Now, the hinge region of the IgA1 heavy chain —the part that gives the antibody a bit of flexibility to bind multiple antigens without being torn apart—is made up of a string of amino acids.

IgA重链铰链区由一系列氨基酸组成，赋予抗体一定结构可塑性，使其能够与多种抗原结合而不会被“撕裂”。