In the paper "Mutation of the His ligand in mitoNEET stabilizes the 2Fe-2S cluster despite conformational heterogeneity in the ligand environment" by Conlan Andrea R (2011) published in Acta Crystit it is said "...the likely importance of the His87-Lys55 interaction in the wild-type protein..." (Introduction of the paper). What is the function of this His87-Lys55 binding in wild-type mitoNEET ? Thanks in advance for your answers.