Requirement for a membrane potential for cellulose synthesis in intact cells of Acetobacter xylinum

AUTOR(ES)

Delmer, Deborah P.

RESUMO

The marked lability in cell-free preparations of the enzyme system involved in cellulose biosynthesis in most organisms studied led us to investigate factors responsible for loss of activity on cellular disruption. Previous studies have led to the suggestion that the existence of a transmembrane electrical potential (ΔΨ) may be one factor responsible for maintaining an active system in intact cells. In this report, we show that dissipation of the ΔΨ in metabolizing cells of Acetobacter xylinum results in severe inhibition of cellulose synthesis. The effect can be reversed by restoration of the ΔΨ. Inhibition of cellulose biosynthesis by dissipation of the ΔΨ can be observed under conditions in which no substantial impairment of energy metabolism occurs—i.e., under conditions in which a transmembrane pH gradient is of sufficient magnitude to maintain an adequate overall protonmotive force across the membrane. The inhibition of cellulose biosynthesis is specifically related to changes in the ΔΨ, since the process can proceed normally in the absence of the pH gradient. These results support the suggestion that loss of the ΔΨ on cellular disruption may be one of the factors responsible for the low capacity for cellulose synthesis in isolated membrane preparations and also raise the possibility that modulation of the ΔΨ could be one means of regulating the rate of cellulose synthesis in vivo.

Documentos Relacionados

• In vitro synthesis of cellulose II from a cytoplasmic membrane fraction of Acetobacter xylinum
• SYNTHESIS OF CELLULOSE FROM PYRUVATE BY SUCCINATE-GROWN CELLS OF ACETOBACTER XYLINUM
• Alternative Environmental Roles for Cellulose Produced by Acetobacter xylinum
• Genetic organization of the cellulose synthase operon in Acetobacter xylinum.
• SYNTHESIS OF CELLULOSE BY ACETOBACTER XYLINUM VI. : Growth on Citric Acid-Cycle Intermediates