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Rabinovich, M. A.; Melnick, M S; Bolobova, A. V.

doi:10.1023/a:1019958419032

Cited by 133 publications

(56 citation statements)

References 44 publications

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“…These observations may be explained by the recalcitrant nature of the cellulose microfibril. Unlike many cellulases involved in cellulose degradation, BcsZ lacks a carbohydrate binding domain to anchor it to the cellulose microfibril and increase its effectiveness (10). Hence, it is conceivable that BcsZ performs its biological function prior to the formation of the inert cellulose microfibril.…”

Section: Discussionmentioning

confidence: 99%

“…GH-8 enzymes hydrolyze glycosidic bonds with a pair of acidic residues in a reaction that inverts the anomeric configuration at the new reducing end (inverting hydrolases) (10). Studies with the Acetobacter xylinum and Agrobacterium tumefaciens homologs of BcsZ (CMCax and CelC, respectively) demonstrate their profound effect on cellulose production in vivo (11)(12)(13).…”

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confidence: 99%

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Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

Mazur

Zimmer

2011

Journal of Biological Chemistry

103

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Cellulose, a very abundant extracellular polysaccharide, is synthesized in a finely tuned process that involves the activity of glycosyl-transferases and hydrolases. The cellulose microfibril consists of bundles of linear ␤-1,4-glucan chains that are synthesized inside the cell; however, the mechanism by which these polymers traverse the cell membrane is currently unknown. In Gram-negative bacteria, the cellulose synthase complex forms a trans-envelope complex consisting of at least four subunits. Although three of these subunits account for the synthesis and translocation of the polysaccharide, the fourth subunit, BcsZ, is a periplasmic protein with endo-␤-1,4-glucanase activity. BcsZ belongs to family eight of glycosyl-hydrolases, and its activity is required for optimal synthesis and membrane translocation of cellulose. In this study we report two crystal structures of BcsZ from Escherichia coli. One structure shows the wild-type enzyme in its apo form, and the second structure is for a catalytically inactive mutant of BcsZ in complex with the substrate cellopentaose. The structures demonstrate that BcsZ adopts an (␣/␣) 6 -barrel fold and that it binds four glucan moieties of cellopentaose via highly conserved residues exclusively on the nonreducing side of its catalytic center. Thus, the BcsZ-cellopentaose structure most likely represents a posthydrolysis state in which the newly formed nonreducing end has already left the substrate binding pocket while the enzyme remains attached to the truncated polysaccharide chain. We further show that BcsZ efficiently degrades ␤-1,4-glucans in in vitro cellulase assays with carboxymethyl-cellulose as substrate.Cellulose, one of the most abundant biopolymers in nature, is produced by most vascular plants and a large number of algae, but is also found in some bacteria and even tunicates (1, 2). The cellulose microfibril consists of linear chains of glucose molecules that are linked via ␤-1,4-glycosidic bonds (␤-1,4-glucan) and are bundled together to form cable-like structures outside the cell (3, 4). A key enzyme in the biosynthesis of cellulose is the membrane-embedded cellulose synthase, which catalyzes the polymerization of UDP-activated glucose molecules (5, 6) and, presumably, also the translocation of the growing polysaccharide across the cell membrane (7). The bacterial cellulose synthase (Bcs) 2 complex is predicted to form a trans-envelope secretion system comprising at least four subunits (6). Although the BcsA, -B, and -C subunits are involved in synthesizing and translocating the ␤-1,4-glucan across the inner and the outer membrane, the fourth subunit, BcsZ, is a periplasmic protein with endo-␤-1,4-glucanase activity (8).BcsZ belongs to family 8 of glycoside hydrolases (GH-8) that adopts an (␣/␣) 6 -barrel architecture, consisting of two rings of six parallel ␣-helices with opposing orientation in both rings (9). GH-8 enzymes hydrolyze glycosidic bonds with a pair of acidic residues in a reaction that inverts the anomeric configuration at the new reducing end...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

Mazur

Zimmer

2011

Journal of Biological Chemistry

103

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“…Both the degradation and the adsorption may also affect the accessibility of the substrate to enzymatic degradation. These and other effects call for investigations of enzymatic degradation of interfacial substrates, and although there has been an increased interest in the area during recent years [3,9,10,13,[15][16][17][18][19][20][21][22][23][24][25], there is still a great challenge to employ and improve these processes in a controlled way. Ellipsometry has been shown to be a useful technique in such explorations [19,26,27].…”

Section: Introductionmentioning

confidence: 99%

Enzymatic degradation of model cellulose films

Eriksson

Malmsten

Tiberg

et al. 2005

Journal of Colloid and Interface Science

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“…Only cellulases originating from a few microorganisms and higher plants have no such domains (Herve et al 2010). According to the amino acid sequence similarity and 3D structure of adsorption module, the different types of cellulases from different sources have been classified into families (Rabinovich et al 2002a). In the latest update of the CAZY database, CBMs are grouped into 71 families, which show notable variations in substrate specificity and show miscellaneous biological functions (http://www.cazy.org/ CBM1_all.html).…”

Section: Fundamentals Of Cellulose Binding Domainsmentioning

confidence: 99%

A Mini-review on the Applications of Cellulose-Binding Domains in Lignocellulosic Material Utilizations

Yang¹,

Jin²,

Zhu³

et al. 2015

BioResources

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This manuscript provides a mini review on the fundamentals of cellulose binding domains (CBDs) or cellulose binding modules (CBMs) and their applications using lignocellulosic materials. CBDs, the non-productive part of cellulases, have miscellaneous biological functions and have been widely applied in lignocellulose hydrolysis, protein engineering, structural support, metabolism, energy storage, antibiosis, immunological recognition, targeting, attachment, etc. due to their specific affinity to various substrates of lignocelluloses. Understanding of the properties and mechanisms of CBDs is of vital significance because it provides the basis for fine manipulation of cellulose-CBM interactions and eventually improves the bioconversion performance of lignocelluloses into fuels and desired chemicals. In this short review, the fundamentals of CBD, the definition of CBM family, and the structures of different CBM families are introduced. Then recent findings in the applications of CBDs are discussed relative to the lignocelllulosic utilizations.

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Cited by 133 publications

References 44 publications

Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

Enzymatic degradation of model cellulose films

A Mini-review on the Applications of Cellulose-Binding Domains in Lignocellulosic Material Utilizations

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