Disclosed herein are proteins, methods, cells, engineered microorganisms, and kits for generating a modified nucleoside triphosphate transporter from Phaeodactylum tricornutum. Also disclosed herein proteins, methods, cells, engineered microorganisms, and kits for production of a nucleic acid molecule that comprises an unnatural nucleotide utilizing a modified nucleoside triphosphate transporter from Phaeodactylum tricornutum.