Unraveling a Ligand-Induced Twist of a Homodimeric Enzyme by Pulsed Electron-Electron Double Resonance.
Angew Chem Int Ed Engl
; 60(43): 23419-23426, 2021 10 18.
Article
in En
| MEDLINE
| ID: mdl-34387025
ABSTRACT
Mechanistic insights into protein-ligand interactions can yield chemical tools for modulating protein function and enable their use for therapeutic purposes. For the homodimeric enzyme tRNA-guanine transglycosylase (TGT), a putative virulence target of shigellosis, ligand binding has been shown by crystallography to transform the functional dimer geometry into an incompetent twisted one. However, crystallographic observation of both end states does neither verify the ligand-induced transformation of one dimer into the other in solution nor does it shed light on the underlying transformation mechanism. We addressed these questions in an approach that combines site-directed spin labeling (SDSL) with distance measurements based on pulsed electron-electron double resonance (PELDOR or DEER) spectroscopy. We observed an equilibrium between the functional and twisted dimer that depends on the type of ligand, with a pyranose-substituted ligand being the most potent one in shifting the equilibrium toward the twisted dimer. Our experiments suggest a dissociation-association mechanism for the formation of the twisted dimer upon ligand binding.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pentosyltransferases
/
Bacterial Proteins
/
Quinazolinones
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2021
Document type:
Article
Affiliation country:
Germany
Publication country:
ALEMANHA
/
ALEMANIA
/
DE
/
DEUSTCHLAND
/
GERMANY