Recombinant human N-acetylneuraminate lyase as a tool to study clinically relevant mutant variants

• Published in: Carbohydrate research Vol. 516; p. 108561
• Main Authors: Cheng, Cheng, Hu, Zi-Xuan, He, Meng, Liu, Li, Voglmeir, Josef
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.06.2022
• Subjects: N-acetylneuraminate lyase; N-acetylneuraminic acid; NPL; Sialic acid; Sialic acid aldolase; Sialuria; Sialuria; Sialic acid; NPL; N-acetylneuraminate lyase; Sialic acid aldolase; N-acetylneuraminic acid
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2022.108561

N-acetylneuraminic acid (sialic acid) is an abundantly found carbohydrate moiety covering the surface of all vertebrate cells and secreted glycoproteins. The human N-acetylneuraminate pyruvate lyase (NPL) interconverts sialic acid to N-acetylmannosamine and pyruvate, and mutations of the NPL gene were found to cause sialuria and impair the functionality of muscles. Here we report the soluble and functional expression of human NPL in Escherichia coli, which allowed us to study the biochemical properties of two clinically relevant NLP mutations (Asn45Asp and Arg63Cys). The Asn45Asp mutant variant was enzymatically active, but had lower expression levels and showed reduced stability when compared to the wild-type NPL variant. Expression trials of the Arg63Cys mutant did not yield any recombinant protein and consequently, no enzymatic activity was detected. The locations of these clinically relevant amino acid substitutions are also discussed by using a human NPL homology model. [Display omitted] •First report of soluble and functional expression of human NPL in Escherichia coli.•Determination of the biochemical properties of two clinically relevant NLP mutations (Asn45Asp and Arg63Cys).•Simple methodology which is also adaptable to yet unknown mutations of human NPL.