In this study, we have investigated the role of electrostatics in the mechanism of nitrogenasecatalyzed N₂ fixation, focusing on the local electric fields generated by the protein matrix surrounding the M-cluster (i.e. FeMoco, FeVco and FeFeco). Our analysis reveals that Fe2 and Fe6, the prime candidates for N₂ coordination and activation, experience markedly different electrostatic environments. The Fe2 site is surrounded by a strong and consistent outward-pointing electric field, while the field around Fe6 tends to be weaker, and is oriented in the opposite direction. These patterns are recovered both with fixed-charge and polarizable force-fields, and they persist across all three M-cluster types, suggesting an evolutionary adaptation rather than an incidental feature.