A simple method for displaying the hydropathic character of a protein-英文文献.pdf

J. Mol. Biol. (1982) 157, 105-132 A Simple Method for Displaying the Hydropathic Character of a Protein JACK KYTE AND RUSSELLF. DOOLITTLE Department of Chemistry University of California, San Diego, La Jolla, Calif. 92093, 1J.S.,4. (Received 8 August 1981~ and in revised form 25 January 1982) A computer program that progressively evaluates the hydrophilicity and hydrophobicity of a protein along its amino acid sequence has been devised. For this purpose, a hydropathy scale has been composed wherein the hydrophilic and hydrophobic properties of each of the 20 amino acid side-chains is taken into consideration. The scale is based on an amalgam of experimental observations derived from the literature. The program uses a moving-segment approach that continuously determines the average hydropathy within a segment of predetermined length as it advances through the sequence. The consecutive scores are plotted from the amino to the carboxy terminus. At the same time, a midpoint line is printed that corresponds to the grand average of the hydropathy of the amino acid compositions found in most of the sequenced proteins. In the case of soluble, globular proteins there is a remarkable correspondence between the interior portions of their sequence and the regions appearing on the hydrophobic side of the midpoint line, as well as the exterior portions and