pepinfo plots various amino acid properties in parallel for an input protein sequence. The types of plot available are i. Hydrophobicity plots using the method of Kyte & Doolittle, the optimal matching hydrophobicity scale (OHM) of Sweet & Eisenberg, or consensus parameters (Eisenberg et al). ii. Histogram of the presence of residues with the physico-chemical properties: Tiny, Small, Aliphatic, Aromatic, Non-polar, Polar, Charged, Positive, Negative. The data are also written out to an output file.
|
|
The output file 'pepinfo.out' contains the coordinates from the graphs.
For the first set of graphs, 9 sets of true/false values are written out. For the second set of graphs, 3 sets of hydrophobicity values are written.
The hydropathy data of the residues are read from the EMBOSS data file 'Eaa_hydropathy.dat'. This file can be copied into your current directory and inspected ot altered by using the application 'embossdata -fetch'. Another file can be specified using the qualifier '-aahydropathy'.
EMBOSS data files are distributed with the application and stored in the standard EMBOSS data directory, which is defined by EMBOSS environment variable EMBOSS_DATA.
Users can provide their own data files in their own directories. Project specific files can be put in the current directory, or for tidier directory listings in a subdirectory called ".embossdata". Files for all EMBOSS runs can be put in the user's home directory, or again in a subdirectory called ".embossdata".
The directories are searched in the following order:
For calculating the hydrophobicity plots, hdrophobicity is calculated in windows of a specified size over the sequence.
The optimal matching hydrophobicity scale (OHM) scale is based on the likelihood of a given amino acid to be replaced by another hydrophobic or "buried" amino acid.