Evaluation of ACD/1D and 2D NMR Processors Running on a Mac

Paul Sigala, Dept. of Biochemistry, Stanford University, Graduate Student (Ph.D Candidate)

This review is to evaluate the performance of ACD/1D and 2D NMR Processors (v. 9.0) running on a Macintosh laptop computer using a simulated Windows PC environment. The computer is a Macintosh PowerPC G4 laptop equipped with a 1.5 GHz processor and 768 MB of RAM, and running OS 10.3.9. Microsoft Virtual PC for Mac version 7.0.1 and Microsoft Windows XP were installed to create a simulated Windows environment for running the ACD/Labs NMR Processors. The ACD/Labs software was evaluated using either 256 or 520 MB of RAM allocated to Virtual PC. Prior to acquiring the ACD/Labs software, I evaluated multiple 1D NMR processing programs running within native Macintosh environments and found none to have either the range of features, or ease of use of the ACD/1D and 2D NMR Processors.

My primary motivation in acquiring and using the ACD/Labs software was to have the freedom and portability to process and analyze various types of NMR experimental data, as well as manipulate and render spectra into a format for making publication-quality figures on my personal laptop computer. With the ACD/Labs software, I can now process and manipulate spectra at my desk, at home, or while traveling. Furthermore, both the 1D and 2D NMR Processors have features that go beyond the limitations in other processing software. For example, the peak-fitting function of the 1D Processor has been essential in my work to fit lineshapes for poorly shaped exchange-broadened resonances, both for deconvoluting overlapping resonances, as well as fitting and comparing peak areas. The ability to immediately edit spectra within ACD/ChemSketch for easy future import into other graphical editors (Adobe Illustrator, etc.) is of additional convenience. Both the 1D and 2D Processors appeared to function fully in the Virtual PC environment without issue. Since Virtual PC can run in 'full-screen' mode, ACD/Labs software use is seamless once Virtual PC and Windows XP are running. All software features described in the manual for each processor worked successfully. For the 1D Processor, this includes transformation and apodization of Varian *.fid files, phase and baseline correction of protein spectra acquired with binomial water suppression and extensive baseline roll, peak picking and deconvolution, and lineshape analysis to analyze peak areas. For the 2D Processor, this included transformation of protein N-H HSQC spectra, adjustment of contour intervals and thresholds, referencing, and peak picking, assignment annotation, and integration of peak volumes for export and analysis in other programs. No apparent software problems were encountered while running the 1D or 2D Processors, however one minor glitch involves the need to periodically re-enter the license keys in register.exe.

While the ACD/Labs software performed fully within the Virtual PC Windows XP environment, it did appear to run more slowly in comparison to Macintosh programs running within the native Mac OSX environment. This is particularly noticeable during lineshape analysis and is presumably a function of Virtual PC performance and not the ACD/Labs software per se. Allocating more RAM (512 rather than the default 256 MB) to Virtual PC did improve the speed of the ACD/Labs Processors. Despite the somewhat reduced speed, use of the ACD/Labs software within Virtual PC was otherwise facile. For example, Virtual PC could be run in 'windowed mode' which allows for ready dialog and file 'dragging and dropping' between the Windows and Mac environments.

In general, the ACD/Labs software has been invaluable for viewing and processing spectra away from the instrument. The 1D Processor, in particular, is the most user-friendly software of its kind encountered to date. Evaluation of many other potential 1D processing programs installed on a native Mac platform proved to be slow and difficult to use. The ACD/Labs software, while not made to run in a native Mac environment, becomes a viable and appealing option once Virtual PC is installed. The slightly slowed performance and delay in starting/storing Virtual PC is more than off-set by the ease of use and convenience of the ACD/Labs Processors. While other fully-featured and easy-to-use 2D processing software (such as Sparky) are available that can run within the Mac environment, the ACD/2D NMR Processor provides a convenient and user-friendly alternative with the advantage of interfacing easily with the 1D software.