Recent trends in protein structural studies

Since the 1980's, structural studies of proteins have changed remarkably. It is currently possible to predict the entire amino acid sequence of a protein by the rapid and highly sensitive analysis of the nucleotide sequence of genomic DNA or cDNA encoding the protein. In the near future, the entire sequence of a protein may be predicted from a partial sequence just by searching a variety of databases now being constructed for many biological species. The predicted protein sequence, however, is the backbone structure of the precursor protein without post-translational modifications. Therefore, the major objectives of recent structural studies of proteins are directed to 1) rapid and sensitive confirmation of the predicted sequence and identification of those modifications present in mature proteins by newly developed mass spectrometry, 2) determination of the 3D structures of intact and mutant proteins isolated or expressed in cultured E. coli, yeast or animal cells using X-ray crystallography or NMR analysis, and 3) rapid prediction of the 3D structures of proteins utilizing protein databases. The "PROTEOME" project was proposed in 1998 to bring together all the data on the structure and function of mature proteins under international cooperation. The present paper summarizes such recent trends in protein structural studies.