Category: Research

from the complex-molecular-machines dept.
A collaborative team from the Howard Hughes Medical Institute (HHMI) and Memorial Sloan-Kettering Cancer Center have produced the first detailed images of a protein that performs the crucial task of detecting and repairing broken strands of DNA. The images show that the protein is constructed to cradle DNA while the DNA is repaired and rejoined with great precision. A brief report appears on the HHMI website, and a research paper appeared in the 9 August 2001 issue of Nature.

The work reveals that the protein complex forms a ring that encircles and ìcradlesî the end of the strand of DNA. The scientists speculate that protein complexes on two broken ends of a DNA strand link to one another to hold the two ends in position for joining the DNA back together. They also found that the repair protein does not bind with the DNA bases, but rather grasps the sugar backbone of the DNA strand ó meaning that the protein does not ìcareî about the sequence of the DNA that it binds. The scientists also have evidence that proteins hold the DNA in precise alignment to allow re-joining by repair enzymes.

from the tinkering-with-molecular-machines dept.
An interesting article in the New York Times ("Scientists Are Starting to Add Letters to Life's Alphabet", by A. Pollack, 24 July 2001) describes attempts by researchers to modify the machinery of living systems to product novel proteins that use amino acids other than the twenty or so standard ones used by terrestrial biology. As the article puts it:
"Scientists are taking the first steps toward creating alternative life forms — organisms that use a genetic code different from the one used by all other creatures on earth . . . Such organisms, bacteria to start with, would have novel chemical units in their DNA and synthetic building blocks in their proteins. Scientists hope that such organisms can be used to study biochemical processes in new ways and to produce new medical or electronic materials that cannot now be made by living things."

Note: Access to the NYT website is free, but may require registration.

The U.S. National Science Foundation has awarded $1.45 million to scientists at the University of Pennsylvania, establishing a new Nanotechnology Science and Engineering Center that will seek out the building blocks of next-generation nanostructures. The four-year grant will fund research on how simple biological molecules organize themselves into complex structures and the development of synthetic self-assembling molecules. Details are available in this press release from 24 July 2001.

from the simulation-and-modeling dept.
The July/August 2001 issue of Computing in Science and Engineering, a joint publication of the IEEE Computer Society and the American Institute of Physics, has a special section devoted to nanotechnology. Specifically, three articles focus on modeling and simulation of nanoscale systems.
An introduction to the special issue by Guest Editors James R. Chelikowsky at the University of Minnesota and Mark A. Ratner at the Northwestern University Institute for Nanotechnology, explaining the basic issues of nanoscience, nanotechnology, and modeling, is available as an Adobe Acrobat PDF file (about 515 KB).
The text of the articles in the issue are only available to members of the Computer Society of the IEEE, but the abstracts can be accessed without membership. The topics covered include:
– Computational Nanotechnology with Carbon Nanotubes and Fullerenes
– Multiscale Simulation of Nanosystems
– Computational Electromagnetics of Metal Nanoparticles and Their Aggregates

A team of researchers led by Maureen Condic at the University of Utah School of Medicine in Salt Lake City have found that increasing the expression of a single gene that is important during development dramatically improves the ability of adult neurons to regenerate. The finding may lead to new approaches for treating damage from stroke, spinal cord injury, and other neurological conditions.
Condic and her coworkers found that increasing the expression of genes for receptors called integrin proteins dramatically increased the amount of nerve fiber growth in the adult neurons. The increase in growth was more than ten times greater than that in any other published study of regeneration by adult neurons. The adult neurons with the extra integrin genes were able to extend nerve fibers profusely even when growth-inhibiting proteins were present in the culture. The amount of growth was indistinguishable from that of neurons from newborn animals.
The work was reported in the 1 July 2001 issue of the Journal of Neuroscience.