Methods and reagents to label bacteria and virus and identify their interacting proteins

A method of identifying proteins interactions between a host and a pathogen microbe in real time, comprising the steps of:

• a) providing a chemo-proteomic probe comprising:
• a functional group for conjugating to a surface protein of a live microbe under a physiological condition;
• a photo-reactive group for covalent cross-linking to an interacting protein of a host cell;
• and a tag for isolating the cross-linked complex of the surface protein of said live microbe and the interacting protein of a host cell for qualitative and quantitative analyses;
• b) allowing the microbe to infect the host;
• c) crosslinking at fixed time points so that the interacting proteins of the host cells have sufficiently interacted with the surface proteins of the pathogen microbe;
• d) isolating the cross-linked complex of the surface proteins of said pathogen microbe and the interacting cell proteins of a host utilizing the tag;
• and
• e) performing qualitative and quantitative analyses of the isolated cross-linked protein complex.

A kit for identifying interactions between a host cell and a pathogen microbe in real time, comprising:

• a) a chemo-proteomic probe comprising:
• a functional group for conjugating to a surface protein of a live microbe under a physiological condition;
• a photo-reactive group for covalent cross-linking to an interacting cell protein of a host;
• and a tag for isolating the cross-linked complex of the surface protein of said live microbe and the interacting cell protein of a host for qualitative and quantitative proteomics analyses;
• and
• b) reagents for enabling said conjugation and crosslinking.