Single vs. multiple ligand pathways in globins

► We model the non-biased oxygen entrance in two globins: Mb and CerHb. ► The simulations show specificity to the system. ► Mb presents multiple entrance pathways. CerHb only one apolar channel. ► 64% of entrance in Mb's active site is done by the distal histidine. ► Monte Carlo methods (PELE) are capable of mapping long timescale ligand migration.