1.2 Angstroms crystal structure of the S. pneumoniae PhtA histidine triad domain a novel zinc binding fold

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Colleges, School and Institutes


The recently described pneumococcal histidine triad protein family has been shown to be highly conserved within the pneumococcus. As part of our structural genomics effort on proteins from Streptococcus pneumoniae, we have expressed, crystallised and solved the structure of PhtA-166-220 at 1.2 Angstroms using remote SAD with zinc. The structure of PhtA-166-220 shows no similarity to any protein structure. The overall fold contains 3beta-strands and a single short alpha-helix. The structure appears to contain a novel zinc binding motif. The remaining 4 histidine triad repeats from PhtA have been modelled based on the crystal structure of the PhtA histidine triad repeat 2. From this modelling work, we speculate that only three of the five histidine triad repeats contain the residues in the correct geometry to allow the binding of a zinc ion.


Original languageEnglish
Pages (from-to)5353-60
Number of pages8
JournalFEBS Letters
Issue number24
Publication statusPublished - 10 Oct 2005


  • Amino Acid Sequence, Bacterial Proteins, Binding Sites, Crystallography, X-Ray, Histidine, Models, Molecular, Molecular Sequence Data, Protein Conformation, Streptococcus pneumoniae, Zinc