Serines 66, 67 of Mlc2 are replaced by alanines in addition to lacking amino acids 2-46.
Mlc2E38 mutant flies expressing Mlc2Δ2-46,S66A,S67A are unable to fly or beat their wings.
Mlc2E38 mutants carrying Mlc2Δ2-46,S66A,S67A display sarcomeric structural abnormalities as revealed by X-ray diffraction and electron microscopy.