Fig 2: The BH3-like region of ApoL1 does not bind to Bcl-2 family members.a Alignment of the 25-mer peptides encompassing the BH3-like region of ApoL1 and ApoL2 and the BH3-only motif of Bid and Bim. The BH3-only motif Φ1sxxΦ2xxΦ3sDzΦ4B contains four hydrophobic residues Φ1–Φ4, small residues “s” (e.g. Gly, Asp, Ser), an acidic residue “D,” and an H-bond acceptor “B.” Highlighted are the potentially problematic Ile residue of ApoL1 and ApoL2 (purple) and the hallmark residues Leu (Φ2) and Asp (D) (both in red), which engage in binding to Bcl-2 proteins. The asterisk indicates the position of E150 of the ApoL1-E150/I228/K255 haplotype. b The BH3-like helix of ApoL1 from the NMR structure (cyan) and the Fab7D6:ApoL1-BH3 peptide structure (green) superimpose well with the Bid BH3-only helix (gold; from PDB 4QVE). Key residues including leucine (Φ2, underlined) and aspartic acid (D, underlined) are shown as sticks. c Representative results from SPR experiments showing single-cycle kinetics of the binding interactions between immobilized Bcl-xL and its ligands Bid (KD 7.1 ± 0.9 nM) and Bim (KD 3.3 ± 1.2 nM) and the lack of binding to the ApoL1-BH3 peptide, the ApoL1-NTD and ApoL1 (up to 3 µM concentration). The change of the ApoL1 residue I155 to the canonical small residue alanine (ApoL1-BH3 (I155A)) did not confer any detectable interaction (up to 3µM concentration). All experiments were done in triplicate and repeated at least three times.