The data set has kindly been made available by
Dr. Doug Ohlendorf.
Nate Winter did a rigid body refinement of the coordinates
deposited by K.P. Wilson, B.A. Malcom and B.W.Matthews
(pdb entry 1hel) to Doug Ohlendorf's data set.

The pdb file "mutant.pdb" is a model of the lysozyme
in which four residues have been replaced with ALA.
An exercise consists in replacing each of those ALA with
the correct amino acid and fitting them into the map.

Coordinates of an other lysozyme entry (pdb entry 1hew; 
J.C.Cheetam,P.J.Artymiuk,D.C.Phillips) are
also provided for comparison during the tutorial.