| 摘要 |
The present invention deals with examination of the alterability of part, or whole, of the surfaces of beta sheet-based protein structures, focusing especially on enzymes. The alteration is done by supplanting/transplanting a part, or whole, of the surface of one protein onto the surface of a homologous protein of superimposable polypeptide backbone, by exploiting the structural features of beta sheets to alter only the regions of the surface involved in substrate/ligand binding and catalysis. The transplantation involves replacement of a selected set of non-contiguous residues constituting the surface regions desired to be altered in one enzyme/protein, by a set of non-contiguous residues located at analogous positions in the other enzyme/protein, in a manner that is likely to facilitate folding and function of the new protein formed by combining residues from both enzymes/proteins. The present invention also deals with using this surface engineering approach to selectively combine enzyme/protein characteristics from different domains of life that are not ordinarily combined by natural evolution, such as the creation of novel proteins that retains the bulk of the thermostable scaffold of a thermophile enzyme onto which the active surface of a mesophile homolog is transplanted, so as to create a thermo-stable protein with meso-active functional characteristics of pH and temperature of optimal function.
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