Treponema pallidum TroA is a periplasmic zinc-binding protein with a helical backbone. |
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Authors: | Y H Lee R K Deka M V Norgard J D Radolf C A Hasemann |
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Institution: | Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-8884, USA. |
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Abstract: | The crystal structure of recombinant TroA, a zinc-binding protein component of an ATP-binding cassette transport system in Treponema pallidum, was determined at a resolution of 1.8 A. The organization of the protein is largely similar to other periplasmic ligand-binding proteins (PLBP), in that two independent globular domains interact with each other to create a zinc-binding cleft between them. The structure has one bound zinc pentavalently coordinated to residues from both domains. Unlike previous PLBP structures that have an interdomain hinge composed of beta-strands, the N- and C-domains of TroA are linked by a single long backbone helix. This unique backbone helical conformation was possibly adopted to limit the hinge motion associated with ligand exchange. |
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