A NanoEngineer-1 Note (DNA Conversion Site, Recent Article, Related Links)

Above: A six-stranded triple-crossover (TX) DNA Junction. See Ned Seeman's ACS interview for more background.

Having just mentioned it in the context of making publication-quality pretty pictures, another brief note thanks to a citation request on the NanoEngineer Development/User Group (groups.google.com/group/nanoengineer-dev).

There's a website hosted at bionano.physics.illinois.edu for the conversion of NE-1 DNA mmp files to all-atom pdb ("Molecular Dynamics Simulation of Custom DNA Nanostructures Created by NanoEngineer-1") and NE-1's FNANO08 proceedings article ("NanoEngineer-1 – A CAD-based molecular modeling program for structural DNA nanotechnology") was included (with thanks to its use by German Barcenas) in the recent International Journal Of Molecular Sciences article "Molecular Dynamic Studies of Dye–Dye and Dye–DNA Interactions Governing Excitonic Coupling in Squaraine Aggregates Templated by DNA Holliday Junctions."

The bionano site is a dramatic improvement from the NAMOT + sed'ing I worked up many years ago while getting something DNA-related stood up.

As a still-not-irregular user myself, I can appreciate the small hurdles needed to keep the program upright in modern OSs (or the need to just run VirtualBox and be done with it) – therefore noting both Bryan Bishop's dev page (worth the visit to github for the preserved gallery alone!) and Bruce Allen's Molecular Dynamics Studio effort and sourceforge-available download.

Evaluating The Friction Of Rotary Joints In Molecular Machines

Howard Lovy's name came across my calendar (happy birthday!) and Josh Hall published a fresh post to "Where is my Flying Car?" – seems like a perfect time to post an everything-new-is-still-new-for-the-first-time-type update.

Published way back in 2017 in Molecular Systems Design & Engineering; reportedly one of the most-read Q3 2017 articles to boot. Also my first foray into arxiv territory for those limited in their journal access (arxiv.org/abs/1701.08202).

Tad Hogg*a Matthew S. Moses*b and Damian G. Allis*c

a. Institute for Molecular Manufacturing, Palo Alto, USA
b. Independent Consultant, Lafayette, USA
c. Department of Chemistry, Syracuse University, Syracuse, USA

Abstract: A computationally-efficient method for evaluating friction in molecular rotary bearings is presented. This method estimates drag from fluctuations in molecular dynamics simulations via the fluctuation–dissipation theorem. This is effective even for simulation times short compared to a bearing's energy damping time and for rotation speeds comparable to or below typical thermal values. We apply this method to two molecular rotary bearings of similar size at 300 K: previously studied nested (9,9)/(14,14) double-walled carbon nanotubes and a hypothetical rotary joint consisting of single acetylenic bonds in a rigid diamondoid housing. The acetylenic joint has a rotational frictional drag coefficient of 2 × 10^-35 kg m2 s^-1. The friction for the nested nanotubes is 120 times larger, comparable to values reported by previous studies. This fluctuation-based method could evaluate dissipation in a variety of molecular systems with similarly rigid and symmetric bearings.

Mol. Syst. Des. Eng., 2017, 2, 235-252 (10.1039/C7ME00021A, direct link)