5CX7

Crystal Structure of PduOC:Heme Complex

Summary for 5CX7

• Entry DOI: 10.2210/pdb5cx7/pdb
• Descriptor: ATP:cob(I)alamin adenosyltransferase, PROTOPORPHYRIN IX CONTAINING FE, GLYCEROL, ... (7 entities in total)
• Functional Keywords: bis-his, heme binding domain, pduoc, unknown function
• Biological source: Salmonella enterica subsp. enterica serovar Livingstone
• Total number of polymer chains: 16
• Total formula weight: 254839.11

Authors

Geremia, S.,Hickey, N.,Ortiz de Orue Lucana, D. (deposition date: 2015-07-28, release date: 2016-06-29, Last modification date: 2024-01-10)

Primary citation

Ortiz de Orue Lucana, D.,Hickey, N.,Hensel, M.,Klare, J.P.,Geremia, S.,Tiufiakova, T.,Torda, A.E.
The Crystal Structure of the C-Terminal Domain of the Salmonella enterica PduO Protein: An Old Fold with a New Heme-Binding Mode.
Front Microbiol, 7:1010-1010, 2016

PubMed 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 (K d = 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.

PubMed: 27446048
DOI: 10.3389/fmicb.2016.01010

Experimental method

X-RAY DIFFRACTION (1.97 Å)