Methods for the identification of inhibitors of threonine synthase as antibiotics

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) contacting said test compound with at least one polypeptide selected from the group consisting of:
• a polypeptide having at least ten consecutive amino acids of a fungal Threonine synthase, a polypeptide having at least 50% sequence identity with a fungal Threonine synthase, and a polypeptide having at least 10% of the activity thereof;
• and
• b) detecting the presence and/or absence of binding between said test compound and said polypeptide;
• wherein binding indicates that said test compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) contacting O-phospho-L-homoserine and water with a Threonine synthase;
• b) contacting O-phospho-L-homoserine and water with Threonine synthase and said test compound;
• and
• c) determining the change in concentration for at least one of the following:
• O-phospho-L-homoserine, L-threonine, orthophosphate, and water;
• wherein a change in concentration for any of the above substances between steps (a) and (b) indicates that said test compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) contacting L-threonine and orthophosphate with a Threonine synthase;
• b) contacting L-threonine and orthophosphate with a Threonine synthase and said test compound;
• and
• c) determining the change in concentration for at least one of the following:
• O-phospho-L-homoserine, L-threonine, orthophosphate, and water;
• wherein a change in concentration for any of the above substances between steps (a) and (b) indicates that said test compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) contacting O-phospho-L-homoserine and water with a polypeptide selected from the group consisting of:
• a polypeptide having at least 50% sequence identity with Threonine synthase, a polypeptide having at least 50% sequence identity with a Threonine synthase and having at least 10% of the activity thereof, and a polypeptide comprising at least 100 consecutive amino acids of a Threonine synthase
• b) contacting O-phospho-L-homoserine and water with said polypeptide and said test compound;
• and
• c) determining the change in concentration for at least one of the following:
• O-phospho-L-homoserine, L-threonine, orthophosphate, and water;
• wherein a change in concentration for any of the above substances between steps (a) and (b) indicates that said test compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) contacting L-threonine and orthophosphate with a polypeptide selected from the group consisting of:
• a polypeptide having at least 50% sequence identity with a Threonine synthase, a polypeptide having at least 50% sequence identity with a Threonine synthase and at least 10% of the activity thereof, and a polypeptide comprising at least 100 consecutive amino acids of a Threonine synthase
• b) contacting L-threonine and orthophosphate, with said polypeptide and said test compound;
• and
• c) determining the change in concentration for at least one of the following:
• O-phospho-L-homoserine, L-threonine, orthophosphate, and water;
• wherein a change in concentration for any of the above substances between steps (a) and (b) indicates that said test compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) measuring the expression of a Threonine synthase in a fungal cell, cells, tissue, or organism in the absence of said compound;
• b) contacting said fungal cell, cells, tissue, or organism with said test compound and measuring the expression of said Threonine synthase in said fungus or fungal cell;
• c) comparing the expression of Threonine synthase in steps (a) and (b);
• wherein a lower expression in the presence of said test compound indicates that said compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• a) providing cells having one form of a gene in the L-threonine biochemical and/or genetic pathway and providing comparison cells having a different form of said gene.
• b) contacting said cells and comparison cells with a said test compound,
• c) determining the growth of said cells and comparison cells in the presence of said test compound;
• wherein a difference in growth between said cells and said comparison cells in the presence of said compound indicates that said compound is a candidate for an antibiotic.

A method for identifying a test compound as a candidate for an antibiotic, comprising:

• (a) providing paired growth media;
• comprising a first medium and a second medium, wherein said second medium contains a higher level of L-threonine than said first medium;
• (b) contacting an organism with said test compound;
• (c) inoculating said first and second media with said organism;
• and
• (d) determining the growth of said organism;
• wherein a difference in growth of the organism between said first and second media indicates that said test compound is a candidate for an antibiotic.