scholarly journals Biochemical characterization of a novel ulvan lyase from Pseudoalteromonas sp. strain PLSV

RSC Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 2610-2615 ◽  
Author(s):  
Hui-Min Qin ◽  
Panpan Xu ◽  
Qianqian Guo ◽  
Xiaotao Cheng ◽  
Dengke Gao ◽  
...  

Ulvans, complex polysaccharides found in the ulvales (green seaweed) cell wall, contain predominantly 3-sulfated rhamnose (Rha3S) linked to either d-glucuronic acid, l-iduronic acid or d-xylose.

1976 ◽  
Vol 22 (7) ◽  
pp. 1007-1012 ◽  
Author(s):  
Susanne M. Pearce

Previous studies on this cortexless mutant of Bacillus cereus var. alesti indicated that the forespore membrane was the site of the biochemical lesion. This hypothesis is supported by the results presented here: fatty acid composition of sporulating cells of the mutant is altered, while in vegetative cells it is comparable to the parent; soluble precursors of peptidoglycan synthesis are accumulated in the mutant, at the time of cortex formation; homogenates of the mutant prepared at the time of cortex formation are unable to incorporate tritiated diaminopimelic acid into peptidoglycan, while homogenates of cells forming germ cell wall do so to an extent comparable to that of the parent; lipid-linked intermediates are formed by the mutant as in the parent. Apparently the mutant is unable either to transfer disaccharide penta-peptide units from the carrier lipid to the growing peptidoglycan acceptor, or to transport lipid-linked intermediates across the forespore membrane.


2012 ◽  
Vol 87 (2) ◽  
pp. 1219-1223 ◽  
Author(s):  
Raquel da Silva Aires ◽  
Andrei Stecca Steindorff ◽  
Marcelo Henrique Soller Ramada ◽  
Saulo José Linhares de Siqueira ◽  
Cirano José Ulhoa

2018 ◽  
Vol 21 (1) ◽  
pp. 1303-1310 ◽  
Author(s):  
Tabussam Tufail ◽  
Farhan Saeed ◽  
Muhammad Imran ◽  
Muhammad Umair Arshad ◽  
Faqir Muhammad Anjum ◽  
...  

2007 ◽  
Vol 405 (1) ◽  
pp. 123-130 ◽  
Author(s):  
Erin L. Westman ◽  
David J. Mcnally ◽  
Martin Rejzek ◽  
Wayne L. Miller ◽  
Vellupillai Sri Kannathasan ◽  
...  

The heteropolymeric O-antigen of the lipopolysaccharide from Pseudomonas aeruginosa serogroup O5 as well as the band-A trisaccharide from Bordetella pertussis contain the di-N-acetylated mannosaminuronic acid derivative, β-D-ManNAc3NAcA (2,3-diacetamido-2,3-dideoxy-β-D-mannuronic acid). The biosynthesis of the precursor for this sugar is proposed to require five steps, through which UDP-α-D-GlcNAc (UDP-N-acetyl-α-D-glucosamine) is converted via four steps into UDP-α-D-GlcNAc3NAcA (UDP-2,3-diacetamido-2,3-dideoxy-α-D-glucuronic acid), and this intermediate compound is then epimerized by WbpI (P. aeruginosa), or by its orthologue, WlbD (B. pertussis), to form UDP-α-D-ManNAc3NAcA (UDP-2,3-diacetamido-2,3-dideoxy-α-D-mannuronic acid). UDP-α-D-GlcNAc3NAcA, the proposed substrate for WbpI and WlbD, was obtained through chemical synthesis. His6–WbpI and His6–WlbD were overexpressed and then purified by affinity chromatography using FPLC. Capillary electrophoresis was used to analyse reactions with each enzyme, and revealed that both enzymes used UDP-α-D-GlcNAc3NAcA as a substrate, and reacted optimally in sodium phosphate buffer (pH 6.0). Neither enzyme utilized UDP-α-D-GlcNAc, UDP-α-D-GlcNAcA (UDP-2-acetamido-2,3-dideoxy-α-D-glucuronic acid) or UDP-α-D-GlcNAc3NAc (UDP-2,3-diacetamido-2,3-dideoxy-α-D-glucose) as substrates. His6–WbpI or His6–WlbD reactions with UDP-α-D-GlcNAc3NAcA produce a novel peak with an identical retention time, as shown by capillary electrophoresis. To unambiguously characterize the reaction product, enzyme–substrate reactions were allowed to proceed directly in the NMR tube and conversion of substrate into product was monitored over time through the acquisition of a proton spectrum at regular intervals. Data collected from one- and two-dimensional NMR experiments showed that His6–WbpI catalysed the 2-epimerization of UDP-α-D-GlcNAc3NAcA, converting it into UDP-α-D-ManNAc3NAcA. Collectively, these results provide evidence that WbpI and WlbD are UDP-2,3-diacetamido-2,3-dideoxy-α-D-glucuronic acid 2-epimerases.


