... in contributing to the coordina-tion of ganglioside binding by HCR ⁄ C and HCR ⁄ D-SA. Thus, HCR ⁄ C and HCR ⁄ D-SA utilize the GBLfor ganglioside binding. The GBLs of BoNT ⁄ C, BoNT ⁄ D and ... of HCR ⁄ C and HCR ⁄ D, but lacking a Trp. Ganglioside binding by HCR⁄ C and HCR⁄ D-SA Early studies showed that HCR ⁄ C bound GD1b and GT1b [46]. Quantitative binding assays showed thatHCR ... BoNT ⁄ D-SA, BoNT ⁄ D-South Africa; GBL, ganglioside- binding loop; GBP, ganglioside- binding pocket; HC, heavychain; HCR, heavy chain receptor -binding domain; HCT, heavy chain translocation domain...