RT info:eu-repo/semantics/article
T1 BcsA and BcsB form the catalytically active core of bacterial cellulose synthase sufficient for in vitro cellulose synthesis
A1 Omadjela, Okako
A1 Narahari, Adishesh
A1 Strumillo, Joanna
A1 Mélida Martínez, Hugo
A1 Mazur, Olga
A1 Bulone, Vincent
A1 Zimmer, Jochen
A2 Fisiologia Vegetal
K1 Ingeniería agrícola
K1 Membrane transport
K1 Biopolymer
K1 Glycobiology
K1 In vitro reconstitution
K1 2417.19 Fisiología Vegetal
AB [EN] Cellulose is a linear extracellular polysaccharide. It is synthesizedby membrane-embedded glycosyltransferases that processivelypolymerize UDP-activated glucose. Polymer synthesis is coupled tomembrane translocation through a channel formed by the cellulosesynthase. Although eukaryotic cellulose synthases function inmacromolecular complexes containing several different enzymeisoforms, prokaryotic synthases associate with additional subunitsto bridge the periplasm and the outer membrane. In bacteria,cellulose synthesis and translocation is catalyzed by the innermembrane-associated bacterial cellulose synthase (Bcs)A and BcsBsubunits. Similar to alginate and poly-β-1,6 N-acetylglucosamine,bacterial cellulose is implicated in the formation of sessile bacterialcommunities, termed biofilms, and its synthesis is likewise stimulatedby cyclic-di-GMP. Biochemical studies of exopolysaccharidesynthesis are hampered by difficulties in purifying and reconstitutingfunctional enzymes. We demonstrate robust in vitro cellulosesynthesis reconstituted from purified BcsA and BcsB proteins fromRhodobacter sphaeroides. Although BcsA is the catalytically activesubunit, the membrane-anchored BcsB subunit is essential for catalysis.The purified BcsA-B complex produces cellulose chains ofa degree of polymerization in the range 200–300. Catalytic activitycritically depends on the presence of the allosteric activator cyclicdi-GMP, but is independent of lipid-linked reactants. Our data revealfeedback inhibition of cellulose synthase by UDP but not bythe accumulating cellulose polymer and highlight the strict substratespecificity of cellulose synthase for UDP-glucose. A truncationanalysis of BcsB localizes the region required for activity ofBcsA within its C-terminal membrane-associated domain. The reconstitutedreaction provides a foundation for the synthesis of biofilmexopolysaccharides, as well as its activation by cyclic-di-GMP.
PB National Academy of Sciences of the United States of America
SN 0027-8424
LK https://hdl.handle.net/10612/20800
UL https://hdl.handle.net/10612/20800
NO Omadjela, O., Narahari, A., Strumillo, J., Mélida, H., Mazur, O., Bulone, V., & Zimmer, J. (2013). BcsA and BcsB form the catalytically active core of bacterial cellulose synthase sufficient for in vitro cellulose synthesis. Proceedings of the National Academy of Sciences of the United States of America, 110(44), 17856-17861. https://doi.org/10.1073/PNAS.1314063110
DS BULERIA. Repositorio Institucional de la Universidad de León
RD Jul 12, 2024