Capping more than a decade of international effort, the goals of the Human Genome Project were completed successfully this year, two years ahead of schedule. The "finished" genome sequence covered 99% of the genome and closed 99.5% of the gaps in the rough draft announced about two years earlier.
A new field called "ionomics"--the study of how genes regulate levels of single-element ions in cells--was conceived by David E. Salt of Purdue University and coworkers [Nat. Biotechnol., 21, 1215 (2003)]. Mapping ion-regulating genes could aid phytoremediation of pollutant trace elements and lead to the engineering of crop plants with enhanced nutritional value.
In a study that could promote efficiencies in paper production, Vincent L. Chiang of Michigan Technological University, Houghton, and coworkers used a gene-transfer technique to create trees that contain about half the usual amount of lignin, which must be chemically removed to make paper, and up to 30% more cellulose [Proc. Natl. Acad. Sci. USA, 100, 4939 (2003)].
An analytical technique for detecting DNA at femtomole levels without any need for prior DNA amplification was developed by M. Reza Ghadiri and coworkers at Scripps [J. Am. Chem. Soc., 125, 344 (2003)]. In the technique, complementary base pairing activates an enzyme that generates an optical signal. Potential applications include point-of-care diagnosis of diseases caused by DNA defects or infectious agents.
Research on RNA interference (RNAi)--a technique in which short RNA strands are used to shut down gene expression selectively--has been experiencing explosive growth. Among other applications, the technique provides a way to rapidly assess the consequences of gene suppression in living animals, as a New York City-based group showed this year [Nat. Struct. Biol., 10, 91 (2003)].
Researchers of an enzymological persuasion catalyzed a number of impressive advances in 2003. In a study to determine how an enzyme with only a single active site catalyzes a multistep DNA-repair process, Gregory L. Verdine and coworkers at Harvard University revealed what appeared to be the first reported example of product-assisted enzymatic catalysis: a multistep process in which the product of an enzymatic reaction is used by the same enzyme to catalyze subsequent steps [Nat. Struct. Biol., 10, 204 (2003)]. Substrate-assisted enzymatic catalysis had been observed previously, but not the corresponding product-assisted process.
Karen Allen of Boston University School of Medicine, Debra Dunaway-Mariano of the University of New Mexico, and coworkers reported having used X-ray crystallography at very low temperatures to trap a high-energy oxyphosphorane intermediate in the active site of an enzyme that catalyzes phosphoryl transfer [Science, 299, 2067 (2003)]. The work appeared to resolve the question of how the enzyme performs this physiologically important reaction. However, some believe Allen, Dunaway-Mariano, and coworkers may have trapped MgF32 instead of oxyphosphorane [Science, 301, 1184 (2003)], and the issue remains undecided.
Andreas Plückthun of the University of Zurich, G. Michael Blackburn of the University of Sheffield, England, and coworkers devised an improved way to obtain highly efficient catalytic antibodies [Nat. Biotechnol., 21, 679 (2003)]. The technique combines turnover-based chemical selection from a synthetic antibody library with directed in vitro protein evolution.
Richard R. Schrock and Dmitry V. Yandulov of Massachusetts Institute of Technology developed "the most mechanistically well-defined system that reduces N2 to NH3 under modest temperature and pressure in a catalytic fashion," according to a published comment on the work. They used a molybdenum aryltriamidoamine complex to mimic the natural process by which nitrogen-fixing enzymes produce NH3 from N2 [Science, 301, 76 (2003)].
In a nutrition-related finding this year, Tadafumi Kato's group at the RIKEN Laboratory for Molecular Dynamics of Mental Disorders, Saitama, Japan, discovered that pyrroloquinoline quinone is a new member of the family of B vitamins [Nature, 422, 832 (2003)]. The compound is required for proper functioning of an enzyme that breaks down lysine, but mammals are unable to biosynthesize it, qualifying it as a vitamin.
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