Title
Molecular characterization of myoglobin from Sciurus vulgaris meridionalis: Primary structure, kinetics and spectroscopic studies
Author
Antonella M.A. Di Giuseppe, Luigi Russo, Rosita Russo, Sara Ragucci, J. Valentina Caso, Carla Isernia, Angela Chambery, Antimo Di Maro
Year
2017
Journal
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Abstract
Myoglobins (Mbs) are heme-proteins involved in dioxygen storage necessary for metabolic respiration. Mbs are intensely investigated as archetype to investigate structure/function relationship in globular proteins. In this work, the myoglobin from S. vulgaris meridionalis has been for the first time isolated and purified with a high yield and homogeneity. The primary structure characterization has been performed by applying a strategy based on high resolution tandem mass spectrometry. Proximal (position 93, α-helix F8) and distal histidinyl residues (position 64, α-helix E7) as well as most of the amino acid residues (i.e., Leu29, Lys45, Thr67, Val68) involved in the autoxidation mechanism are conserved in the squirrel Mb. The structural and dynamical properties of the squirrel Mb have been also deeply investigated by CD, NMR. Furthermore, molecular dynamics studies of Mbs from different species have been performed. In addition, the functional properties of squirrel Mb have been characterized by determining its autoxidation kinetic and thermal stability in comparison with crested porcupine and reindeer Mbs. Interestingly, a higher autoxidation rate was revealed for squirrel Mb with respect to reindeer and crested porcupine Mbs. Even considering the very similar structural fold, molecular dynamics data show a higher conformational mobility of squirrel Mb with respect to reindeer and crested porcupine.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Thermal stability, Thermodynamics, Biochemistry