For example, some α chains have an additional structural element (or "domain") inserted toward the N-terminal, the alpha-A domain (so called because it has a similar structure to the A-domains found in the protein von Willebrand factor; it is also termed the α-I domain).
Por exemplo, un subconxunto das cadeas α ten un elemento estrutural adicional (ou "dominio") inserido cara ao extremo N-terminal, chamado dominio alfa-A (así chamado porque ten unha estrutura similar aos dominios A que se encontran na proteína factor de von Willebrand; tamén se chama dominio α-I).