摘要 |
<p>The present invention features compositions and methods related to increasing the solubility and enzymatic activity of GalNAc-a-2,6-sialyltransferase I (STÌGalNAcI) proteins expressed in prokaryotic host cells. Methods for increasing the solubility of STÌGalNAcI polypeptides include modifying cysteine residues, modifying N-linked glycosylation sites, deleting polypeptide regions, and constructing chimeric polypeptides comprising sequences from a STÌGalNAcI and another protein, for example, a Gal-ß- l,3GalNAc-a-2,3-sialyltransferase (ST3GalI) and a STÌGalNAcI. The invention also features nucleic acids encoding such improved polypeptides, as well as vectors, host cells, expression systems, and methods of expressing and using such polypeptides.</p> |