Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNaV1.7.

The human voltage-gated sodium channel sub-type 1.7 (hNaV1.7) is emerging as an attractive target for the development of potent and sub-type selective novel analgesics with increased potency and fewer side effects than existing therapeutics. HwTx-IV, a spider derived peptide toxin, inhibits hNaV1.7 with high potency and is therefore of great interest as an analgesic lead. In the current study we examined whether engineering a HwTx-IV analogue with increased ability to bind to lipid membranes would improve its inhibitory potency at hNaV1.7. This hypothesis was explored by comparing HwTx-IV and two analogues [E1PyrE]HwTx-IV (mHwTx-IV) and [E1G,E4G,F6W,Y30W]HwTx-IV (gHwTx-IV) on their membrane-binding affinity and hNaV1.7 inhibitory potency using a range of biophysical techniques including computational analysis, NMR spectroscopy, surface plasmon resonance, and fluorescence spectroscopy. HwTx-IV and mHwTx-IV exhibited weak affinity for lipid membranes, whereas gHwTx-IV showed improved affinity for the model membranes studied. In addition, activity assays using SH-SY5Y neuroblastoma cells expressing hNaV1.7 showed that gHwTx-IV has increased activity at hNaV1.7 compared to HwTx-IV. Based on these results we hypothesize that an increase in the affinity of HwTx-IV for lipid membranes is accompanied by improved inhibitory potency at hNaV1.7 and that increasing the affinity of gating modifier toxins to lipid bilayers is a strategy that may be useful for improving their potency at hNaV1.7

Corrigendum to "Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNaV1.7" [Biochim. Biophys. Acta 1859(5) (2017) 835-844].

The authors would like to correct Fig. 4. The electrostatic surface potential maps of HwTx-IV and gHWTx-IV are not correctly represented in the published Fig. 4B. Please find below the correct Fig. 4. [Formula presented] Although the electrostatic maps were not correct, they did not affect the discussion of the results and the conclusions. The paragraph referring to the Figure in the manuscript is correct: “Furthermore, a global profile of the electrostatic surface potential on the surface of gHwTx-IV containing the four mutations (E1G, E4G, F6W and Y33W) is more positive than the same surface on HwTx-IV (Fig. 4B), and gHwTx-IV has a higher net charge and residual dipole moment than HwTx-IV (Table 3)”. The authors would like to apologize for any inconvenience caused

Cyclizing disulfide-rich peptides using sortase A

Sortase A (SrtA) is an enzyme obtained from Staphylococcus aureus that catalyzes site-specific transpeptidation of surface proteins to the bacterial cell membrane. SrtA recognizes an LPXTG amino acid motif and cleaves between the Thr and Gly to form a thioester-linked acyl–enzyme intermediate. The intermediate is resolved in the presence of a nucleophilic N-terminal polyglycine resulting in ligation of the acyl donor to the polyglycine acceptor. Here we describe the application of SrtA as a tool for the cyclization of disulfide-rich peptides. Reactions are typically tailored to each disulfide-rich peptide with optimal conditions producing yields of 40–50% cyclized peptide