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-Structure paper
タイトル | Insights into phosphoethanolamine cellulose synthesis and secretion across the Gram-negative cell envelope. |
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ジャーナル・号・ページ | Nat Commun, Vol. 15, Issue 1, Page 7798, Year 2024 |
掲載日 | 2024年9月6日 |
![]() | Preeti Verma / Ruoya Ho / Schuyler A Chambers / Lynette Cegelski / Jochen Zimmer / ![]() |
PubMed 要旨 | Phosphoethanolamine (pEtN) cellulose is a naturally occurring modified cellulose produced by several Enterobacteriaceae. The minimal components of the E. coli cellulose synthase complex include the ...Phosphoethanolamine (pEtN) cellulose is a naturally occurring modified cellulose produced by several Enterobacteriaceae. The minimal components of the E. coli cellulose synthase complex include the catalytically active BcsA enzyme, a hexameric semicircle of the periplasmic BcsB protein, and the outer membrane (OM)-integrated BcsC subunit containing periplasmic tetratricopeptide repeats (TPR). Additional subunits include BcsG, a membrane-anchored periplasmic pEtN transferase associated with BcsA, and BcsZ, a periplasmic cellulase of unknown biological function. While cellulose synthesis and translocation by BcsA are well described, little is known about its pEtN modification and translocation across the cell envelope. We show that the N-terminal cytosolic domain of BcsA positions three BcsG copies near the nascent cellulose polymer. Further, the semicircle's terminal BcsB subunit tethers the N-terminus of a single BcsC protein in a trans-envelope secretion system. BcsC's TPR motifs bind a putative cello-oligosaccharide near the entrance to its OM pore. Additionally, we show that only the hydrolytic activity of BcsZ but not the subunit itself is necessary for cellulose secretion, suggesting a secretion mechanism based on enzymatic removal of translocation incompetent cellulose. Lastly, protein engineering introduces cellulose pEtN modification in orthogonal cellulose biosynthetic systems. These findings advance our understanding of pEtN cellulose modification and secretion. |
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手法 | EM (単粒子) |
解像度 | 2.65 - 5.71 Å |
構造データ | EMDB-44334, PDB-9b87: EMDB-44336, PDB-9b8a: EMDB-44345, PDB-9b8h: EMDB-44346, PDB-9b8i: EMDB-44359: Cryo-EM map of the E. coli cellulose synthase BcsAG3B6 complex ![]() EMDB-44793: E. coli cellulose synthase BcsAG3B6 complex - Consensus map ![]() EMDB-44794: E. coli cellulose synthase BcsAG3B6 complex - BcsB focused map ![]() EMDB-44795: E.coli cellulose synthase BcsAG3B6 complex - BcsAG focused map |
由来 |
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![]() | HYDROLASE / Cellulase / Endoglucanase / GH-8 family / Carbohydrate-active enzyme / MEMBRANE PROTEIN / Porin / bacterial outer membrane protein / Tetra-tricopeptide (TPR) repeats / Cellulose exporter BcsC / BcsC outer membrane protein / cellooligosaccharide / STRUCTURAL PROTEIN / bacterial cellulose synthesis / cellulose export / outer membrane porin / periplasmic protein / TRANSFERASE / phosphoethanolamine (pEtN) / catalytic BcsA-B / c-di-GMP binding protein / membrane proteins |