The HBS helical peptide binds to a surface spanning both Switch I and II at Ras with an affinity (KD) ~ 100 μM.301 By engineering the helical motif with hydrocarbon insertions, the helical peptide ligand binds to Ras with nanomolar affinity by fitting into SI/II-P and blocks guanine nucleotide binding.302 The hydrocarbon helical peptide demonstrates inhibitory effects in cancer cell models containing KRAS G12 or G13 mutations and Drosophila melanogaster model corresponding to G12V mutation. Here, KRAS is linked to cancer.