ALAS2 and X-linked erythropoietic protoporphyria: Since ALAS2 mutations with the modified C-tail cause XLPP associated with the “gain-of-function” and consequent overproduction of protoporphyrin IX and increase in Zn2+–protoporphyrin levels, we hypothesized that the dynamics of C-tail could affect β-strand formations at the active site loop.