Multistep modeling of protein structure: Application to bungarotoxin

Modelling of bungarotoxin in atomic details is presented in this article. The model‐building procedure utilizes the low‐resolution crystal coordinates of the c‐alpha atoms of bungarotoxin, sequence homology within the neurotoxin family, as well as high‐resolution x‐ray diffraction data of cobratoxin and erabutoxin. Our model‐building procedure involves: (a) principles of comparative modelling, (b) embedding procedures of distance geometry, and (c) use of molecular mechanics for optimizing packing. The model is not only consistent with the c‐alpha coordinates of crystal structure, but also agrees with solution conformational features of the triple‐stranded beta sheet as observed by noe measurements [1].