Fig. 1.
Somatic mutations during the maturation of 93F3. (A and B) The alignment of protein sequences of 93F3 variable domains with their germ-line precursors for (A) the heavy chain and (B) the light chain. Dashes indicate identity with the germ-line sequence. The sets of somatic mutations introduced in the heavy and light chains are labeled under the mutations. Residue numbering and CDRs are as defined by Wu and Kabat (37). (C) The crystal structure of 93F3 variable domains [rendered from Protein Data Bank (PDB) ID code 1T4K with PyMOL; www.pymol.org]. The ribbons of heavy chain and light chain are colored cyan and gray, respectively. The catalytic lysine 89 and the somatic mutations in the antigen binding site are shown as thick sticks in the middle of the figure. The sets of peripheral somatic mutations are shown as thinner lines in different colors and labeled H1–H4 and L1–L2.