Chloramphenicol resistant split protein and uses thereof

A method of identifying a test polypeptide which affects the binding between a first polypeptide and a second polypeptide, comprising:

• (a) culturing a population of bacterial cells in a culture medium with the test polypeptide and chloramphenicol, wherein the bacterial cell population expresses an amount of chloramphenicol acetyl transferase (CAT) protein which correlates with binding of the first polypeptide to the second polypeptide;
• and
• wherein the bacterial cell population comprises (i) a first fusion protein comprising the first polypeptide and an N-terminal fragment of the CAT protein consisting of the amino acid sequence as set forth in SEQ ID NO:
• 2 or 6;
• and (ii) a second fusion protein comprising the second polypeptide and a C-terminal fragment of the CAT protein consisting of the amino acid sequence as set forth in SEQ ID NO:
• 3 or 7;
• and
• (b) analyzing survival or growth of the bacterial cells in the culture medium, wherein an increase or decrease in the survival or growth of the bacterial cells as compared to survival or growth of the bacterial cells in the absence of the test polypeptide indicates that the test polypeptide affects the binding between the first polypeptide and the second polypeptide;
• thereby identifying a test polypeptide that affects the binding between the first polypeptide and the second polypeptide.