scholarly journals Synergistic Hydrolysis of Carboxymethyl Cellulose and Acid-Swollen Cellulose by Two Endoglucanases (CelZ and CelY) fromErwinia chrysanthemi

2000 ◽  
Vol 182 (20) ◽  
pp. 5676-5682 ◽  
Author(s):  
Shengde Zhou ◽  
Lonnie O. Ingram
Keyword(s):  
Carboxymethyl Cellulose ◽  
Cell Walls ◽  
Cellulase Activity ◽  
Substrate Preference ◽  
Erwinia Chrysanthemi ◽  
General Mechanism ◽  
Plant Cell Walls ◽  
Enzymatic Modification ◽  
Amorphous Cellulose ◽  
Hydrolysis Of

ABSTRACT Erwinia chrysanthemi produces a battery of hydrolases and lyases which are very effective in the maceration of plant cell walls. Although two endoglucanases (CelZ and CelY; formerly EGZ and EGY) are produced, CelZ represents approximately 95% of the total carboxymethyl cellulase activity. In this study, we have examined the effectiveness of CelY and CelZ alone and of combinations of both enzymes using carboxymethyl cellulose (CMC) and amorphous cellulose (acid-swollen cellulose) as substrates. Synergy was observed with both substrates. Maximal synergy (1.8-fold) was observed for combinations containing primarily CelZ; the ratio of enzyme activities produced was similar to those produced by cultures of E. chrysanthemi. CelY and CelZ were quite different in substrate preference. CelY was unable to hydrolyze soluble cellooligosaccharides (cellotetraose and cellopentaose) but hydrolyzed CMC to fragments averaging 10.7 glucosyl units. In contrast, CelZ readily hydrolyzed cellotetraose, cellopentaose, and amorphous cellulose to produce cellobiose and cellotriose as dominant products. CelZ hydrolyzed CMC to fragments averaging 3.6 glucosyl units. In combination, CelZ and CelY hydrolyzed CMC to products averaging 2.3 glucosyl units. Synergy did not require the simultaneous presence of both enzymes. Enzymatic modification of the substrate by CelY increased the rate and extent of hydrolysis by CelZ. Full synergy was retained by the sequential hydrolysis of CMC, provided CelY was used as the first enzyme. A general mechanism is proposed to explain the synergy between these two enzymes based primarily on differences in substrate preference.

Extracellular cellulase production by tropical isolates of Aureobasidium pullulans

2005 ◽  
Vol 51 (9) ◽  
pp. 773-776 ◽  
Author(s):  
T Kudanga ◽  
E Mwenje
Keyword(s):  
Carboxymethyl Cellulose ◽  
Cell Walls ◽  
Aureobasidium Pullulans ◽  
Plant Cell Wall ◽  
Synthetic Medium ◽  
Cellulase Activity ◽  
Nitrogen Sources ◽  
Cellulase Production ◽  
Cellulolytic Activity ◽  
Specific Activities

Cellulase production by Aureobasidium pullulans from the temperate regions has remained speculative, with most studies reporting no activity at all. In the current study, tropical isolates from diverse sources were screened for cellulase production. Isolates were grown on a synthetic medium containing cell walls of Msasa tree (Brachystegia sp.) as the sole carbon source, and their cellulolytic activities were measured using carboxymethyl cellulose and α-cellulose as substrates. All isolates studied produced carboxymethyl cellulase (endoglucanase) and alpha-cellulase (exoglucanase) activity. Endoglucanase-specific activities of ten selected isolates ranged from 2.375 to 12.884 µmol glucose·(mg protein)–1·h–1, while activities on α-cellulose (exoglucanase activity) ranged from 0.293 to 22.442 µmol glucose·(mg protein)–1·day–1. Carboxymethyl cellulose induced the highest cellulase activity in the selected isolates, while the isolates showed variable responses to nitrogen sources. The current study indicates that some isolates of A. pullulans of tropical origin produce significant extracellular cellulolytic activity and that crude cell walls may be good inducers of cellulolytic activity in A. pullulans.Key words: Aureobasidium pullulans, plant cell wall, cellulases, endoglucanase, exoglucanase.

