The Crystal Structure of the C-Terminal Domain of the Salmonella enterica PduO Protein: An Old Fold with a New Heme-Binding Mode
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https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016072614652
https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016072614652
Title: | The Crystal Structure of the C-Terminal Domain of the Salmonella enterica PduO Protein: An Old Fold with a New Heme-Binding Mode |
Authors: | Ortiz de Orué Lucana, Dario Hickey, Neal Hensel, Michael Klare, Johann P. Geremia, Silvano Tiufiakova, Tatiana Torda, Andrew E. |
Abstract: | The two-domain protein PduO, involved in 1,2-propanediol utilization in the pathogenic Gram-negative bacterium Salmonella enterica is an ATP:Cob(I)alamin adenosyltransferase, but this is a function of the N-terminal domain alone. The role of its C-terminal domain (PduOC) is, however, unknown. In this study, comparative growth assays with a set of Salmonella mutant strains showed that this domain is necessary for effective in vivo catabolism of 1,2-propanediol. It was also shown that isolated, recombinantly-expressed PduOC binds heme in vivo. The structure of PduOC co-crystallized with heme was solved (1.9 Å resolution) showing an octameric assembly with four heme moieities. The four heme groups are highly solvent-exposed and the heme iron is hexa-coordinated with bis-His ligation by histidines from different monomers. Static light scattering confirmed the octameric assembly in solution, but a mutation of the heme-coordinating histidine caused dissociation into dimers. Isothermal titration calorimetry using the PduOC apoprotein showed strong heme binding (Kd = 1.6 × 10−7 M). Biochemical experiments showed that the absence of the C-terminal domain in PduO did not affect adenosyltransferase activity in vitro. The evidence suggests that PduOC:heme plays an important role in the set of cobalamin transformations required for effective catabolism of 1,2-propanediol. Salmonella PduO is one of the rare proteins which binds the redox-active metabolites heme and cobalamin, and the heme-binding mode of the C-terminal domain differs from that in other members of this protein family. |
Citations: | Frontiers in Microbiology; 7, 2016; Lausanne : Frontiers Media |
URL: | https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016072614652 |
Subject Keywords: | Salmonella; heme binding; cobalamin; redox co-factor; protein structure; protein evolution |
Issue Date: | 26-Jul-2016 |
License name: | Namensnennung 4.0 International |
License url: | http://creativecommons.org/licenses/by/4.0/ |
Type of publication: | Einzelbeitrag in einer wissenschaftlichen Zeitschrift [article] |
Appears in Collections: | FB05 - Hochschulschriften Open-Access-Publikationsfonds |
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File | Description | Size | Format | |
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Frontiers in Mikrobiology_Ortiz_fmicb-07-01010.pdf | 5,05 MB | Adobe PDF | Frontiers in Mikrobiology_Ortiz_fmicb-07-01010.pdf View/Open |
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