Based on these sensitivity results we constructed different-sized QM regions according to 4 different schemes. Firstly, we distinguish between the two aforementioned schemes (reactant and reaction) and second we distinguish between single and pairwise inclusion (single and pairs). In the single inclusion scheme, we simply add bases according to their respective sensitivity without considering the corresponding counter base. With that also non-complete base pairs can be included in a QM region. In the pairwise inclusion scheme, complete base pairs are ranked and included into the QM region based on the sum of their sensitivities. The resulting QM regions can be found in Table .