Harpers

PROTEINS: DETERMINATION OF PRIMARY STRUCTURE / 29nuclear targeting sequences, and EF hands to bindCa 2+ ). These domains generally are detected in the primarystructure by conservation of particular aminoacids at key positions. Insights into the properties andphysiologic role of a newly discovered protein thus maybe inferred by comparing its primary structure withthat of known proteins.SUMMARY• Long amino acid polymers or polypeptides constitutethe basic structural unit of proteins, and the structureof a protein provides insight into how it fulfills itsfunctions.• The Edman reaction enabled amino acid sequenceanalysis to be automated. Mass spectrometry providesa sensitive and versatile tool for determiningprimary structure and for the identification of posttranslationalmodifications.• DNA cloning and molecular biology coupled withprotein chemistry provide a hybrid approach thatgreatly increases the speed and efficiency for determinationof primary structures of proteins.• Genomics—the analysis of the entire oligonucleotidesequence of an organism’s complete genetic material—hasprovided further enhancements.• Computer algorithms facilitate identification of theopen reading frames that encode a given protein byusing partial sequences and peptide mass profiling tosearch sequence databases.• Scientists are now trying to determine the primarysequence and functional role of every protein expressedin a living cell, known as its proteome.• A major goal is the identification of proteins whoseappearance or disappearance correlates with physiologicphenomena, aging, or specific diseases.REFERENCESDeutscher MP (editor): Guide to Protein Purification. Methods Enzymol1990;182. (Entire volume.)Geveart K, Vandekerckhove J: Protein identification methods inproteomics. Electrophoresis 2000;21:1145.Helmuth L: Genome research: map of the human genome 3.0. Science2001;293:583.Khan J et al: DNA microarray technology: the anticipated impacton the study of human disease. Biochim Biophys Acta1999;1423:M17.McLafferty FW et al: Biomolecule mass spectrometry. Science1999;284:1289.Patnaik SK, Blumenfeld OO: Use of on-line tools and databases forroutine sequence analyses. Anal Biochem 2001;289:1.Schena M et al: Quantitative monitoring of gene expression patternswith a complementary DNA microarray. Science1995;270:467.Semsarian C, Seidman CE: Molecular medicine in the 21st century.Intern Med J 2001;31:53.Temple LK et al: Essays on science and society: defining disease inthe genomics era. Science 2001;293:807.Wilkins MR et al: High-throughput mass spectrometric discoveryof protein post-translational modifications. J Mol Biol1999;289:645.