Hydrogen peroxide induces heme degradation and protein aggregation in human neuroglobin: roles of the disulfide bridge and hydrogen-bonding in the distal heme cavity.
FEBS J
; 290(1): 148-161, 2023 01.
Article
in En
| MEDLINE
| ID: mdl-35866372
ABSTRACT
In the present study, human neuroglobin (hNgb) was found to undergo H2 O2 -induced breakdown of the heme center at a much slower rate than other globins, namely in the timescale of hours against minutes. We investigated how the rate of the process is affected by the Cys46/Cys55 disulfide bond and the network of non-covalent interactions in the distal heme side involving Tyr44, Lys67, the His64 heme iron axial ligand and the heme propionate-7. The rate is increased by the Tyr44 to Ala and Phe mutations; however the rate is lowered by Lys67 to Ala swapping. The absence of the disulfide bridge slows down the reaction further. Therefore, the disulfide bond-controlled accessibility of the heme site and the residues at position 44 and 67 affect the activation barrier of the reaction. Wild-type and mutated species form ß-amyloid aggregates in the presence of H2 O2 producing globular structures. Furthermore, the C46A/C55A, Y44A, Y44F and Y44F/C46A/C55A variants yield potentially harmful fibrils. Finally, the nucleation and growth kinetics for the aggregation of the amyloid structures can be successfully described by the Finke-Watzky model.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Aggregates
/
Hydrogen Peroxide
Limits:
Humans
Language:
En
Journal:
FEBS J
Journal subject:
BIOQUIMICA
Year:
2023
Document type:
Article
Affiliation country:
Italia