Characterization of a novel N-acetylneuraminic acid lyase favoring industrial N-acetylneuraminic acid synthesis

Sci Rep. 2015 Mar 23:5:9341. doi: 10.1038/srep09341.

Abstract

N-Acetylneuraminic acid lyase (NAL, E.C. number 4.1.3.3) is a Class I aldolase that catalyzes the reversible aldol cleavage of N-acetylneuraminic acid (Neu5Ac) from pyruvate and N-acetyl-D-mannosamine (ManNAc). Due to the high Neu5Ac cleavage activity in most isozyme forms, the enzyme catalyzes the rate-limiting step of two biocatalytic reactions producing Neu5Ac in industry. We report the biochemical characterization of a novel NAL from a "GRAS" (General recognized as safe) strain C. glutamicum ATCC 13032 (CgNal). Compared to all previously reported NALs, CgNal exhibited the lowest kcat/Km value for Neu5Ac and highest kcat/Km values for ManNAc and pyruvate, which makes CgNal favor industrial Neu5Ac synthesis process in a non-equilibrium condition. The recombinant CgNal reached the highest expression level (480 mg/L culture), and the highest reported yield of Neu5Ac was achieved (194 g/L, 0.63 M). All these unique properties make CgNal a promising biocatalyst for industrial Neu5Ac biosynthesis. Additionally, although showing the best Neu5Ac synthesis activity among the NAL family, CgNal is more related to dihydrodipicolinate synthase (DHDPS) by phylogenetic analysis. The activities of CgNal towards both NAL's and DHDPS' substrates are fairly high, which indicates CgNal a bi-functional enzyme. The sequence analysis suggests that CgNal might have adopted a unique set of residues for substrates recognition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biocatalysis
  • Cloning, Molecular
  • Corynebacterium glutamicum / chemistry*
  • Corynebacterium glutamicum / classification
  • Corynebacterium glutamicum / enzymology
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Gene Expression
  • Hexosamines / metabolism
  • Hydro-Lyases / chemistry
  • Hydro-Lyases / classification
  • Hydro-Lyases / genetics
  • Hydro-Lyases / metabolism
  • Kinetics
  • Molecular Sequence Data
  • N-Acetylneuraminic Acid / biosynthesis*
  • Oxo-Acid-Lyases / chemistry
  • Oxo-Acid-Lyases / genetics
  • Oxo-Acid-Lyases / metabolism*
  • Phylogeny
  • Pyruvic Acid / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Substrate Specificity

Substances

  • Bacterial Proteins
  • Hexosamines
  • Recombinant Proteins
  • Pyruvic Acid
  • Oxo-Acid-Lyases
  • Hydro-Lyases
  • 4-hydroxy-tetrahydrodipicolinate synthase
  • N-Acetylneuraminic Acid
  • N-acetylmannosamine