SFAPS: an R package for structure/function analysis of protein sequences based on informational spectrum method.

The R package SFAPS has been developed for structure/function analysis of protein sequences based on information spectrum method. The informational spectrum method employs the electron-ion interaction potential parameter as the numerical representation for the protein sequence, and obtains the characteristic frequency of a particular protein interaction after computing the Discrete Fourier Transform for protein sequences. The informational spectrum method is often used to analyze protein sequences, so we developed this software tool, which is implemented as an add-on package to the freely available and widely used statistical language R. Our package is distributed as open source code for Linux, Unix and Microsoft Windows. It is released under the GNU General Public License. The R package along with its source code and additional material are freely available at http://mlsbl.tongji.edu.cn/DBdownload.asp.