Dataset Information

Characterization of the First ?-(1?3) Branching Sucrases of the GH70 Family.

ABSTRACT: Leuconostoc citreumNRRL B-742 has been known for years to produce a highly ?-(1?3)-branched dextran for which the synthesis had never been elucidated. In this work a gene coding for a putative ?-transglucosylase of the GH70 family was identified in the reported genome of this bacteria and functionally characterized. From sucrose alone, the corresponding recombinant protein, named BRS-B, mainly catalyzed sucrose hydrolysis and leucrose synthesis. However, in the presence of sucrose and a dextran acceptor, the enzyme efficiently transferred the glucosyl residue from sucrose to linear ?-(1?6) dextrans through the specific formation of ?-(1?3) linkages. To date, BRS-B is the first reported ?-(1?3) branching sucrase. Using a suitable sucrose/dextran ratio, a comb-like dextran with 50% of ?-(1?3) branching was synthesized, suggesting that BRS-B is likely involved in the comb-like dextran produced byL. citreumNRRL B-742. In addition, data mining based on the search for specific sequence motifs allowed the identification of two genes putatively coding for branching sucrases in the genome ofLeuconostoc fallaxKCTC3537 andLactobacillus kunkeeiEFB6. Biochemical characterization of the corresponding recombinant enzymes confirmed their branching specificity, revealing that branching sucrases are not only found inL. citreumspecies. According to phylogenetic analyses, these enzymes are proposed to constitute a new subgroup of the GH70 family.

SUBMITTER: Vuillemin M

PROVIDER: S-EPMC4817194 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Characterization of the First α-(1→3) Branching Sucrases of the GH70 Family.

Vuillemin Marlène M Claverie Marion M Brison Yoann Y Séverac Etienne E Bondy Pauline P Morel Sandrine S Monsan Pierre P Moulis Claire C Remaud-Siméon Magali M

The Journal of biological chemistry 20160113 14

Leuconostoc citreumNRRL B-742 has been known for years to produce a highly α-(1→3)-branched dextran for which the synthesis had never been elucidated. In this work a gene coding for a putative α-transglucosylase of the GH70 family was identified in the reported genome of this bacteria and functionally characterized. From sucrose alone, the corresponding recombinant protein, named BRS-B, mainly catalyzed sucrose hydrolysis and leucrose synthesis. However, in the presence of sucrose and a dextran ...[more]

PMID: 26763236

Similar Datasets

Project description:Glucansucrases (GSs) in glycoside hydrolase family 70 (GH70) catalyze the synthesis of ?-glucans from sucrose, a reaction that is widely seen in lactic acid bacteria (LAB). These enzymes have been implicated in many aspects of microbial life. Products of GSs have great commercial value as food supplements and medical materials; therefore, these enzymes have attracted much attention from both science and industry. Certain issues concerning the origin and evolution of GSs are still to be addressed, although an increasing number of GH70 enzymes have been characterized. This study describes a GS enzyme with the appearance of a branching sucrase (BrS). Structural analysis indicated that this GS enzyme produced a type of glucan composed of an ?-(1?6) glucosidic backbone and ?-(1?4) branches, as well as a considerable amount of ?-(1?3) branches, distinguishing it from the GSs identified so far. Moreover, sequence-based analysis of the catalytic core of this enzyme suggested that it might be an evolutionary intermediate between the BrS and GS subgroups. These results provide an evolutionary link between these subgroups of GH70 enzymes and shed new light on the origination of GSs.IMPORTANCE GH70 GSs catalyze the synthesis of ?-glucans from sucrose, a reaction that is widely seen in LAB. Products of these enzymes have great commercial value as food supplements and medical materials. Moreover, these enzymes have attracted much attention from scientists because they have potential in tailored synthesis of ?-glucans with desired structures and properties. Although more and more GSs have been characterized, the origin and evolution of these enzymes have not been well addressed. This study describes a GS with the appearance of a BrS (i.e., high levels of similarity to BrSs in sequence analysis). Further analysis indicated that this enzyme synthesized a type of insoluble glucan composed of an ?-(1?6) glucosidic backbone and many ?-(1?4)- and ?-(1?3)-linked branches, the linkage composition of which has rarely been reported in the literature. This BrS-like GS enzyme might be an evolutionary intermediate between BrS and GS enzymes.

Project description:Microbes trapped in permanently frozen paleosoils (permafrost) are the focus of increasing research in the context of global warming. Our previous investigations led to the discovery and reactivation of two Acanthamoeba-infecting giant viruses, Mollivirus sibericum and Pithovirus sibericum, from a 30,000-year old permafrost layer. While several modern pithovirus strains have since been isolated, no contemporary mollivirus relative was found. We now describe Mollivirus kamchatka, a close relative to M. sibericum, isolated from surface soil sampled on the bank of the Kronotsky River in Kamchatka, Russian Federation. This discovery confirms that molliviruses have not gone extinct and are at least present in a distant subarctic continental location. This modern isolate exhibits a nucleocytoplasmic replication cycle identical to that of M. sibericum Its spherical particle (0.6 μm in diameter) encloses a 648-kb GC-rich double-stranded DNA genome coding for 480 proteins, of which 61% are unique to these two molliviruses. The 461 homologous proteins are highly conserved (92% identical residues, on average), despite the presumed stasis of M. sibericum for the last 30,000 years. Selection pressure analyses show that most of these proteins contribute to virus fitness. The comparison of these first two molliviruses clarify their evolutionary relationship with the pandoraviruses, supporting their provisional classification in a distinct family, the Molliviridae, pending the eventual discovery of intermediary missing links better demonstrating their common ancestry.IMPORTANCE Virology has long been viewed through the prism of human, cattle, or plant diseases, leading to a largely incomplete picture of the viral world. The serendipitous discovery of the first giant virus visible under a light microscope (i.e., >0.3 μm in diameter), mimivirus, opened a new era of environmental virology, now incorporating protozoan-infecting viruses. Planet-wide isolation studies and metagenome analyses have shown the presence of giant viruses in most terrestrial and aquatic environments, including upper Pleistocene frozen soils. Those systematic surveys have led authors to propose several new distinct families, including the Mimiviridae, Marseilleviridae, Faustoviridae, Pandoraviridae, and Pithoviridae We now propose to introduce one additional family, the Molliviridae, following the description of M. kamchatka, the first modern relative of M. sibericum, previously isolated from 30,000-year-old arctic permafrost.

Dataset Information

Characterization of the First ?-(1?3) Branching Sucrases of the GH70 Family.

Publications

Characterization of the First α-(1→3) Branching Sucrases of the GH70 Family.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets