  Robust systems, like the molecular networks of living cells are often
resistant to single hits such as those caused by high-specificity drugs. Here
we show that partial weakening of the Escherichia coli and Saccharomyces
cerevisiae transcriptional regulatory networks at a small number (3-5) selected
nodes can have a greater impact than the complete elimination of a single
selected node. In both cases, the targeted nodes have the greatest possible
impact; still the results suggest that in some cases broad specificity
compounds or multitarget drug therapies may be more effective than individual
high-affinity, high-specificity ones. Multiple but partial attacks mimic well a
number of in vivo scenarios and may be useful in the efficient modification of
other complex systems.
