The electronic coupling for hole transfer between guanine bases G in the DNA duplex (GT)(6)GTG(TG)(6) is studied using a QM/MD approach. The coupling V is calculated for 10 thousand snapshots within the two- and multistate state Generalized Mulliken-Hush model. We find that the two-state scheme considerably underestimates the rate of the hole transfer within the pi stack. Moreover, the probability distributions computed with the two- and multistate schemes are quite different. It has been found that large fluctuations of V-2, which are at least an order of magnitude larger than its average value, occur roughly every 1 ps. (C) 2007 Elsevier B.V. All rights reserved.