How to filter out the antibody light chains into kappa and lambda types on the PDB website?
The instructions are as follows.


Go to the RCSB PDB Webite.
Under the search bar, click Browse by Annotations.
Click the blue tab labeled SCOP.
Click the white arrow next to the folder titled All Beta Protiens.
Click the white arrow next to the folder titled Immunoglobulin-like beta-sandwich (...).
Click the white arrow next to the folder titled Immunoglobulins (Superfamily).


This is where it splits, based on your specific search.

For Light Chain, Constant Domain:


Click the white arrow next to the folder titled C1 set domains (antibody constant domain-like).
For Kappa Type, Click the folder (not the arrow) titled Immunoglobulin light chain kappa constant domain, CL-kappa.
For Lambda Type, Click the folder (not the arrow) titled Immunoglobulin light chain lambda constant domain, CL-lambda.


For Light Chain, Variable Domain:


Click the white arrow next to the folder titled V set domains (antibody variable domain-like).
For Kappa Type, Click the folder (not the arrow) titled Immunoglobulin light chain kappa variable domain, VL-kappa (...).
For Lambda Type, Click the folder (not the arrow) titled Immunoglobulin light chain lambda variable domain, VL-lambda (...).


This should get you to the list of proteins that you are looking for.