Immunoglobulin kappa variable 4-1 (Ig kappa chain V-IV region B17) (Ig kappa chain V-IV region JI) (Ig kappa chain V-IV region Len) (Ig kappa chain V-IV region STH)
1_MVLQT 6_ QVFIS 11_ LLLWI 16_ SGAYG 21_ DIVMT 26_ QSPDS 31_ LAVSL 36_ GERAT 41_ INCKS 46_ SQSVL 51_ YSSNN 56_ KNYLA 61_ WYQQK 66_ PGQPP 71_ KLLIY 76_ WASTR 81_ ESGVP 86_ DRFSG 91_ SGSGT 96_ DFTLT 101_ ISSLQ 106_ AEDVA 111_ VYYCQ 116_QYYST
1: V segment of the variable domain of immunoglobulins light chain 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)