Better inhibitory potencies were obtained using longer constraints (i.e. 4,4′-Bis(methyl)biphenyl, Bph) between cysteines introduced at i and i+6 positions (Table , Fig. ). To better accommodate such a constraint into the peptide, we also re-explored the TACC3 sequence by truncating and elongating the TACC3522-536 peptide. We found TACC3518-532, with four additional residues at the N-terminus and four fewer at the C-terminus, to be a suitable template for additional development (Fig. ; Table ; Fig. ). This sequence had marginally improved binding potency to Aurora-A when compared to the original TACC3522-536 peptide (TACC3518-532 Kd = 7.4 µM vs TACC3522-536 Kd = 10.4 µM; Fig. ), but more importantly opened up the tactical modification of additional residues not present in the original TACC3522-536 sequence.