scholarly journals Cloning, Expression and Characterization of a Novel Cold-adapted β-galactosidase from the Deep-sea Bacterium Alteromonas sp. ML52

Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 469 ◽  
Author(s):  
Jingjing Sun ◽  
Congyu Yao ◽  
Wei Wang ◽  
Zhiwei Zhuang ◽  
Junzhong Liu ◽  
...  

The bacterium Alteromonas sp. ML52, isolated from deep-sea water, was found to synthesize an intracellular cold-adapted β-galactosidase. A novel β-galactosidase gene from strain ML52, encoding 1058 amino acids residues, was cloned and expressed in Escherichia coli. The enzyme belongs to glycoside hydrolase family 2 and is active as a homotetrameric protein. The recombinant enzyme had maximum activity at 35 °C and pH 8 with a low thermal stability over 30 °C. The enzyme also exhibited a Km of 0.14 mM, a Vmax of 464.7 U/mg and a kcat of 3688.1 S−1 at 35 °C with 2-nitrophenyl-β-d-galactopyranoside as a substrate. Hydrolysis of lactose assay, performed using milk, indicated that over 90% lactose in milk was hydrolyzed after incubation for 5 h at 25 °C or 24 h at 4 °C and 10 °C, respectively. These properties suggest that recombinant Alteromonas sp. ML52 β-galactosidase is a potential biocatalyst for the lactose-reduced dairy industry.

2021 ◽  
Author(s):  
Gregory S Bulmer ◽  
Fang Wei Yuen ◽  
Naimah Begum ◽  
Bethan S Jones ◽  
Sabine S Flitsch ◽  
...  

β-D-Galactofuranose (Galf) and its polysaccharides are found in bacteria, fungi and protozoa but do not occur in mammalian tissues, and thus represent a specific target for anti-pathogenic drugs. Understanding the enzymatic degradation of these polysaccharides is therefore of great interest, but the identity of fungal enzymes with exclusively galactofuranosidase activity has so far remained elusive. Here we describe the identification and characterization of a galactofuranosidase from the industrially important fungus Aspergillus niger. Phylogenetic analysis of glycoside hydrolase family 43 subfamily 34 (GH43_34) members revealed the occurrence of three distinct clusters and, by comparison with specificities of characterized bacterial members, suggested a basis for prediction of enzyme specificity. Using this rationale, in tandem with molecular docking, we identified a putative β-D-galactofuranosidase from A. niger which was recombinantly expressed in Escherichia coli. The Galf-specific hydrolase, encoded by xynD demonstrates maximum activity at pH 5, 25 °C towards 4-Nitrophenyl-β-galactofuranoside (pNP-βGalf), with a Km of 17.9 ± 1.9 mM and Vmax of 70.6 ± 5.3 μmol min-1. The characterization of this first fungal GH43 galactofuranosidase offers further molecular insight into the degradation of Galf-containing structures and may inform clinical treatments against fungal pathogens.


2005 ◽  
Vol 388 (3) ◽  
pp. 949-957 ◽  
Author(s):  
Masashi KIYOHARA ◽  
Keishi SAKAGUCHI ◽  
Kuniko YAMAGUCHI ◽  
Toshiyoshi ARAKI ◽  
Takashi NAKAMURA ◽  
...  

We cloned a novel β-1,3-xylanase gene, consisting of a 1728-bp open reading frame encoding 576 amino acid residues, from a marine bacterium, Vibrio sp. strain AX-4. Sequence analysis revealed that the β-1,3-xylanase is a modular enzyme composed of a putative catalytic module belonging to glycoside hydrolase family 26 and two putative carbohydrate-binding modules belonging to family 31. The recombinant enzyme hydrolysed β-1,3-xylan to yield xylo-oligosaccharides with different numbers of xylose units, mainly xylobiose, xylotriose and xylotetraose. However, the enzyme did not hydrolyse β-1,4-xylan, β-1,4-mannan, β-1,4-glucan, β-1,3-xylobiose or p-nitrophenyl-β-xyloside. When β-1,3-xylo-oligosaccharides were used as the substrate, the kcat value of the enzyme for xylopentaose was found to be 40 times higher than that for xylotetraose, and xylotriose was extremely resistant to hydrolysis by the enzyme. A PSI-BLAST search revealed two possible catalytic Glu residues (Glu-138 as an acid/base catalyst and Glu-234 as a nucleophile), both of which are generally conserved in glycoside hydrolase superfamily A. Replacement of these two conserved Glu residues with Asp and Gln resulted in a significant decrease and complete loss of enzyme activity respectively, without a change in their CD spectra, suggesting that these Glu residues are the catalytic residues of β-1,3-xylanase. The present study also clearly shows that the non-catalytic putative carbohydrate-binding modules play an important role in the hydrolysis of insoluble β-1,3-xylan, but not that of soluble glycol-β-1,3-xylan. Furthermore, repeating a putative carbohydrate-binding module strongly enhanced the hydrolysis of the insoluble substrate.


