The helical wheel is a useful device for studying alpha helices. The 'wheel' is a view along the long axis of the helix, with numbered positions and residues indicated. This Java applet accepts user-entered peptide sequences and displays the peptide in a helical wheel presentation. Enter the sequence of a peptide you wish to study (any length up to 256 residues), and click on 'Submit String' and the helical wheel view of your peptide will appear, together with a linear presentation of your helix with arrow buttons on either side.

This Java Applet is written by Edward K. O'Neil and Charles M. Grisham (University of Virginia in Charlottesville, Virginia) and accessible at Here

The linear array of boxes shows which residues of your peptide are displayed currently in the wheel. By clicking on the arrow buttons, you can 'scroll' your peptide through the wheel.

The colors of the residues in the wheel indicate the nature of each residue (nonpolar; polar uncharged; acidic; or basic). Click on the 'Clickable' button and the colors disappear. In this mode, when you click to highlight a residue in the linear array of boxes, the residue will be highlighted in yellow, both in the linear presentation and in the wheel.

Instead of studying your own peptide, you may prefer to 'Choose a Peptide' from a built-in list, by clicking on the appropriate button.