In silico mining and characterization of bifidobacterial lipoprotein with CHAP domain secreted in an aggregated form

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• 作者：Angelo Scuotto^a ; ^c ; ^{angelo.scuotto@live.fr" class="auth_mail" title="E-mail the corresponding author} ; Pierre-Charles Romond^b ; ^{p-charles.romond@udamail.fr" class="auth_mail" title="E-mail the corresponding author} ; Serge Djorie^b ; ^{djorie2000@yahoo.fr" class="auth_mail" title="E-mail the corresponding author} ; Monique Alric^b ; ^{monique.alric@udamail.fr" class="auth_mail" title="E-mail the corresponding author} ; Marie-Bé ; né ; dicte Romond^a ; ^{marie-benedicte.romond@univ-lille2.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：BC ; bifidobacterial compounds of high molecular weight ; HM mice ; descents of gnotobiotic mice associated with human healthy volunteer microbiota ; RA mice ; descents of gnotobiotic mice associated with human rheumatoid arthritis microbiota ; CHAP domain ; cysteine ; histidine-dependent amidohydrolases/peptidases domain ; GF ; gel filtration
• 刊名：International Journal of Biological Macromolecules
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：82
• 期：Complete
• 页码：653-662
• 全文大小：1133 K

文摘

Bifidobacterium breve C50 secretes a lipoprotein associated with glucose, acting in an aggregating form (>600 kDa) as an agonist of TLR2/6. Similar lipoproteins were sought for in bifidobacteria. In silico, the closest homology was shown with a Bifidobacterium longum protein containing CHAP and lipobox domains. Two strains secreted aggregates whose peptides sequences aligned with the mined protein. C16:0 and C18:0 fatty acids detected in the aggregates further supported a lipoprotein structure. Glucose and mannose detected by gas chromatography were likely ligands of the lipoprotein. The binding of aggregates to galectin-1 indicated that hexosamines and galactose surrounded them. However, unlike B. breve C50, aggregate secreted by B. longum CBi0703 was unable to bind TLR2/6 likely because of a more hydrophobic structure. In gnotobiotic mice, the intake of B. longum aggregate induced, in splenic dendritic cells, the expression of genes involved in antigen presentation. A positive correlation between the number of dendritic cells and CD4⁺CD25⁺ cells was observed in mice receiving these aggregates. In conclusion, B. longum secretes a lipoprotein forming aggregates which may influence dendritic and CD4⁺CD25⁺ cell interactions independently of the TLR2/6 pathway.