Fig. 5.

Stochastic AID-catalyzed deamination. a Diverse AID deamination patterns on individual substrates containing 30 AAC (red dot) and AGC (orange dot) hot deamination motifs. AID deamination at the target motifs is shown as T [17]. The representative clones contain 2–10 mutations, distributed as singletons or clusters (doublets, triplets, etc.). b Random walk model depicting AID scanning and catalyzing inefficient deamination of C to U on ssDNA [17]. AID binds to ssDNA randomly and slides in both direction, while catalyzing C deaminations processively. The sliding/hopping distance is determined by a geometric distribution. A good fit of the model to the data occurs when AID slides/hops for average distance of 10 motifs (30 nt), but only rarely deaminates C to U, at about 3 % efficiency for even “hottest” AAC motifs, thus ensuring mutational diversity [17]