Crystal structure of the outer membrane active transporter FepA from Escherichia coli.
Nat Struct Biol
; 6(1): 56-63, 1999 Jan.
Article
em En
| MEDLINE
| ID: mdl-9886293
ABSTRACT
Integral outer membrane receptors for iron chelates and vitamin B12 carry out specific ligand transport against a concentration gradient. Energy for active transport is obtained from the proton-motive force of the inner membrane through physical interaction with TonB-ExbB-ExbD, an inner membrane complex. Here we report the crystal structure of an active transport, outer membrane receptor at 2.4 A resolution. Two distinct functional domains are revealed (i) a 22-stranded beta-barrel that spans the outer membrane and contains large extracellular loops which appear to function in ligand binding; and (ii) a globular N-terminal domain that folds into the barrel pore, inhibiting access to the periplasm and contributing two additional loops for potential ligand binding. These loops could provide a signaling pathway between the processes of ligand recognition and TonB-mediated transport. The blockage of the pore suggests that the N-terminal domain must undergo a conformational rearrangement to allow ligand transport into the periplasm.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
/
Proteínas de Transporte
/
Receptores de Superfície Celular
/
Escherichia coli
Idioma:
En
Revista:
Nat Struct Biol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Estados Unidos