In-cell investigation of the conformational landscape of the GTPase UreG by SDSL-EPR

Annalisa Pierro (1, 2) , Ketty C Tamburrini (3, 4) , Hugo Leguenno (5) , Guillaume Gerbaud (2) , Emilien Etienne (2) , Bruno Guigliarelli (2) , Valérie Belle (2) , Barbara Zambelli (6) , Elisabetta Mileo (2)

1 Universität Konstanz
2 BIP - Bioénergétique et Ingénierie des Protéines
3 AFMB - Architecture et fonction des macromolécules biologiques
4 BBF - Biodiversité et Biotechnologie Fongiques
5 IMM - Institut de Microbiologie de la Méditerranée
6 UNIBO - Alma Mater Studiorum Università di Bologna = University of Bologna

UreG is a cytosolic GTPase involved in the maturation network of urease, a Ni-containing bacterial enzyme. Previous investigations in vitro showed that UreG features a flexible tertiary organization, making this protein the first enzyme discovered to be intrinsically disordered. To determine whether this heterogeneous behavior is maintained in the protein natural environment, UreG structural dynamics was investigated directly in intact bacteria by in-cell EPR. This approach, based on site-directed spin labeling coupled to electron paramagnetic resonance (SDSL-EPR) spectroscopy, enables the study of proteins in their native environment. The results show that UreG maintains heterogeneous structural landscape in-cell, existing in a conformational ensemble of two major conformers, showing either random coil-like or compact properties. These data support the physiological relevance of the intrinsically disordered nature of UreG and indicates a role of protein flexibility for this specific enzyme, possibly related to the regulation of promiscuous protein interactions for metal ion delivery.

Domaines: Biologie structurale [q-bio.BM]

Annalisa Pierro, Ketty C Tamburrini, Hugo Leguenno, Guillaume Gerbaud, Emilien Etienne, et al.. In-cell investigation of the conformational landscape of the GTPase UreG by SDSL-EPR. iScience, 2023, ⟨10.1016/j.isci.2023.107855⟩. ⟨hal-04233485⟩