Katerina, Carolina and Javi recent publication

This work uses X-ray crystallography and extended Molecular Dynamics simulations to describe the structure and the dynamic properties of the nerve globin (nHb) from the Atlantic surf clam Spisula solidissima (SsHb). SsHb has been previously suggested to display a bis-histidyl hexa-coordinated heme in the deoxy state and shown to have high O2 affinity and ligand binding cooperativity when assayed in situ. This study confirms that SsHb displays a ‘classic’ globin fold with bis-histidyl hexa-coordination of the heme-Fe atom and identify His71(E7) and His103(F8) as the distal and proximal coordinating residues, respectively. The discovery of a dimeric SsHb in the crystal structure gave important insights into the interactions at the subunits interface, particularly regarding the relative locations of the two hemes, and the crosstalk between heme-propionates and protein residues, to explore their potential roles on the cooperative behavior reported for this globin in vivo. Further, the structural and dynamical features of SsHb, in different ligated states (bis-histidyl hexa-coordinate, deoxy pentacoordinate,O2-bound hexa-coordinated), have been examined by means of extended molecular dynamics simulations, allowing to disclose the structural features that may be implicated in the hexa-to-penta-coordination transition and association-dissociation of the dimeric SsHb.

 

In this project they collaborated with different groups in Italy, and more especially with Prof. Marco Nardini and Prof. Martino Bolognesi. Also they collaborated with Prof. Sylvia Dewilde, who sadly passed away some time ago. This article is also on her honour.