Crystal structure of the delta-class glutathione transferase in Musca domestica.
Biochem Biophys Res Commun
; 502(3): 345-350, 2018 07 20.
Article
em En
| MEDLINE
| ID: mdl-29803675
ABSTRACT
Among the various glutathione transferase (GST) isozymes in insects, the delta- and epsilon-class GSTs fulfill critical functions during the detoxification of insecticides. We crystalized MdGSTD1, the major delta-class GST isozyme in the housefly (Musca domestica), in complex with glutathione (GSH) and solved its structure at a resolution of 1.4â¯Å. The overall folding of MdGSTD1 resembled other known delta-class GSTs. Its substrate binding pocket was exposed to solvent and considerably more open than in the epsilon-class GST from M. domestica (MdGSTE2). However, their C-terminal structures differed the most because of the different lengths of the C-terminal regions. Although this region does not seem to directly interact with substrates, its deletion reduced the enzymatic activity by more than 70%, indicating a function in maintaining the proper conformation of the binding pocket. Binding of GSH to the GSH-binding region of MdGSTD1 results in a rigid conformation of this region. Although MdGSTD1 has a higher affinity for GSH than the epsilon class enzymes, the thiol group of the GSH molecule was not close enough to serine residue 9 to form a hydrogen-bond with this residue, which is predicted to act as the catalytic center for thiol group deprotonation in GSH.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Insetos
/
Glutationa Transferase
/
Moscas Domésticas
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article