Article 5943
• Main Authors: Terada, Daiki, Voet, Arnout R. D., Noguchi, Hiroki, Kamata, Kenichi, Ohki, Mio, Addy, Christine, Fujii, Yuki, Yamamoto, Daiki, Ozeki, Yasuhiro, Tame, Jeremy R. H., Zhang, Kam Y. J.
• Format: Article
• Language: English
• Subjects: 631/114/469; 631/535/1266; 82/80; 82/83; Amino Acid Sequence; Animals; Binding Sites; Cancer; Cell Death; Cell Line, Tumor; Computational Biology; Computer applications; Crystallography, X-Ray; Cytotoxicity; D-Galactose; Galactose; Globotriose; Hemagglutination; Humanities and Social Sciences; Humans; Lectins; Lectins - chemistry; Lectins - metabolism; Lymphoma; Molecular Weight; Motivation; multidisciplinary; Neoplasms - metabolism; Neoplasms - pathology; Nucleotide sequence; Protein Domains; Protein Multimerization; Proteins; Rabbits; Science; Science (multidisciplinary); Shellfish; Sugars - metabolism; Trefoil Factors - chemistry
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-06332-7

Computational protein design has advanced very rapidly over the last decade, but there remain few examples of artificial proteins with direct medical applications. This study describes a new artificial β -trefoil lectin that recognises Burkitt’s lymphoma cells, and which was designed with the intention of finding a basis for novel cancer treatments or diagnostics. The new protein, called “Mitsuba”, is based on the structure of the natural shellfish lectin MytiLec-1, a member of a small lectin family that uses unique sequence motifs to bind α -D-galactose. The three subdomains of MytiLec-1 each carry one galactose binding site, and the 149-residue protein forms a tight dimer in solution. Mitsuba (meaning “three-leaf” in Japanese) was created by symmetry constraining the structure of a MytiLec-1 subunit, resulting in a 150-residue sequence that contains three identical tandem repeats. Mitsuba-1 was expressed and crystallised to confirm the X-ray structure matches the predicted model. Mitsuba-1 recognises cancer cells that express globotriose (Gal α (1,4)Gal β (1,4)Glc) on the surface, but the cytotoxicity is abolished.