Average incidence of gate-keeper residues flanking APRs in different datasets^*.

*Flanking positions preceding an APR are shown as PB−1, PB−2 and PB−3, where PB−1 is nearest to the APR. Similarly, flanking positions succeeding an APR are shown as PE+1, PE+2 and PE+3, where PE+1 is nearest to the APR.