Final answer:
The VJ junction of an immunoglobulin's light chains corresponds to the third hypervariable region, which is integral for the diverse and specific antigen-binding ability of antibodies.
Step-by-step explanation:
The VJ junction corresponds to the third hypervariable region of light chain V region. The hypervariable regions of an immunoglobulin's light chains are also known as complementarity determining regions (CDRs) because they form a surface complementary to the three-dimensional surface of a bound antigen. In germ-line B cells, genetic rearrangement involving DNA recombinase randomly excises and splices V (variable) and J (joining) segments, which results in the formation of a VJ junction contributing to the immense diversity of antibodies, allowing for millions of unique antigen-binding sites. Each differentiated B cell typically has a unique variable chain after such recombination processes.