Biochemical Characterization and Synthetic Application of WciN and Its Mutants From Streptococcus pneumoniae Serotype 6B

Wei Gong; Min Liang; Jielin Zhao; Hong Wang; Zonggang Chen; Fengshan Wang; Guofeng Gu

doi:10.3389/fchem.2022.914698

Biochemical Characterization and Synthetic Application of WciN and Its Mutants From Streptococcus pneumoniae Serotype 6B

Front Chem. 2022 Jun 15:10:914698. doi: 10.3389/fchem.2022.914698. eCollection 2022.

Authors

Wei Gong^{1

2}, Min Liang^{1

3}, Jielin Zhao^{1

3}, Hong Wang^{1

3}, Zonggang Chen^{1

3}, Fengshan Wang^{1

2

3}, Guofeng Gu^{1

3}

Affiliations

¹ National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China.
² School of Pharmaceutical Science, Shandong University, Jinan, China.
³ NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China.

Abstract

The biochemical properties of α-1,3-galactosyltransferase WciN from Streptococcus pneumoniae serotype 6B were systemically characterized with the chemically synthesized Glcα-PP-(CH₂)₁₁-OPh as an acceptor substrate. The in vitro site-directed mutation of D38 and A150 residues of WciN was further investigated, and the enzymatic activities of those WciN mutants revealed that A150 residue was the pivotal residue responsible for nucleotide donor recognition and the single-site mutation could completely cause pneumococcus serotype switch. Using WciN_A150P and WciN_A150D mutants as useful tool enzymes, the disaccharides Galα1,3Glcα-PP-(CH₂)₁₁-OPh and Glcα1,3Glcα-PP-(CH₂)₁₁-OPh were successfully prepared in multi-milligram scale in high yields.

Keywords: Streptococcus pneumoniae serotype 6B; capsular polysaccharides; enzymatic synthesis; galactosyltransferase; site mutation.