Monthly Archives: January 2011

Nanorings Synthesized Simply

Templating: Small templates and building blocks combine to make extra-large structures
A circular templating approach yields 4.7-nm-diameter macrocycles from small, easily prepared templates, reports a group of British researchers (Nature, DOI: 10.1038/nature09683).

The method is based on Vernier complexes, which are precise assemblies generated by the coming together of components with different numbers of binding sites—for example, different four- and six-membered building blocks. Past experiments with Vernier systems, however, have all involved linear complexes. In the new work, a group led by Harry L. Anderson, a chemistry professor at Oxford University, experimented with radial templates and linear building blocks to produce 12-membered porphyrin nanorings.

Realizing that Vernier complexes can be circular “is a significant step forward in the science of template-directed synthesis,” says J. Fraser Stoddart, a chemistry professor at Northwestern University. The technique should enable and ease the preparation of macromolecules with consistent size and shape, he adds.

Anderson and coworkers used a circular hexapyridyl template with six binding sites. They combined the template with four-membered zinc porphyrin chains, with the porphyrins linked by butadiyne groups. Three porphyrin tetramers can bind around and occupy all of the binding sites on two of the templates, linking the two in the process. The researchers then oxidatively coupled the template-bound porphyrin tetramers to form a figure-eight compound. Dissociating the porphyrins from the templates produced a 12-membered, π-conjugated porphyrin nanoring, among the largest of similar macrocycles ever synthesized. … rest

Synthetic Proteins

NEW YORK (GenomeWeb News) – In a paper appearing online this week in PLoS ONE, Princeton University researchers reported that they have successfully created synthetic proteins that can function in Escherichia coli.

Using a so-called binary code method that relies on strategic placement of polar and non-polar residues, the team made more than a million stably folded strings of amino acids from genetic sequences distinct from those known to occur naturally. They then screened these synthetic proteins in dozens of E. coli strains missing essential genes, identifying artificial proteins that could substitute for the bug’s own proteins.  … rest

Peeking at the molecular secrets of disease

Suzanne E. Winter – A new technology improves histological identification precision and could radically influence the disease diagnosis process.

Researchers at the University of Illinois at Urbana-Champaign (UIUC) have developed an imaging technology that identifies abnormal cells and normal cells on the molecular level. In a recent issue of Cancer Research, the team reports that their new diagnostic tool assesses molecule abundance and applies a color code to differentiate between healthy and diseased areas of tissue faster and more precisely than current, observation-based techniques.

Standard histological techniques section and stain a sample before it is observed by a trained specialist; these protocols tend to rely on the presence of structural changes within cell or tissue morphology to diagnose disease, such as cancers. These procedures, however, are limited by the experience and visual acuity of the technician. Furthermore, disease may be present for a considerable amount of time before structural changes can be visualized.  … rest