In this work, the high-spin ferric form of the E7Q mutant of human neuroglobin (E7Q-NGB) is studied by X-band continuous-wave electron paramagnetic resonance (CW EPR) and hyperfine sublevel correlation (HYSCORE) spectroscopy. It is shown that the use of matched pulses in the HYSCORE experiment is essential to observe the nitrogen spectral contributions. The validity of approximating the high-spin Fe(III) system (S = 5/2) as an effective S = 1/2 system is tested and the consequences for the HYSCORE simulations are highlighted. Comparative HYSCORE experiments combined with deuterium exchange experiments for aquometmyoglobin and ferric E7Q-NGB clearly show that the heme iron of the latter protein is pentacoordinated, lacking the distal water. Furthermore, CW EPR experiments show that, at high pH, the E10K residue is coordinating to the heme iron in this globin. These observations are corroborated by resonance Raman experiments and could also be reproduced for other E7 mutants of human and mouse neuroglobin. Finally, the proton and nitrogen hyperfine and nuclear quadrupole parameters obtained for ferric E7Q-NGB are discussed in detail.

Studying high-spin ferric heme proteins using pulsed EPR spectroscopy – Analysis of the ferric form of the E7Q mutant of human neuroglobin / TRANDAFIR F; P.TER HEERDT; FITTIPALDI M.; E.VINCK; S.DEWILDE; L.MOENS; S.VAN DOORSLAER. - In: APPLIED MAGNETIC RESONANCE. - ISSN 0937-9347. - STAMPA. - 31:(2007), pp. 553-572.

Studying high-spin ferric heme proteins using pulsed EPR spectroscopy – Analysis of the ferric form of the E7Q mutant of human neuroglobin

FITTIPALDI, MARIA;
2007

Abstract

In this work, the high-spin ferric form of the E7Q mutant of human neuroglobin (E7Q-NGB) is studied by X-band continuous-wave electron paramagnetic resonance (CW EPR) and hyperfine sublevel correlation (HYSCORE) spectroscopy. It is shown that the use of matched pulses in the HYSCORE experiment is essential to observe the nitrogen spectral contributions. The validity of approximating the high-spin Fe(III) system (S = 5/2) as an effective S = 1/2 system is tested and the consequences for the HYSCORE simulations are highlighted. Comparative HYSCORE experiments combined with deuterium exchange experiments for aquometmyoglobin and ferric E7Q-NGB clearly show that the heme iron of the latter protein is pentacoordinated, lacking the distal water. Furthermore, CW EPR experiments show that, at high pH, the E10K residue is coordinating to the heme iron in this globin. These observations are corroborated by resonance Raman experiments and could also be reproduced for other E7 mutants of human and mouse neuroglobin. Finally, the proton and nitrogen hyperfine and nuclear quadrupole parameters obtained for ferric E7Q-NGB are discussed in detail.
2007
31
553
572
TRANDAFIR F; P.TER HEERDT; FITTIPALDI M.; E.VINCK; S.DEWILDE; L.MOENS; S.VAN DOORSLAER
File in questo prodotto:
File Dimensione Formato  
ApplMagnRes_2007.pdf

Accesso chiuso

Descrizione: ApplMagnRes_2007
Tipologia: Pdf editoriale (Version of record)
Licenza: Tutti i diritti riservati
Dimensione 1.45 MB
Formato Adobe PDF
1.45 MB Adobe PDF   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/468257
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 17
  • ???jsp.display-item.citation.isi??? 17
social impact