Cloning and sequencing of the Saccharomyces cerevisiae gene LYP1 coding for a lysine-specific permease

The LYP1 gene of Saccharomyces cerevisiae was cloned by complementation in lysine-permease-deficient recipient yeast cells, and its nucleotide sequence was determined. An open reading frame of 1833 nucleotides was found encoding a polypeptide of 611 amino acids, with a calculated molecular weight of 68 118. Analysis of the deduced primary structure of the protein revealed ten membrane-spanning regions and three potential N-glycosylation sites. Analysis of the deduced sequence of protein LYP1 indicates homology with other yeast amino-acid permeases, in particular with CAN1, and also the lysine-specific permease of Escherichia coli. The strain transformed by a multi-copy plasmid harbouring the LYP1 gene, showed a 20-fold increase in the maximum velocity of lysine uptake over that in the wild type, with no changes in the affinity of the permease for its substrate.