Microbiology ◽  
2012 ◽  
Vol 158 (8) ◽  
pp. 2168-2179 ◽  
Author(s):  
Jolanda M. van Munster ◽  
Rachel M. van der Kaaij ◽  
Lubbert Dijkhuizen ◽  
Marc J. E. C. van der Maarel

2004 ◽  
Vol 66 (3) ◽  
pp. 266-275 ◽  
Author(s):  
Yukari Ohta ◽  
Yuji Hatada ◽  
Yuichi Nogi ◽  
Zhijun Li ◽  
Susumu Ito ◽  
...  

2010 ◽  
Vol 9 (11) ◽  
pp. 1650-1660 ◽  
Author(s):  
Encarnación Dueñas-Santero ◽  
Ana Belén Martín-Cuadrado ◽  
Thierry Fontaine ◽  
Jean-Paul Latgé ◽  
Francisco del Rey ◽  
...  

ABSTRACT In yeast, enzymes with β-glucanase activity are thought to be necessary in morphogenetic events that require controlled hydrolysis of the cell wall. Comparison of the sequence of the Saccharomyces cerevisiae exo-β(1,3)-glucanase Exg1 with the Schizosaccharomyces pombe genome allowed the identification of three genes that were named exg1 + (locus SPBC1105.05), exg2 + (SPAC12B10.11), and exg3 + (SPBC2D10.05). The three proteins have different localizations: Exg1 is secreted to the periplasmic space, Exg2 is a membrane protein, and Exg3 is a cytoplasmic protein. Characterization of the biochemical activity of the proteins indicated that Exg1 and Exg3 are active only against β(1,6)-glucans while no activity was detected for Exg2. Interestingly, Exg1 cleaves the glucans with an endohydrolytic mode of action. exg1 + showed periodic expression during the cell cycle, with a maximum coinciding with the septation process, and its expression was dependent on the transcription factor Sep1. The Exg1 protein localizes to the septum region in a pattern that was different from that of the endo-β(1,3)-glucanase Eng1. Overexpression of Exg2 resulted in an increase in cell wall material at the poles and in the septum, but the putative catalytic activity of the protein was not required for this effect.


2007 ◽  
Vol 73 (9) ◽  
pp. 3109-3112 ◽  
Author(s):  
Tatsuji Sakamoto ◽  
Yuya Taniguchi ◽  
Shiho Suzuki ◽  
Hideshi Ihara ◽  
Haruhiko Kawasaki

ABSTRACT A type II arabinogalactan-degrading enzyme (FoGal1) was purified from Fusarium oxysporum 12S, and the corresponding cDNA was isolated. FoGal1 had high similarity to enzymes of glycoside hydrolase family 5. Treatment of larch wood arabinogalactan with the recombinant enzyme indicated that FoGal1 is a β-1,6-galactanase that preferentially debranches β-1,6-galactobiose from the substrate.


2018 ◽  
Vol 37 (5) ◽  
pp. 454-460
Author(s):  
Carola Schröder ◽  
Christin Burkhardt ◽  
Philip Busch ◽  
Georg Schirrmacher ◽  
Jörg Claren ◽  
...  

Author(s):  
Kurt Wagschal ◽  
Diana Franqui-Espiet ◽  
Charles C. Lee ◽  
George H. Robertson ◽  
Dominic W. S. Wong

Sign in / Sign up

Export Citation Format

Share Document