Group I self-splicing introns catalyze their own excision from precursor RNAs by way of a two-step transesterification reaction. The catalytic core of these ribozymes is formed by two structural domains. The 2.8-angstrom crystal structure of one of these, the P4-P6 domain of the Tetrahymena thermophila intron, is described. In the 160-nucleotide domain, a sharp bend allows stacked helices of the conserved core to pack alongside helices of an adjacent region. Two specific long-range interactions clamp the two halves of the domain together: a two-Mg2+-coordinated adenosine-rich corkscrew plugs into the minor groove of a helix, and a GAAA hairpin loop binds to a conserved 11-nucleotide internal loop. Metal- and ribose-mediated backbone contacts further stabilize the close side-by-side helical packing. The structure indicates the extent of RNA packing required for the function of large ribozymes, the spliceosome, and the ribosome.

https://science.sciencemag.org/content/sci/273/5282/1678.full.pdf

Crystal Structure of a Group I Ribozyme Domain: Principles of RNA Packing

Intramolecular long-distance electron transfer (EI) has been actively studied in recent years in order to test existing theories in a quantitative way and to provide the necessary constants for predicting ET rates from simple structural parameters. Theoretical predictions of an "inverted region," where increasing the driving force of the reaction will decrease its rate, have begun to be experimentally confirmed. A predicted nonlinear dependence of ET rates on the polarity of the solvent has also been confirmed. This work has implications for the design of efficient photochemical charge-separation devices. Other studies have been directed toward determining the distance dependence of ET reactions. Model studies on different series of compounds give similar distance dependences. When different stereochemical structures are compared, it becomes apparent that geometrical factors must be taken into account. Finally, the mechanism of coupling between donor and acceptor in weakly interacting systems has become of major importance. The theoretical and experimental evidence favors a model in which coupling is provided by the interaction with the orbitals of the intervening molecular fragments, although more experimental evidence is needed.

https://science.sciencemag.org/content/sci/240/4851/440.full.pdf

Intramolecular Long-Distance Electron Transfer in Organic Molecules

https://web.uvic.ca/~agbrolo/ACA_GFS_MF_2011.pdf

A review on the fabrication of substrates for surface enhanced Raman spectroscopy and their applications in analytical chemistry.

/pdf/the-localized-to-delocalized-transition-in-mixed-valence-2a82oxt4jv.pdf

The localized-to-delocalized transition in mixed-valence chemistry.

Mixed Valence Complexes of d5‐d6 Metal Centers

Synthese de complexes a ponts peptides tels que [(NH 3 ) 5 Os III -L-Co III (NH 3 ) 5 ](BF 4 ) 5 ou L=iso(Pro) 0−4 , iso(Phe) 2 , iso(Gly) 2 (iso=isonicotinyl). Cinetique des transferts d'electron et parametres d'activation

Electron transfer across polypeptides. 5. Rapid rates of electron transfer between osmium(II) and cobalt(III) in complexes with bridging oligoprolines and other polypeptides

Roy H. Magnuson

Papers

Electron transfer across polypeptides. 5. Rapid rates of electron transfer between osmium(II) and cobalt(III) in complexes with bridging oligoprolines and other polypeptides

Redox-catalyzed carbonylation of an iron methyl complex

Synthesis of (trifluoromethanesulfonato)pentaammineosmium(III): osmium(III) pentaammine complexes

Synthesis and properties of osmium(II) and osmium(III) ammine complexes of aromatic nitrogen heterocyclics

Oxidatively promoted alkyl-to-acyl migratory insertion reactions: a thermodynamic assessment for iron methyl complexes