Replacement of C44, but not of C53, by histidine in SBP-DENR* leads to the loss of Rabazi conjugation (left panel). Quantitation of the Cy5 signal (right panel). HEK293 MSR cells ectopically expressing SBP-DENR* or mutants were treated for 15 min with 10 M Rabazi or Rabazi thioether (Rabazi-O). Data are represented as mean s.d., based on n = 4 independent experiments. NS, not significant; ** P < 0.01, *** P < 0.001; P = 0.0001, 0.0001, 0.0017 and 0.1753, based on a two-tailed paired t -test.
