6ON4

Crystal structure of the GntR-type sialoregulator NanR from Escherichia coli, in complex with sialic acid

Summary for 6ON4

• Entry DOI: 10.2210/pdb6on4/pdb
• Descriptor: HTH-type transcriptional repressor NanR, N-acetyl-beta-neuraminic acid, ZINC ION, ... (5 entities in total)
• Functional Keywords: transcriptional repressor, bacterial sialic acid catabolism, dna binding protein
• Biological source: Escherichia coli K-12
• Total number of polymer chains: 2
• Total formula weight: 60170.19

Authors

Horne, C.R.,Panjikar, S.,North, R.A.,Dobson, R.C.J. (deposition date: 2019-04-19, release date: 2020-07-08, Last modification date: 2024-03-13)

Primary citation

Kalivoda, K.A.,Steenbergen, S.M.,Vimr, E.R.
Control of the Escherichia coli sialoregulon by transcriptional repressor NanR.
J. Bacteriol., 195:4689-4701, 2013

PubMed Abstract: NanR, one of >8,500 GntR superfamily helix-turn-helix transcriptional regulators, controls expression of the genes required for catabolism of sialic acids in Escherichia coli. It is predicted to do the same in related bacteria harboring orthologs of nanR. The sialic acids are a family of over 40 naturally occurring nine-carbon keto-sugar acids found mainly in the animal lineage, which includes starfish to humans in the deuterostome lineage. Sialic acids function in development, immunity, protein localization and stability, and homeostasis. They also serve as microbial carbon and nitrogen sources and ligands for cell recognition during host colonization. The importance of microbial sialic acid metabolism for host-microbe interactions has made it a target for therapeutic development. Exploiting this target depends on understanding sialometabolic pathways in a wide range of evolutionarily distinct bacteria. Here, we show by transcriptome, genetic, and biochemical analyses that the most common sialic acid, N-acetylneuraminate, induces the nanATEK-yhcH, yjhATS (nanCMS), and yjhBC operons by directly inactivating NanR, converting the predominantly dimeric form of the repressor to an inactive monomer of approximately 30-kDa. Additionally, other results identify critical amino acid residues and nucleotides in the regulator and operator, respectively. The combined results better define how sialic acids, acting through NanR, affect the metabolic flux of an important group of host-derived metabolites. Thus, E. coli serves as a valuable model for understanding sialocatabolic pathways in bacteria.

PubMed: 23935044
DOI: 10.1128/JB.00692-13

Experimental method

X-RAY DIFFRACTION (2.1 Å)