Sorting out theLeMANs: endo-β-mannanase genes and their encoded proteins in tomato

2007 ◽  
Vol 17 (3) ◽  
pp. 143-154 ◽  
Author(s):  
Xuemei Gong ◽  
J. Derek Bewley
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Gibberellic Acid ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Tomato Seeds ◽  
C Terminus ◽  
Inactive Form ◽  
Genes Encoding ◽  
Hydrolysis Of

AbstractEndo-β-mannanase (EC 3.2.1.78) is involved in the hydrolysis of mannan-type polysaccharides that are present in plant cell walls, especially those of the seed endosperm. The genes encoding the endo-β-mannanases have been studied extensively in tomato (Solanum lycopersicum), and five genes (LeMAN1,LeMAN2,LeMAN3,LeMAN4andLeMAN5) and/or their products have been isolated and characterized.LeMAN1,LeMAN2andLeMAN3are expressed in tomato seeds,LeMAN4in the fruit andLeMAN5in the flower.LeMAN5andLeMAN2are now considered to be the same gene, and the former is re-designated asLeMAN2*. Transcripts ofLeMANs1, 2and3are detected only in the endosperm of tomato seeds, and their synthesis is promoted by gibberellic acid.LeMAN4, in the fruit, occurs asLeMAN4aandLeMAN4igenes that encode an active or inactive form of endo-β-mannanase, respectively.LeMAN1–4 enzymes encoded by these genes share 80% similarity in amino acid sequence. In tomato, the leucine amino acid present near to the C-terminus of the endo-β-mannanase is the most important for achieving full activity of the enzyme.

Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

2010 ◽  
Vol 38 (8) ◽  
pp. 975-983 ◽  
Author(s):  
Lisbeth Garbrecht Thygesen ◽  
Budi Juliman Hidayat ◽  
Katja Salomon Johansen ◽  
Claus Felby
Keyword(s):  
Enzymatic Hydrolysis ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Hydrolysis Of ◽  
Cellulose Structures

Structure of the oligogalacturonate-specific KdgM porin

2014 ◽  
Vol 70 (6) ◽  
pp. 1770-1778 ◽  
Author(s):  
C. A. J. Hutter ◽  
R. Lehner ◽  
Ch. Wirth ◽  
G. Condemine ◽  
C. Peneff ◽  
...  
Keyword(s):  
Cell Walls ◽  
Circular Cross Section ◽  
Erwinia Chrysanthemi ◽  
Plant Cell Walls ◽  
Negative Bacterium ◽  
Dickeya Dadantii ◽  
Outer Membrane Porin ◽  
Minimal Radius ◽  
Arginine Residues

The phytopathogenic Gram-negative bacteriumDickeya dadantii(Erwinia chrysanthemi) feeds on plant cell walls by secreting pectinases and utilizing the oligogalacturanate products. An outer membrane porin, KdgM, is indispensable for the uptake of these acidic oligosaccharides. Here, the crystal structure of KdgM determined to 1.9 Å resolution is presented. KdgM is folded into a regular 12-stranded antiparallel β-barrel with a circular cross-section defining a transmembrane pore with a minimal radius of 3.1 Å. Most of the loops that would face the cell exteriorin vivoare disordered, but nevertheless mediate contact between densely packed membrane-like layers in the crystal. The channel is lined by two tracks of arginine residues facing each other across the pore, a feature that is conserved within the KdgM family and is likely to facilitate the diffusion of acidic oligosaccharides.

scholarly journals Determination of glycoside hydrolase specificities during hydrolysis of plant cell walls using glycome profiling

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Johnnie A. Walker ◽  
Sivakumar Pattathil ◽  
Lai F. Bergeman ◽  
Emily T. Beebe ◽  
Kai Deng ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Glycoside Hydrolase ◽  
Plant Cell Walls ◽  
Glycome Profiling ◽  
Hydrolysis Of

Molecular dynamics of the Bacillus subtilis expansin EXLX1: interaction with substrates and structural basis of the lack of activity of mutants

2016 ◽  
Vol 18 (5) ◽  
pp. 3510-3521 ◽  
Author(s):  
Rodrigo L. Silveira ◽  
Munir S. Skaf
Keyword(s):  
Molecular Dynamics ◽  
Bacillus Subtilis ◽  
Enzymatic Hydrolysis ◽  
Plant Cell ◽  
Cell Walls ◽  
Structural Basis ◽  
Plant Cell Walls ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Expansins are disruptive proteins that loosen growing plant cell walls and can enhance the enzymatic hydrolysis of cellulose.

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

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