Immunoglobulin lambda variable 7-43 (Ig lambda chain V region 4A)
1_MAWTP 6_ LFLFL 11_ LTCCP 16_ GSNSQ 21_ TVVTQ 26_ EPSLT 31_ VSPGG 36_ TVTLT 41_ CASST 46_ GAVTS 51_ GYYPN 56_ WFQQK 61_ PGQAP 66_ RALIY 71_ STSNK 76_ HSWTP 81_ ARFSG 86_ SLLGG 91_ KAALT 96_ LSGVQ 101_ PEDEA 106_ EYYCL 111_LYYGG
1: V region of the variable domain of immunoglobulin light chains that participates in the antigen recognition (PubMed:24600447). Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:20176268, PubMed:22158414). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:17576170, PubMed:20176268)