Month: August 2000

from the poke-it-again-Sam dept.
Researchers have written 0.8 nm (presumably diameter) conductive marks in a thin organic film with an STM. The marks were stable for at least the 2 hour scanning session. They attribute the marks to polymerisation of the film under the STM tip.

from the Pocket-Change dept.

Researchers have obtained the most detailed images yet of catalytic site of the ribosome, the factory where amino acids are linked into chainlike proteins.

In two articles published in the 11 August 2000 issue of Science, researchers led by Thomas A. Steitz, a Howard Hughes Medical Institute investigator at Yale University, report that they have obtained the atomic structure of the 50S subunit of the ribosome at a resolution of 2.4 Ångströms.

A press release describes the studies of the basic structure of the ribosome, which includes the first unequivocal proof that the ribosome is a ribozyme, an RNA enzyme.

from the Cutting-the-gordian-knot dept.

Custom-engineered proteins have long been seen as one possible route to molecular nanotechnology. But the challenge of understanding how and why protein molecules assume the shapes they do to perform their structural and functional roles, has been an enduring problem in the field of protein engineering.

A press release describes work that apparently explains at least some aspects of protein structure by working from first principles. "We have discovered a simple explanation, based solely on principles of geometry, for the protein's preference for the helix as a major component of its overall structure," says Jayanth R. Banavar, professor of physics at Penn State and a member of the team of U.S. and Italian research physicists that made the discovery. The work was also reported in the 20 July 2000 issue of the journal Nature.

from the Do-not-go-gently dept.

Preventing damage by ice crystals is one of the major challenges to successful cryopreservation of humans and other organisms. But it's known that some relatively large animals do survive freezing.

A press release describes work by researchers from Queen's University and the University of Alberta who have "gleaned the precise structure of winter protection proteins derived from insects." The antifreeze proteins were found to be up to 100 times more powerful than similar proteins found in fish.

from the Reverse-engineering-3billion-years-of-R&D dept.

The translation of DNA/RNA instructions and the synthesis of proteins is arguably the most complex single-site operation carried out by biological systems at the molecular level, and it's done by relatively huge molecular machines called ribosomes. Insight into the operation of these naturally evolved molecular assembly devices could be invaluable to the design of artificial molecular machines.

Researchers at the Howard Hughes Medical Institute reported in the 20 July 2000 issue of the journal Nature that they have have "detected a ratcheting rotation deep inside the cell's tiny protein-making 'factory' at a key point in the protein construction process." An overview of their work, as well as some animations of ribosome operation, appear on the HHMI web site.

from the If-it's-not-one-thing-it's-another dept.

Researchers examining complex systems, both biological and artificial, find interesting parallels between communities of organisms and the Internet in their tolerance for error — and in their high vulnerability to attack. Complex networks of nanotech devices may exhibit similar behaviors; this presents a design challenge for future MNT systems engineers, as well as today's information system engineers. The article appeared in Nature (sorry, no link, since access requires an active subscription).

If you have access to the printed journal, see "Error and attack tolerance of complex networks," by Reka Albert, Hawoong Jeong and Albert-Loszlo Barabosi, Nature, v406, pp 378 – 382.

(The full text of the abstract appears in the "Read More.")

Update: The full text of the Nature article, plus a commentary is available either online or as an Acrobat PDF file on the Nature web site. (Note: Full access may eventually be cut off, but this was current as of 31 August 2000.)

from the nano-vroom-vroom? dept.
Correction from EricDrexler: these are more accurately called actuators, not motors.
From the revised press release : "Scientists from Bell Labs, the research and development arm of Lucent Technologies, and the University of Oxford have created the first DNA motors. The devices, which resemble motorized tweezers, are 100,000 times smaller than the head of a pin, and the techniques used to make them may lead to computers that are 1,000 times more powerful than today's machines…The researchers designed pieces of synthetic DNA that would recognize each other during each step of making the DNA motors. As a result, the only necessary ingredients in a laboratory test tube were DNA itself. “Because DNA acts as the 'fuel' for these motors, they are completely self-sufficient and do not require other chemicals to operate, '' [Bell Labs physicist Bernard] Yurke said. The self-assembling aspect of the DNA motors also is crucial for manufacturing nanodevices." See the photo.