Structural determinants of fluoride and formate binding to hemoglobin and myoglobin: Crystallographic and 1H-NMR relaxometric study

Silvio Aime, Mauro Fasano, Silvia Paoletti, Francesca Cutruzzolà, Alessandro Desideri, Martino Bolognesi, Menico Rizzi, Paolo Ascenzi

Research output: Contribution to journalArticlepeer-review

Abstract

The x-ray crystal structure of the fluoride derivative of ferric sperm whale (Physeter catodon) myoglobin (Mb) has been determined at 2.5 Å resolution (R = 0.187) by difference Fourier techniques. The fluoride anion, sitting in the central part of the heme distal site and coordinated to the heme iron, is hydrogen bonded to the distal His(64)E7 NE2 atom and to the W195 solvent water molecule. This water molecule also significantly interacts with the same HisE7 residue, which stabilizes the coordinated fluoride ion. Moreover, fluoride and formate binding to ferric Aplysia limacina Mb, sperm whale (Physeter catodon) Mb, horse (Caballus caballus) Mb, loggerhead sea turtle (Caretta caretta) Mb, and human hemoglobin has been investigated by 1H-NMB relaxometry. A strong solvent proton relaxation enhancement is observed for the fluoride derivatives of hemoproteins containing HisE7. Conversely, only a small outer-sphere contribution to the solvent relaxation rate has been observed for all of the formate derivatives considered and for the A. limacina Mb:fluoride derivative, where HisE7 is replaced by Val.

Original languageEnglish
Pages (from-to)482-488
Number of pages7
JournalBiophysical Journal
Volume70
Issue number1
Publication statusPublished - Jan 1996

ASJC Scopus subject areas

  • Biophysics

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