Download MendeleyIn Vitro Structural and Functional Studies of a Novel Cupredoxin, FtrB, from Brucella abortus 2308.
Kerkan, A., Hart, K., Martin, D.W., Pajski, J., Aidoo, B., Garcia, B.L., Roy, S., Dasgupta, S., Hematian, S., Santisteban-Veiga, A., Schaaf, N.J., Banerjee, S.(2025) ACS Omega 10: 12653-12670
- PubMed: 40191301
- DOI: https://doi.org/10.1021/acsomega.5c00690
- Primary Citation of Related Structures:
8VUK - PubMed Abstract:
FtrABCD is a four-component iron transporter found in several Gram-negative bacteria. Previous data confirm that FtrABCD can only utilize Fe 2+ and the inner membrane permease, FtrC, from this system, like its eukaryotic homologue, Ftr1p, is predicted to utilize the free energy released during Fe 2+ oxidation for the transport. Periplasmic FtrB from this system is coancestral with known copper oxidases, and the conserved D118 and H121 are predicted to bind to Cu 2+ , forming an active enzyme. In this work, we report structural data for recombinant wild-type and D118A and H121A mutants from Brucella abortus 2308 which confirm a β-sheet-rich structure which is distinct from known cupredoxins. Calorimetric studies on the wild-type protein show μM affinities for Cu 2+ and an Fe 2+ mimic (Mn 2+ ), which facilitate the formation of the active enzyme and the enzyme-substrate complex, respectively. In contrast, the D118A mutant failed to bind Cu 2+ . Finally, the electrochemical data reported here revealed biologically accessible reduction potentials for the Cu 2+ ion in the active enzyme which also showed a pseudozero-order rate of Fe 2+ oxidation at pH 6.5 and could oxidize Fe 2+ 3.5-times faster than its rate of autoxidation. Taken together, this report provides experimental data that support structural and functional predictions of FtrB under in vitro conditions.
- Department of Chemistry, East Carolina University, Science and Technology Building, Room 409, Greenville, North Carolina 27858, United States.
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