The Transmembrane – Goldman-Engleman-Steitz track predicts non-polar alpha helices which may span a cell membrane, using the approach of Engleman et al., 1986. To search for non-polar helices, scales of residue polarity are applied across a protein sequence. This algorithm is much more accurate at predicting membrane bound helices than other hydropathy methods, especially if the helix contains polar residues.

To apply this track to the sequence:

In the Tracks panel, expand Transmembrane and check the box next to Goldman-Engleman-Steitz. The track will now be visible in the Analysis view

To edit track options:

Select the track in the Tracks panel. Open the Track Options section, which appears as follows:

  • Residues to Average – number of residues to be averaged when constructing each point in the plot. The default is 20, which reflects the size of a common transmembrane alpha helix. 21 residues are required to span a lipid bilayer 30Å long, as the interval between residues in an alpha helix is 1.5Å.

Click if you wish to return to the default value.

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