Inner Residues in the Transmembrane Helix Bundle are More Conservative

摘要

Molecular structures of the membrane proteins are of great importance to the functions of the biomem-branes. However, there is a small number of membrane proteins whose three-dimensional structures are determined. The properties of the conserved aminoacid residues in the transmembrane helices (TMH) are valuable to investigate for the prediction of the protein structures. It is known that a residue at a helix contact in the TMH bundle frequently changes into another residue with similar volume. Furthermore, it is noticed that volume of the residue near the center of the protein scarcely changes. In this study, the conservation tendency of the residues is analyzed in several transmembrane protein families. It is shown that the residues are more conservative at the inner positions in the TMH bundle. The analysis presented here is also valid for the prediction of the membrane protein structures.