Role of conserved active site tryptophan-101 in functional activity and stability of phosphoserine aminotransferase from an enteric human parasite.
Amino Acids
; 43(1): 483-91, 2012 Jul.
Article
em En
| MEDLINE
| ID: mdl-22038178
ABSTRACT
Site-directed mutagenesis study was performed to elucidate the role of conserved tryptophan-101 present at the active site of phosphoserine aminotransferase from an enteric human parasite Entamoeba histolytica. Fluorescence resonance energy transfer and molecular dynamic simulation show that the indole ring of Trp101 stacks with the cofactor PLP. Loss of enzymatic activity and PLP polarization values suggest that Trp101 plays a major role in maintaining a defined PLP microenvironment essentially required for optimal enzymatic activity. Studies on W101F, W101H and W101A mutants show that only the indole ring of the conserved Trp101 forms most favorable stacking interaction with the pyridine ring of the cofactor PLP. Protein stability was compromised on substitution of Trp101 with Phe/His/Ala amino acids. A difference in conformational free energy of 1.65 kcal mol(-1) was observed between WT-protein and W101A mutant.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Triptofano
/
Entamoeba histolytica
/
Transaminases
Limite:
Humans
Idioma:
En
Revista:
Amino Acids
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Índia