PLoS ONE ◽  
2012 ◽  
Vol 7 (2) ◽  
pp. e31588 ◽  
Author(s):  
Ingmar J. J. Claes ◽  
Geert Schoofs ◽  
Krzysztof Regulski ◽  
Pascal Courtin ◽  
Marie-Pierre Chapot-Chartier ◽  
...  

1974 ◽  
Vol 143 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Lars-Åke Fransson ◽  
Lars Cöster ◽  
Anders Malmström ◽  
Ingrid Sjöberg

Selective periodate oxidation of unsubstituted l-iduronic acid residues in copolymeric dermatan sulphate chains was followed by reduction-hydrolysis or alkaline elimination. By this procedure the glucuronic acid-containing periods were isolated in oligosaccharide form; general formula: [Formula: see text] Further degradation of these oligosaccharides with chondroitinase-AC yielded three types of products: (a) sulphated trisaccharide containing an unsaturated uronosyl moiety in the non-reducing terminal and a C4 fragment in the reducing terminal, ΔUA-GalNAc-(-SO4)-R; (b) monosulphated, unsaturated disaccharide, ΔUA-GalNAc-SO4 when n is greater than or equal to 2; and (c) N-acetylgalactosamine with or without sulphate. Oligosaccharides containing a single glucuronic acid residue (n=1) comprised more than half of the glucuronic acid-containing oligosaccharides. The terminal N-acetylgalactosamine moiety of the shortest oligosaccharide was largely 4-sulphated, whereas higher oligosaccharides primarily contained 6-sulphated or unsulphated hexosamine moieties in the same position. Moreover, IdUA-SO4-containing oligosaccharides were encountered. These oligosaccharides were resistant to the action of chondroitinase-ABC.


2006 ◽  
Vol 19 (6) ◽  
pp. 625-634 ◽  
Author(s):  
Ralf T. Voegele ◽  
Stefan Wirsel ◽  
Ulla Möll ◽  
Melanie Lechner ◽  
Kurt Mendgen

Invertases are key enzymes in carbon partitioning in higher plants. They gain additional importance in the distribution of carbohydrates in the event of wounding or pathogen attack. Although many researchers have found an increase in invertase activity upon infection, only a few studies were able to determine whether the source of this activity was host or parasite. This article analyzes the role of invertases involved in the biotrophic interaction of the rust fungus Uromyces fabae and its host plant, Vicia faba. We have identified a fungal gene, Uf-INV1, with homology to invertases and assessed its contribution to pathogenesis. Expression analysis indicated that transcription began upon penetration of the fungus into the leaf, with high expression levels in haustoria. Heterologous expression of Uf-INV1 in Saccharomyces cerevisiae and Pichia pastoris allowed a biochemical characterization of the enzymatic activity associated with the secreted gene product INV1p. Expression analysis of the known vacuolar and cell-wall-bound invertase isoforms of V. faba indicated a decrease in the expression of a vacuolar invertase, whereas one cell-wall-associated invertase exhibited increased expression. These changes were not confined to the infected tissue, and effects also were observed in remote plant organs, such as roots. These findings hint at systemic effects of pathogen infection. Our results support the hypothesis that pathogen infection establishes new sinks which compete with physiological sink organs.


Author(s):  
Tabussam Tufail ◽  
Farhan Saeed ◽  
Imran Pasha ◽  
Muhammad Umair Arshad ◽  
Muhammad Afzaal ◽  
...  

2020 ◽  
Vol 21 (9) ◽  
pp. 3380 ◽  
Author(s):  
Luis Morales-Quintana ◽  
Dina Beltrán ◽  
Ángela Mendez-Yañez ◽  
Felipe Valenzuela-Riffo ◽  
Raúl Herrera ◽  
...  

Xyloglucan endotransglycosylase/hydrolases (XTHs) are cell wall enzymes with hydrolase (XEH) and/or endotransglycosylase (XET) activities. As they are involved in the modification of the xyloglucans, a type of hemicellulose present in the cell wall, they are believed to be very important in different processes, including growth, development, and fruit ripening. Previous studies suggest that XTHs might play a key role in development and ripening of Fragaria chiloensis fruit, and its characterization is pending. Therefore, in order to provide a biochemical characterization of the FcXTH2 enzyme to explain its possible role in strawberry development, the molecular cloning and the heterologous expression of FcXTH2 were performed. The recombinant FcXTH2 was active and displayed mainly XEH activity. The optimal pH and temperature are 5.5 and 37 °C, respectively. A KM value of 0.029 mg mL−1 was determined. Additionally, its protein structural model was built through comparative modeling methodology. The model showed a typically β-jelly-roll type folding in which the catalytic motif was oriented towards the FcXTH2 central cavity. Using molecular docking, protein-ligand interactions were explored, finding better interaction with xyloglucan than with cellulose. The data provided groundwork for understanding, at a molecular level, the enzymatic mechanism of FcXTH2, an important enzyme acting during the development of the Chilean strawberry.


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