Crystal structures of glycoside hydrolase family 136 lacto-N-biosidases from monkey gut- and human adult gut bacteria. Issue 4 (29th January 2022)

• Record Type: Journal Article
• Authors: Yamada, Chihaya; Katayama, Takane; Fushinobu, Shinya
• Is Part Of: Bioscience, biotechnology, and biochemistry. Volume 86:Issue 4(2022)
• Page Start: 464
• Page End: 475
• Publication Date: 2022-01-29
• Subjects: lacto-N-biosidase -- glycoside hydrolase family 136 -- human milk oligosaccharides -- lacto-N-biose I -- human gut microbiota; Biotechnology -- Periodicals; Biochemistry -- Periodicals; 660.6
• DOI: 10.1093/bbb/zbac015
• Languages: English
• ISSNs: 0916-8451

Abstract

ABSTRACT: Glycoside hydrolase family 136 (GH136) was established after the discovery and structural analysis of lacto- N -biosidase (LNBase) from the infant gut bacterium Bifidobacterium longum subsp. longum JCM1217 ( Bl LnbX). Homologous genes of Bl LnbX are widely distributed in the genomes of human gut bacteria and monkey Bifidobacterium spp., although only 2 crystal structures were reported in the GH136 family. Cell suspensions of Bifidobacterium saguini, Tyzzerella nexilis, and Ruminococcus lactaris exhibited the LNBase activity. Recombinant LNBases of these 3 species were functionally expressed with their specific chaperones in Escherichia coli, and their kinetic parameters against p -nitrophenol substrates were determined. The crystal structures of the LNBases from B. saguini and T. nexilis in complex with lacto- N -biose I were determined at 2.51 and 1.92 Å resolutions, respectively. These structures conserve a β-helix fold characteristic of GH136 and the catalytic residues, but they lack the metal ions that were present in Bl LnbX. Graphical Abstract: