Before revision:  We analyze the available experimental data and show that for proteins where a single SCA sectoris identified, the functionally-significant residues can also be found using single-site statistics such as conservation. We thus point to the need for more data for the cases in which several sectors are predicted by SCA .
After revision:  We analyze the available experimental data and note that it involves almost exclusively proteins with a single sector. We show that in this case sequence conservation is the need for more data for the cases in which several sectors are predicted by SCA .