RRS1 and infection: As shown in Fig. 2A exemplarily for RRR, RKR and KKK and for all mutants in Fig. 2B, the infectivity rates of all three sets of RRR- to KKK-mutants were reduced in a descending order from (i) the RRR- to the (RRK, RKR, RKK, KRR)-mutants followed by (ii) the (KRK, KKR) mutants and finally (iii) by the KKK-mutants which had the lowest infection rates.