Agal, the first alpha-Galactosidase from the human bacteria Ruminococcus gnavus El, efficiently transcribed in gut conditions

作者：Aguilera Margarita; Rakotoarivonina Harivony; Brutus Alexandre; Giardina Thierry; Simon Gwenola; Fons Michel^*

来源：Research in Microbiology, 2012, 163(1): 14-21.

DOI：10.1016/j.resmic.2011.10.005

• Gut microbiota
• Ruminococcus gnavus
• Alpha-Galactosidase
• In vivo expression
• mRNA fingerprints

Differential gene expression analysis was performed in monoxenic mice colonized with Ruminococcus gnavus strain El, a major endogenous member of the gut microbiota. RNA arbitrarily primed-PCR fingerprinting assays allowed to specifically detect the in vivo expression of the agal gene, which was further confirmed by RT-PCR. The agal gene encoded a protein of 744 residues with calculated molecular mass of 85,207 Da. Agal exhibited significant similarity with previously characterized alpha-Galactosidases of the GH 36 family. Purified recombinant protein demonstrated high catalytic activity (104 +/- 7 U mg(-1)) and efficient p-nitrophenyl-alpha-D-galactopyranoside hydrolysis [k(cat)/K-m = 35.115 +/- 8.82 s(-1) mM(-1) at 55 degrees C and k(cat)/K-m = 17.48 +/- 4.25 s(-1) mM(-1) at 37 degrees C].

• 出版日期2012-1