Download MendeleyExploring the conformational space of the mobile flap in Sporosarcina pasteurii urease by cryo-electron microscopy.
Mazzei, L., Tria, G., Ciurli, S., Cianci, M.(2024) Int J Biol Macromol 283: 137904-137904
- PubMed: 39571870
- DOI: https://doi.org/10.1016/j.ijbiomac.2024.137904
- Primary Citation of Related Structures:
9GML, 9GNR - PubMed Abstract:
To fully understand enzymatic dynamics, it is essential to explore the complete conformational space of a biological catalyst. The catalytic mechanism of the nickel-dependent urease, the most efficient enzyme known, holds significant relevance for medical, pharmaceutical, and agro-environmental applications. A critical aspect of urease function is the conformational change of a helix-turn-helix motif that covers the active site cavity, known as the mobile flap. This motif has been observed in either an open or a closed conformation through X-ray crystallography studies and has been proposed to stabilize the coordination of a urea molecule to the essential dinuclear Ni(II) cluster in the active site, a requisite for subsequent substrate hydrolysis. This study employs cryo-electron microscopy (cryo-EM) to investigate the transient states within the conformational space of the mobile flap, devoid of the possible constraints of crystallization conditions and solid-state effects. By comparing two cryo-EM structures of Sporosarcina pasteurii urease, one in its native form and the other inhibited by N-(n-butyl) phosphoric triamide (NBPTO), we have unprecedently identified an intermediate state between the open and the catalytically efficient closed conformation of the helix-turn-helix motif, suggesting a role of its tip region in this transition between the two states.
Organizational Affiliation:
Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, I-40138 Bologna, Italy. Electronic address: luca.mazzei2@unibo.it.
