9X2M

Gut transporter with sorbitol

Summary for 9X2M

• Entry DOI: 10.2210/pdb9x2m/pdb
• EMDB information: 66479
• Descriptor: PTS system glucitol/sorbitol-specific EIIB component, PTS system glucitol/sorbitol-specific EIIC component, sorbitol (3 entities in total)
• Functional Keywords: sugar phosphotransferase system, pts, glucitol/sorbitol, pts gut family, transport protein
• Biological source: Escherichia coli K-12; More
• Total number of polymer chains: 6
• Total formula weight: 162418.00

Authors

Deng, T.,Ge, X.,Wang, J. (deposition date: 2025-10-06, release date: 2026-03-04, Last modification date: 2026-05-06)

Primary citation

Deng, T.,Liu, X.,Zeng, J.,Ge, X.,Wang, J.
A trimeric architecture reveals the glucitol PTS transporter as a distinct superfamily.
Commun Biol, 9:-, 2026

PubMed Abstract: The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) catalyzes the transport and phosphorylation of carbohydrates. The glucitol (Gut) PTS transporter from Escherichia coli has often been discussed in relation to the Glucose-Fructose-Lactose (GFL) superfamily, although other work has suggested that it may instead form a separate PTS superfamily. This uncertainty is linked to its unusual genetic organization, in which the transmembrane IIC domain is divided into two polypeptides (IIC1/GutE and IIC2/GutA). Here, we present the cryo-electron microscopy (cryo-EM) structure of the complete Gut transporter, which resolves this discrepancy by revealing a homotrimeric architecture for its transmembrane domain-a fold unprecedented among sugar-transporting PTS permeases. This structural evidence supports the view that the Gut family represents a distinct PTS superfamily. Within the trimer, the protomers are captured in inward-facing and inward-occluded conformations, providing a structural basis for an alternating-access transport mechanism. Furthermore, the structure suggests a unique in-trans phosphotransfer pathway between the IIB and IIC domains of adjacent subunits and identifies the substrate-binding pocket at the GutA/GutE interface. Our work redefines the structural landscape of PTS transporters and provides a mechanistic framework for sugar transport by this unique trimeric porter.

PubMed: 41807737
DOI: 10.1038/s42003-026-09835-0

Experimental method

ELECTRON MICROSCOPY (3.44 Å)