Ligand-Mediated Folding of the OmpA Periplasmic Domain from Acinetobacter baumannii.
Biophys J
; 112(10): 2089-2098, 2017 May 23.
Article
em En
| MEDLINE
| ID: mdl-28538146
ABSTRACT
The periplasmic domain of OmpA from Acinetobacter baumannii (AbOmpA-PD) binds to diaminopimelate and anchors the outer membrane to the peptidoglycan layer in the cell wall. Although the crystal structure of AbOmpA-PD with its ligands has been reported, the mechanism of ligand-mediated folding of AbOmpA remains elusive. Here, we report that in vitro refolded apo-AbOmpA-PD in the absence of ligand exists as a mixture of two partially folded forms in solution mostly unfolded (apo-state I) and hololike (apo-state II) states. Binding of the diaminopimelate or glycine ligand induced complete folding of AbOmpA-PD. The apo-state I was highly flexible and contained some secondary structural elements, whereas the apo-state II closely resembled the holo-state in terms of both structure and backbone dynamics, except for the ligand-binding region. 15N-relaxation-dispersion analyses for apo-state II revealed substantial motion on a millisecond timescale of residues in the H3 helix near the ligand-binding site, with this motion disappearing upon ligand binding. These results provide an insight into the ligand-mediated folding mechanism of AbOmpA-PD in solution.
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Temas:
ECOS
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Financiamentos_gastos
Bases de dados:
MEDLINE
Assunto principal:
Proteínas da Membrana Bacteriana Externa
Tipo de estudo:
Health_economic_evaluation
Idioma:
En
Revista:
Biophys J
Ano de publicação:
2017
Tipo de documento:
Article