Investigating the active site of human trimethyllysine hydroxylase.
Biochem J
; 476(7): 1109-1119, 2019 04 10.
Article
em En
| MEDLINE
| ID: mdl-30898847
ABSTRACT
The biologically important carnitine biosynthesis pathway in humans proceeds via four enzymatic steps. The first step in carnitine biosynthesis is catalyzed by trimethyllysine hydroxylase (TMLH), a non-heme Fe(II) and 2-oxoglutarate (2OG)-dependent oxygenase, which catalyzes the stereospecific hydroxylation of (2S)-Nε-trimethyllysine to (2S,3S)-3-hydroxy-Nε-trimethyllysine. Here, we report biocatalytic studies on human TMLH and its 19 variants introduced through site-directed mutagenesis. Amino acid substitutions at the sites involved in binding of the Fe(II) cofactor, 2OG cosubstrate and (2S)-Nε-trimethyllysine substrate provide a basic insight into the binding requirements that determine an efficient TMLH-catalyzed conversion of (2S)-Nε-trimethyllysine to (2S,3S)-3-hydroxy-Nε-trimethyllysine. This work demonstrates the importance of the recognition sites that contribute to the enzymatic activity of TMLH the Fe(II)-binding H242-D244-H389 residues, R391-R398 involved in 2OG binding and several residues (D231, N334 and the aromatic cage comprised of W221, Y217 and Y234) associated with binding of (2S)-Nε-trimethyllysine.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigenases de Função Mista
Limite:
Humans
Idioma:
En
Revista:
Biochem J
Ano de publicação:
2019
Tipo de documento:
Article