Journal ArticleDOI
A cryptic melibiose transporter gene possessing a frameshift from Citrobacter freundii.
Toshi Shimamoto,Tadashi Shimamoto,Xing-Jue Xu,Noriko Okazaki,Hideyuki Kawakami,Tomofusa Tsuchiya +5 more
TLDR
The cloned melB gene is closely similar to the melB genes of other bacteria, but it is cryptic because of a frameshift mutation and the amino acid sequence of the C. freundii MelB was found to be most similar to those of Salmonella typhimurium and Escherichia coli MelB.Abstract:
Wild-type Citrobacter freundii cannot grow on melibiose as a sole source of carbon. The melibiose transporter gene melB was cloned from a C. freundii mutant M4 that could utilize melibiose as a sole carbon source. Although the cloned melB gene is closely similar to the melB genes of other bacteria, it is cryptic because of a frameshift mutation. Site-directed mutagenesis was used to construct a functional melB gene by deleting one nucleotide, resulting in the production of an active melibiose transporter. The active MelB transporter could utilize Na(+) and H(+) as coupling cations to melibiose transport. The amino acid sequence of the C. freundii MelB was found to be most similar to those of Salmonella typhimurium and Escherichia coli MelB. These facts are consistent with the phylogenetic relationship of bacteria and the cation coupling properties of the melibiose transporters.read more
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Journal ArticleDOI
Galacto-oligosaccharides and colorectal cancer: Feeding our intestinal probiome
TL;DR: This review summarizes research on prebiotics bioassimilation, specifically β (1-4) GOS, and their potential role in CRC, and evaluates research that show that the impact of prebiotic on host physiology can be direct or through modulation of the gut intestinal microbiome.
Journal ArticleDOI
Characterization of the melA Locus for α-Galactosidase in Lactobacillus plantarum
Aurelio Silvestroni,Cristelle Connes,Fernando Sesma,Graciela Savoy de Giori,Jean-Christophe Piard +4 more
TL;DR: This first genetic characterization of melA and of its putative associated transporter, rafP, in a lactobacillus opens doors to various applications both in the manufacture of soy-derived products and in probiotic and nutraceutical issues.
Journal ArticleDOI
Metabolism of Four α-Glycosidic Linkage-Containing Oligosaccharides by Bifidobacterium breve UCC2003
Kerry Joan O'Connell,Mary O'Connell Motherway,John O'Callaghan,John O'Callaghan,Gerald F. Fitzgerald,R. Paul Ross,R. Paul Ross,Marco Ventura,Catherine Stanton,Catherine Stanton,Douwe van Sinderen +10 more
TL;DR: It is demonstrated that all B. breve strains examined possess the ability to utilize raffinose, stachyose, and melibiose, however, the able to metabolize melezitose was not common to all B-breve strains tested.
Book ChapterDOI
Mechanisms of protein evolution and their application to protein engineering.
TL;DR: Two evolutionary concepts that could provide a rational basis for template selection are the conservation of catalytic mechanisms and functional promiscuity and future research will determine if application of these principles will lead to a protein engineering methodology governed by predictable rules for designing efficient, novel catalysts.
Journal ArticleDOI
Hooked on α-d-galactosidases: from biomedicine to enzymatic synthesis.
TL;DR: A comprehensive general survey of α-d-galactosidases from different origin with special emphasis on marine example(s), with an emphasis on alternative selectivity of this class of enzymes from different sources is depicted.