Fluorescence spectra of human neuroglobin

The fluorescence quenching spectra of neuroglobin by cesium ion, iodide and acrylamide, synchronous fluorescence spectra, and 8-anilino-1-naphthalene-sulfonic acid binding property were investigated. The intrinsic fluorescence of neuroglobin cannot be effectively quenched by cesium ion, with a Stern–Volmer constant of 0.23 ± 0.01. However, it can be significantly quenched by iodide and acrylamide with Stern–Volmer constants of 1.30 ± 0.04 and 4.56 ± 0.10, respectively. The results of synchronous fluorescence spectra indicate that tryptophan residues are distributed on both the surface and interior of neuroglobin molecule, but most of them are buried in the hydrophobic interior. The neuroglobin molecule has different conformational states in various pH solutions.