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

Abstract
The LYP1 gene of Saccharomyces cerevisiae was cloned by complementation in lysine‐permease‐deficint 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.