Fig. 1: BcsA coordinates a BcsG trimer. | Nature Communications

Fig. 1: BcsA coordinates a BcsG trimer.

From: Insights into phosphoethanolamine cellulose synthesis and secretion across the Gram-negative cell envelope

Fig. 1

a Schematic representation of the pEtN transfer reaction catalyzed by BcsG. PE lipid Phosphatidylethanolamine, Ser Ser278 as catalytic nucleophile, pEtN Phosphoethanolamine. b Cartoon illustration of the Ec cellulose synthase complex. The putative cellulose secretion path is shown as a dashed line. c Low-resolution cryo-EM map of the Ec inner membrane-associated cellulose synthase complex (IMC, EMD-23267). d AlphaFold2-predicted structure of Ec BcsG (AF-P37659-F1) with close-up showing the acidic cavity extending from the putative membrane surface. e Cryo-EM composite map of the IMC after focused refinements of the periplasmic BcsB hexamer and the BcsG trimer associated with BcsA, respectively. BcsB subunits are colored from light gray to pink, BcsA and trimeric BcsG are colored in shades of blue and yellow respectively, and the associated BcsB transmembrane (TM) helix is colored gray. Contour level: 5σ. f AlphaFold2-predicted complex of BcsA, BcsB’s TM anchor, and the trimeric BcsG colored as in (e). g Co-purification of Ec BcsG (His-tagged) with the N-terminal domain of Ec BcsA (NTD, Strep-tagged) by immobilized metal (IMAC) and Strep-Tactin affinity chromatography followed by size exclusion chromatography (SEC). Source data are provided as a Source Data File.

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