This set of web pages uses the open-source Java Applet program Jmol, a proposed platform-independent replacement for Chime and Rasmol, neither of which is available in an OS X native version. You will need a relatively recent Java Virtual Machine to use it. Currently the page runs Jmol 11.4.5.
Here is the color coding scheme used in many of the scripts:
Major groove -- red|
Minor groove -- yellow
Watson-Crick H-bonding face -- blue|
major groove and WC face -- purple
major groove and WC face -- green
backbone -- white, with orange P atoms|
other atoms -- brown. Sugar protons not shown.
imino protons -- pink
The buttons below the Jmol window are generally intended to be clicked in order. There are some glitches if you show/hide waters. For more sophisticated commands, bring up a console window with a right-click/control click in the Jmol window.
The list on the right takes you to each of the other Jmol pages in the DNA/RNA tutorial.If your screen is large enough, use the "big" pages.