LociOiling Lv 1
This week's puzzle is a good match for PDB 2B48.
The protein started life as a single chain, but a long section of residues went missing in the experimental results. PDB 2B48 is missing residues 25 to 81 mid-chain. This gap is what gives the appearance of two chains in the puzzle. PDB 2B48 is also missing residues at the end of the chain.
PDB 2B48 is a dimer, with two identical copies of the protein, both with the same missing residues. Puzzle 2684 has it as a monomer, with only one copy of the protein. Between the missing residues and the missing second copy of the protein, puzzle 2684 looks a little odd. It would make more sense if we had more pieces of the puzzle.
The protein is an apoptosis inhibitor, involved in regulating the process of programmed cell death or apoptosis.