Mini-myoglobin (mini-HHMb) is a fragment of horse-heart myoglobin (HHMb) considered to be the prototype of the product encoded by the central exon of the HHMb gene. For this reason, mini-HHMb has been studied extensively showing that carbonylation and oxygenation properties of the ferrous form are similar to those of the full-length protein, while kinetics and thermodynamics of azide binding to the ferric form are significantly different from those of HHMb. To analyze the structure function relationships in mini-HHMb and the role of conformational fluctuations in ligand accessibility, the molecular model of mini-HHMb has been built and refined by molecular dynamics simulations, and analyzed in parallel with that of full length HHMb. Moreover, imidazole binding parameters of ferric mini-HHMb and HHMb have been determined. Furthermore, structural data of ferric mini-HHMb and HHMb have been correlated with the imidazole and previously determined azide binding properties. Present results indicate that, despite the extensive trimming, the heme-alpha-helices E-F substructure is essentially unaltered in mini-HHMb with respect to HHMb. However, the heme-Fe atom displays an enhanced accessibility in mini-HHMb, which may affect both ligand association and dissociation kinetics.
|Titolo:||Enhanced heme accessibility in horse heart mini-myoglobin: Insights from molecular modelling and reactivity studies|
|Data di pubblicazione:||2015|
|Citazione:||Polticelli, F., Zobnina, V., Ciaccio, C., de Sanctis, G., Ascenzi, P., & Coletta, M. (2015). Enhanced heme accessibility in horse heart mini-myoglobin: Insights from molecular modelling and reactivity studies. ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 585, 1-9.|
|Appare nelle tipologie:||1.1 Articolo in rivista|