5y8a

Periplasmic heme-binding protein BhuT in complex with two hemes (holo-2 form)

spinqualitylabelsall models 5y8a, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5y8a is a 2 chain structure with sequence from Burkholderia cenocepacia J2315. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.001Å Ligands: CA, HEM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function B4EKB3_BURCJ Publication Abstract from PubMed Periplasmic heme-binding proteins (PBPs) in Gram-negative bacteria are components of the heme acquisition system. These proteins shuttle heme across the periplasmic space from outer membrane receptors to ATP-binding cassette (ABC) heme importers located in the inner-membrane. In the present study, we characterized the structures of PBPs found in the pathogen Burkholderia cenocepacia (BhuT) and in the thermophile Roseiflexus sp. RS-1 (RhuT) in the heme-free and heme-bound forms. The conserved motif, in which a well-conserved Tyr interacts with the nearby Arg coordinates on heme iron, was observed in both PBPs. The heme was recognized by its surroundings in a variety of manners including hydrophobic interactions and hydrogen bonds, which was confirmed by isothermal titration calorimetry. Furthermore, this study of 3 forms of BhuT allowed the first structural comparison and showed that the heme-binding cleft of BhuT adopts an "open" state in the heme-free and 2-heme-bound forms, and a "closed" state in the one-heme-bound form with unique conformational changes. Such a conformational change might adjust the interaction of the heme(s) with the residues in PBP and facilitate the transfer of the heme into the translocation channel of the importer. Structural basis for binding and transfer of heme in bacterial heme-acquisition systems.,Naoe Y, Nakamura N, Rahman MM, Tosha T, Nagatoishi S, Tsumoto K, Shiro Y, Sugimoto H Proteins. 2017 Sep 14. doi: 10.1002/prot.25386. PMID:28913898 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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