The crystal structure of UehA in complex with ectoine-A comparison with other TRAP-T binding proteins.
J Mol Biol
; 389(1): 58-73, 2009 May 29.
Article
en En
| MEDLINE
| ID: mdl-19362561
Substrate-binding proteins or extracellular solute receptors (ESRs) are components of both ABC (ATP binding cassette) and TRAP-T (tripartite ATP-independent periplasmic transporter). The TRAP-T system UehABC from Silicibacter pomeroyi DSS-3 imports the compatible solutes ectoine and 5-hydroxyectoine as nutrients. UehA, the ESR of the UehABC operon, binds both ectoine and 5-hydroxyectoine with high affinity (K(d) values of 1.4+/-0.1 and 1.1+/-0.1 microM, respectively) and delivers them to the TRAP-T complex. The crystal structure of UehA in complex with ectoine was determined at 2.9-A resolution and revealed an overall fold common for all ESR proteins from TRAP systems determined so far. A comparison of the recently described structure of TeaA from Halomonas elongata and an ectoine-binding protein (EhuB) from an ABC transporter revealed a conserved ligand binding mode that involves both directed and cation-pi interactions. Furthermore, a comparison with other known TRAP-T ESRs revealed a helix that might act as a selectivity filter imposing restraints on the ESRs that fine-tune ligand recognition and binding and finally might determine the selection of the cognate substrate.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
/
Aminoácidos Diaminos
Idioma:
En
Revista:
J Mol Biol
Año:
2009
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Países Bajos