Data on crystal organization in the structure of the Fab fragment from the NIST reference antibody, RM 8671
David T. Gallagher, Ioannis L. Karageorgos, Jeffrey W. Hudgens, Connor V. Galvin
This article describes the crystal packing of the unliganded antibody fragment from the NIST reference antibody 8671, whose atomic coordinates are available as Protein Data Bank structure 5K8A . Here we give information on the crystallization and structure determination, show that the packing is unique, and describe the basis for the crystals twinned growth. Twinning is a common and often serious problem in protein structure determination by x-ray crystallography . In this case the twinning is due to a small deviation (about 0.3 nm) from 4-fold symmetry in the primary crystal-building contact. The deviation produces pseudosymmetry, generating slightly different conformations of the protein, and alternating strong and weak forms of key packing interfaces.