------------------------------------------------------ URA 2055 ---------------- Author(s) : THIOULOUSE J.,LOBRY J.R. Co-inertia analysis of amino-acid physico-chemical properties and protein composition with the ADE package. Computer Applications in the Biosciences Serial Number : 11, 1995, pp. 321-329 Key-Words : CO-INERTIA ANALYSIS,MACINTOSH,ADE,AMINO-ACIDS,PROTEINS Abstract A multivariate analysis method called co-inertia analysis was used to determine the main relationships between two data tables having identical rows. This method is available in the ADE multivariate analysis package for Macintosh micro-computers. It was applied to two data sets, one containing the amino-acid composition of 999 E. coli proteins, and the other the values of 402 physico-chemical properties for the 20 natural amino-acids. There were strong relationships between amino-acid physico-chemical properties and the composition of proteins. The first common factor was hydrophobicity; it is linked to the biological environment of proteins, either in the cytoplasm (or outside the cell), or in the non polar environment of the phospholipid bilayer of biological membranes. The second factor linked the expressivity of protein genes and the propensity of amino-acids to form alpha helix / beta sheets. The third factor showed that heavy, aromatic amino-acids tend to be avoided, except when they are needed for structural or functional reasons. These results are discussed in terms of selective pressure acting on amino-acid composition of proteins. E-Mail : thioulou@biomserv.univ-lyon1.fr Laboratoire de Biometrie, Genetique et Biologie des Populations (URA 2055) - Univ. C. Bernard LYON I - 69622 VILLEURBANNE CEDEX