Eric Meggers

A guanine radical cation (G+•) was site-selectively generated in double stranded DNA and the charge transfer in different oligonucleotide sequences was investigated. The method is based on the competition between a charge transfer from G+• through the DNA and its trapping reaction with H2O. We analyzed the hole transfer from this G+• to a GGG unit through one, two, three, and four AT base pairs and found that the rate decreases by about 1 order of magnitude with each intervening AT base pair. This strong distance dependence led to a β-value of 0.7 ± 0.1 Å-1. Within the time scale of this assay the charge transfer nearly vanished when the G+• was separated by four AT base pairs from the GGG unit. However, if the second or the third of the four intervening AT base pairs was exchanged by a GC base pair, the rate of the hole transfer from the G+• to the GGG unit increased by 2 orders of magnitude. In addition, a long-range charge transfer over 15 base pairs could be observed in a mixed strand that contained AT as well as GC base pairs. Because G+• can oxidize G but not A bases, the long-range charge transport can be explained by a hopping of the positive charge between the intervening G bases. Thus, the overall charge transport in a mixed strand is a multistep hopping process between G bases where the individual steps contribute to the overall rate. The distance dependence is no longer described by the β value of the superexchange mechanism.

Unique properties of metal complexes, such as structural diversity, adjustable ligand exchange kinetics, fine-tuned redox activities, and distinct spectroscopic signatures, make them exciting scaffolds not only for binding to nucleic acids but increasingly also to proteins as non-traditional targets. This feature article discusses recent trends in this field. These include the use of chemically inert metal complexes as structural scaffolds for the design of enzyme inhibitors, new strategies for inducing selective coordination chemistry at the protein binding site, recent advances in the development of catalytic enzyme inhibitors, and the design of metal complexes that can inject electrons or holes into redox enzymes. A common theme in many of the discussed examples is that binding selectivity is at least in part achieved through weak interactions between the ligand sphere and the protein binding site. These examples hint to an exciting future in which "organic-like" molecular recognition principles are combined with properties that are unique to metals and thus promise to yield compounds with novel and unprecedented properties.

Visible light driven organic chemistry has sparked much excitement over the last several years. This review summarizes recent progress in combining visible light activation with asymmetric catalysis, processes that are either mediated by photoinduced electron or energy transfer. The tasks of photoactivation and asymmetric catalysis are typically accomplished by dual catalyst systems but several recent reports demonstrate that they can also be effectively executed by single catalysts. Beyond the discovery of novel asymmetric transformations under mild reaction conditions, this contemporary area of organic chemistry holds promise for the development of economical and environmentally friendly methods for the asymmetric synthesis of chiral compounds.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Copper-Mediated DNA Base PairEric Meggers, Patrick L. Holland, William B. Tolman, Floyd E. Romesberg, and Peter G. SchultzView Author Information Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla, California 92037 Department of Chemistry University of Minnesota 207 Pleasant Street SE, Minneapolis, MN 55455 Cite this: J. Am. Chem. Soc. 2000, 122, 43, 10714–10715Publication Date (Web):October 13, 2000Publication History Received14 July 2000Published online13 October 2000Published inissue 1 November 2000https://pubs.acs.org/doi/10.1021/ja0025806https://doi.org/10.1021/ja0025806rapid-communicationACS PublicationsCopyright © 2000 American Chemical SocietyRequest reuse permissionsArticle Views3429Altmetric-Citations326LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Genetics,Ions,Ligands,Melting,Nucleobases Get e-Alerts