Number of structures available in the PDB per year through May 14, 2014, with selected examples. Early structures included myoglobin (1; PDB ID 1mbn), the first structure solved by X-ray crystallography, and small enzymes (2; top: 4pti, bottom right: 2cha, bottom left: 3cpa). As technologies developed, the archive grew to host examples of tRNA (3; 6tna), viruses (4; 4rhv), antibodies (5; 1igt), protein-DNA complexes (6; top to bottom, 1j59, 1tro, 2bop, 1aoi), ribosomes (7; 1fjg, 1fka, 1ffk), and chaperones (8; 1aon).
Myoglobin (PDB ID 1mbn): J. C. Kendrew, G. Bodo, H. M. Dintzis, R. G. Parrish, H. Wyckoff, D. C. Phillips. (1958) A three-dimensional model of the myoglobin molecule obtained by x-ray analysis. Nature 181: 662-666; J. C. Kendrew, R. E. Dickerson, B. E. Strandberg, R. G. Hart, D. R. Davies, D. C. Phillips, V. C. Shore. (1960) Structure of myoglobin: A three-dimensional Fourier synthesis at 2 A. resolution. Nature 185: 422-427; Enzymes (top, 4pti): M. Marquart, Walter, J., Deisenhofer, J., Bode, W., Huber, R. (1983) The geometry of the reactive site and of the peptide groups in trypsin, trypsinogen and its complexes with inhibitors. Acta Crystallogr B39: 480; (bottom left: 3cpa): D. W. Christianson, W. N. Lipscomb. (1986) X-ray crystallographic investigation of substrate binding to carboxypeptidase A at subzero temperature. Proc Natl Acad Sci U S A 83: 7568-7572; (bottom right: 2cha):J. J. Birktoft, D. M. Blow. (1972) Structure of crystalline alpha-chymotrypsin. V. The atomic structure of tosyl-alpha-chymotrypsin at 2 Å resolution. J Mol Biol 68: 187-240; tRNA (6tna): J. L. Sussman, S. R. Holbrook, R. W. Warrant, G. M. Church, S.-H. Kim. (1978) Crystal structure of yeast phenylalanine transfer RNA. I. Crystallographic refinement. J. Mol. Biol. 123: 607-630; Virus (4rhv): E. Arnold, M. G. Rossmann. (1988) The use of molecular-replacement phases for the refinement of the human rhinovirus 14 structure. Acta Crystallogr A 44 (Pt 3): 270-282; Antibody (1igt): L. J. Harris, S. B. Larson, K. W. Hasel, A. McPherson. (1997) Refined structure of an intact IgG2a monoclonal antibody. Biochemistry 36: 1581-1597; Protein-DNA