Details

Autor(en) / Beteiligte

• Yamada, Chihaya
• Gotoh, Aina
• Sakanaka, Mikiyasu
• Hattie, Mitchell
• Stubbs, Keith A.
• Katayama-Ikegami, Ayako
• Hirose, Junko
• Kurihara, Shin
• Arakawa, Takatoshi
• Kitaoka, Motomitsu
• Okuda, Shujiro
• Katayama, Takane
• Fushinobu, Shinya

Titel

Molecular Insight into Evolution of Symbiosis between Breast-Fed Infants and a Member of the Human Gut Microbiome Bifidobacterium longum

Ist Teil von

• Cell chemical biology, 2017-04, Vol.24 (4), p.515-524.e5

Ort / Verlag

United States: Elsevier Ltd

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• Breast-fed infants generally have a bifidobacteria-rich microbiota with recent studies indicating that human milk oligosaccharides (HMOs) selectively promote bifidobacterial growth. Bifidobacterium bifidum possesses a glycoside hydrolase family 20 lacto-N-biosidase for liberating lacto-N-biose I from lacto-N-tetraose, an abundant HMO unique to human milk, while Bifidobacterium longum subsp. longum has a non-classified enzyme (LnbX). Here, we determined the crystal structure of the catalytic domain of LnbX and provide evidence for creation of a novel glycoside hydrolase family, GH136. The structure, in combination with inhibition and mutation studies, provides insight into the molecular mechanism and broader substrate specificity of this enzyme. Moreover, through genetic studies, we show that lnbX is indispensable for B. longum growth on lacto-N-tetraose and is a key genetic factor for persistence in the gut of breast-fed infants. Overall, this study reveals possible evolutionary routes for the emergence of symbiosis between humans and bifidobacterial species in the infant gut. [Display omitted] •Crystal structure of a new lacto-N-biosidase (LnbX) from B. longum is presented•The mechanism of LnbX is distinct from the lacto-N-biosidase of B. bifidum•lnbX is indispensable for growth and occupancy in the breast-fed infant gut•Host and microbe symbiotic and co-evolutionary relationships are revealed Human milk oligosaccharides selectively promote bifidobacterial growth in the infant gut. Yamada et al. provide the structural basis of lacto-N-biosidase (LnbX), a key enzymatic factor for growth and proliferation of B. longum in breast-fed infants. Possible evolutionary routes for the emergence of symbiosis between humans and bifidobacteria are revealed.