PDBsum entry 2uvk

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protein Protein-protein interface(s) links
Unknown function PDB id
Protein chains
342 a.a. *
Waters ×729
* Residue conservation analysis
PDB id:
Name: Unknown function
Title: Structure of yjht
Structure: Yjht. Chain: a, b. Engineered: yes
Source: Escherichia coli. Organism_taxid: 511693. Strain: k12. Expressed in: escherichia coli. Expression_system_taxid: 511693.
1.50Å     R-factor:   0.182     R-free:   0.219
Authors: A.Muller,E.Severi,K.S.Wilson,G.H.Thomas
Key ref:
E.Severi et al. (2008). Sialic acid mutarotation is catalyzed by the Escherichia coli beta-propeller protein YjhT. J Biol Chem, 283, 4841-4849. PubMed id: 18063573 DOI: 10.1074/jbc.M707822200
12-Mar-07     Release date:   04-Dec-07    
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Protein chains
Pfam   ArchSchema ?
P39371  (NANM_ECOLI) -  N-acetylneuraminate epimerase
368 a.a.
342 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     periplasmic space   2 terms 
  Biological process     carbohydrate metabolic process   1 term 
  Biochemical function     isomerase activity     2 terms  


DOI no: 10.1074/jbc.M707822200 J Biol Chem 283:4841-4849 (2008)
PubMed id: 18063573  
Sialic acid mutarotation is catalyzed by the Escherichia coli beta-propeller protein YjhT.
E.Severi, A.Müller, J.R.Potts, A.Leech, D.Williamson, K.S.Wilson, G.H.Thomas.
The acquisition of host-derived sialic acid is an important virulence factor for some bacterial pathogens, but in vivo this sugar acid is sequestered in sialoconjugates as the alpha-anomer. In solution, however, sialic acid is present mainly as the beta-anomer, formed by a slow spontaneous mutarotation. We studied the Escherichia coli protein YjhT as a member of a family of uncharacterized proteins present in many sialic acid-utilizing pathogens. This protein is able to accelerate the equilibration of the alpha- and beta-anomers of the sialic acid N-acetylneuraminic acid, thus describing a novel sialic acid mutarotase activity. The structure of this periplasmic protein, solved to 1.5A resolution, reveals a dimeric 6-bladed unclosed beta-propeller, the first of a bacterial Kelch domain protein. Mutagenesis of conserved residues in YjhT demonstrated an important role for Glu-209 and Arg-215 in mutarotase activity. We also present data suggesting that the ability to utilize alpha-N-acetylneuraminic acid released from complex sialoconjugates in vivo provides a physiological advantage to bacteria containing YjhT.
  Selected figure(s)  
Figure 7.
Structure of YjhT. A, dimeric structure showing the arrangement of the two Kelch domains in the dimer and the dimerization interface. Each blade is colored differently, and the blade order used throughout is highlighted in blade I. B, schematic of the topology of YjhT with conserved residues Glu-209 and Arg-215 highlighted. The color scheme is the same as for A.
Figure 8.
Stereo image of YjhT highlighting the amino acid side chains of conserved residues mutagenized in this study.
  The above figures are reprinted by permission from the ASBMB: J Biol Chem (2008, 283, 4841-4849) copyright 2008.  
  Figures were selected by an automated process.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
20100283 E.Severi, A.H.Hosie, J.A.Hawkhead, and G.H.Thomas (2010).
Characterization of a novel sialic acid transporter of the sodium solute symporter (SSS) family and in vivo comparison with known bacterial sialic acid transporters.
  FEMS Microbiol Lett, 304, 47-54.  
20158882 G.A.Jenkins, M.Figueira, G.A.Kumar, W.A.Sweetman, K.Makepeace, S.I.Pelton, R.Moxon, and D.W.Hood (2010).
Sialic acid mediated transcriptional modulation of a highly conserved sialometabolism gene cluster in Haemophilus influenzae and its effect on virulence.
  BMC Microbiol, 10, 48.  
20843349 J.W.Johnston, H.Shamsulddin, A.F.Miller, and M.A.Apicella (2010).
Sialic acid transport and catabolism are cooperatively regulated by SiaR and CRP in nontypeable Haemophilus influenzae.
  BMC Microbiol, 10, 240.  
19332802 E.R.Moxon (2009).
Bacterial variation, virulence and vaccines.
  Microbiology, 155, 997.  
19564383 S.Almagro-Moreno, and E.F.Boyd (2009).
Sialic acid catabolism confers a competitive advantage to pathogenic vibrio cholerae in the mouse intestine.
  Infect Immun, 77, 3807-3816.  
19749043 S.M.Steenbergen, J.L.Jirik, and E.R.Vimr (2009).
YjhS (NanS) is required for Escherichia coli to grow on 9-O-acetylated N-acetylneuraminic acid.
  J Bacteriol, 191, 7134-7139.  
19411257 T.J.Morley, L.M.Willis, C.Whitfield, W.W.Wakarchuk, and S.G.Withers (2009).
A new sialidase mechanism: bacteriophage K1F endo-sialidase is an inverting glycosidase.
  J Biol Chem, 284, 17404-17410.  
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.