Another important observation is that the combined effect of a (relatively weak) OLEF pointing towards Fe6, and a strong, long-range OLEF pointing away from Fe2 induces a nonnegligible, and consistent, OLEF along the axis connecting both sites. Both for the e and d protonated form of His195, as well as when the charges of this residue are not considered, the field strengths along this axis vary from -0.2 to well over -0.4 VÅ -1 (for the diprotonated form, the magnitude is reduced to a range between +0.1 and -0.2 VÅ -1 ).