9I1M

Structure of AauA, a sugar-binding protein with its substrate

This is a non-PDB format compatible entry.

Summary for 9I1M

• Entry DOI: 10.2210/pdb9i1m/pdb
• Descriptor: Sugar-binding protein, TETRAETHYLENE GLYCOL, (2~{S},3~{R},4~{R})-2-(hydroxymethyl)oxolane-2,3,4-triol, ... (4 entities in total)
• Functional Keywords: sugar, transporter, e.coli, substrate-binding protein, sugar binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 36235.78

Authors

Josts, I.,Cottam, C.,Connolly, J.P.R. (deposition date: 2025-01-16, release date: 2025-07-16, Last modification date: 2026-01-28)

Primary citation

Cottam, C.,Bowran, K.,White, R.T.,Basle, A.,Josts, I.,Connolly, J.P.R.
Convergent evolution of distinct D-ribulose utilisation pathways in attaching and effacing pathogens.
Nat Commun, 16:6976-6976, 2025

PubMed Abstract: Attaching and effacing pathogens overcome colonisation resistance by competing with metabolically similar organisms for limited resources. Enterohaemorrhagic E. coli (EHEC) utilises the pathogenicity island-encoded Accessory ʟ-arabinose Uptake (Aau) transporter to effectively colonise the mouse gut, hypothesised to be achieved via an enhanced capacity to scavenge ʟ-arabinose. Aau is regulated exclusively in response to ʟ-arabinose, but it is unclear how this system specifically benefits EHEC in vivo. Here, we show that Aau displays a > 200-fold higher affinity for the monosaccharide D-ribulose, over ʟ-arabinose. EHEC cannot grow on D-ribulose as a sole carbon source and this sugar does not trigger aau transcription. However, Aau effectively transports D-ribulose into the cell only in the presence of ʟ-arabinose, where it feeds into the pentose phosphate pathway, after phosphorylation by the ʟ-ribulokinase AraB, thus providing EHEC a significant fitness advantage. EHEC has therefore evolved a mechanism of hijacking the canonical ʟ-arabinose utilisation machinery to promote D-ribulose utilisation in vivo. Furthermore, Citrobacter rodentium encodes an analogous system that exclusively transports D-ribulose and metabolises it via a dedicated D-ribulokinase. These unique mechanisms of D-ribulose utilisation suggest that convergent evolution has driven the ability of distinct pathogenic species to exploit this nutrient during invasion of the gut niche.

PubMed: 40730545
DOI: 10.1038/s41467-025-62476-5

Experimental method

X-RAY DIFFRACTION (1.35 Å)