Answer:


If we look in the PDB file 1aie.pdb (you can get it by asking MRS to look for 1aie) you see in the JRNL records:

JRNL        AUTH   P.R.MITTL,P.CHENE,M.G.GRUTTER
JRNL        TITL   CRYSTALLIZATION AND STRUCTURE SOLUTION OF P53
JRNL        TITL 2 (RESIDUES 326-356) BY MOLECULAR REPLACEMENT USING
JRNL        TITL 3 AN NMR MODEL AS TEMPLATE.
JRNL        REF    ACTA CRYSTALLOGR.,SECT.D      V.  54    86 1998

So, they only solved a small part (residues 326-356) of a much larger molecule, and maintained the numbering scheme of that larger molecule).