Hemoglobin A (HbA): Structure, Sequence & Importance

The normal hemoglobin A sequence (also called Hb A0 or Hb A) consists of four polypeptide chains: two alpha chains and two beta chains. Each chain is composed of a specific sequence of amino acids.

The alpha chain of Hb A contains 141 amino acids and has the following sequence:

```

VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSHGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSDLHAHKLRVDPVNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKYR

```

The beta chain of Hb A contains 146 amino acids and has the following sequence:

```

VHLTPEEKSAVTALWGKVNVDEVGGEALGRLLVVYPWTQRFFESFGDLSTPDAVMGNPKVKAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHVDPENFRLLGNVLVCVLAHHFGKEFTPPVQAAYQKVVAGVANALAHKYH

```

These sequences represent the primary structures of the alpha and beta chains of Hb A. The complete hemoglobin molecule is formed by the assembly of these chains into a tetrameric structure.