Download MendeleyOpen and Lys-His Hexacoordinated Closed Structures of a Globin with Swapped Proximal and Distal Sites.
Teh, A.H., Saito, J.A., Najimudin, N., Alam, M.(2015) Sci Rep 5: 11407-11407
- PubMed: 26094577 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/srep11407
- Primary Citation Related Structures:
3WFW, 3WFX - PubMed Abstract:
Globins are haem-binding proteins with a conserved fold made up of α-helices and can possess diverse properties. A putative globin-coupled sensor from Methylacidiphilum infernorum, HGbRL, contains an N-terminal globin domain whose open and closed structures reveal an untypical dimeric architecture. Helices E and F fuse into an elongated helix, resulting in a novel site-swapped globin fold made up of helices A-E, hence the distal site, from one subunit and helices F-H, the proximal site, from another. The open structure possesses a large cavity binding an imidazole molecule, while the closed structure forms a unique Lys-His hexacoordinated species, with the first turn of helix E unravelling to allow Lys52(E10) to bind to the haem. Ligand binding induces reorganization of loop CE, which is stabilized in the closed form, and helix E, triggering a large conformational movement in the open form. These provide a mechanical insight into how a signal may be relayed between the globin domain and the C-terminal domain of HGbRL, a Roadblock/LC7 domain. Comparison with HGbI, a closely related globin, further underlines the high degree of structural versatility that the globin fold is capable of, enabling it to perform a diversity of functions.
- Centre for Chemical Biology, Universiti Sains Malaysia, 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Penang, Malaysia.
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