Amyloid ß chaperone - lipocalin-type prostaglandin D synthase acts as a peroxidase in the presence of heme.
Biochem J
; 477(7): 1227-1240, 2020 04 17.
Article
em En
| MEDLINE
| ID: mdl-32271881
ABSTRACT
The extracellular transporter, lipocalin-type prostaglandin D synthase (L-PGDS) binds to heme and heme metabolites with high affinity. It has been reported that L-PGDS protects neuronal cells against apoptosis induced by exposure to hydrogen peroxide. Our study demonstrates that when human WT L-PGDS is in complex with heme, it exhibits a strong peroxidase activity thus behaving as a pseudo-peroxidase. Electron paramagnetic resonance studies confirm that heme in the L-PGDS-heme complex is hexacoordinated with high-spin Fe(III). NMR titration of heme in L-PGDS points to hydrophobic interaction between heme and several residues within the ß-barrel cavity of L-PGDS. In addition to the transporter function, L-PGDS is a key amyloid ß chaperone in human cerebrospinal fluid. The presence of high levels of bilirubin and its derivatives, implicated in Alzheimer's disease, by binding to L-PGDS may reduce its chaperone activity. Nevertheless, our ThT binding assay establishes that heme and heme metabolites do not significantly alter the neuroprotective chaperone function of L-PGDS. Guided by NMR data we reconstructed the heme L-PGDS complex using extensive molecular dynamics simulations providing a platform for mechanistic interpretation of the catalytic and transporting functions and their modulation by secondary ligands like Aß peptides and heme metabolites.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos beta-Amiloides
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Peroxidase
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Chaperonas Moleculares
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Oxirredutases Intramoleculares
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Lipocalinas
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Heme
Limite:
Humans
Idioma:
En
Revista:
Biochem J
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Singapura