Methods for identifying novel antibiotics and related compositions

A method for identifying agents that inhibit a lipoprotein signal peptidase (Lsp), comprising (a) contacting a recombinantly-produced and purified Lsp with a Lsp substrate in the presence of test compounds, and (b) detecting inhibition by one or more test compounds of Lsp cleavage of the substrate;

• thereby identifying agents that inhibit the lipoprotein signal peptidase (Lsp).

The method of claim 14, wherein the His-tagged fusion protein comprises an N-terminal His6-tag.

The method of claim 16, wherein the detergent is n-Dodecyl β-D-maltoside (DDM).

A method for inhibiting Lsp catalytic activity in a bacterial cell, comprising contacting the bacterial cell with an Lsp inhibitor compound under conditions to allow the compound to inhibit Lsp that is present in the cell, wherein the Lsp inhibitor compound is Compound SR-010000270728-1, Compound BBS-8 or Compound BBS-20, or a functional variant thereof.

A method for inhibiting bacterial growth and treating bacterial infection in a subject, comprising administering to the subject afflicted with a bacterial infection a pharmaceutical composition comprising a therapeutically effective amount of an Lsp inhibitor compound, thereby inhibiting bacterial growth and treating bacterial infection in the subject;

• wherein the Lsp inhibitor compound is Compound SR-010000270728-1, Compound BBS-8 or Compound BBS-20, or a functional variant thereof.

A method of generating an active detergent-solubilized transmembrane enzyme capable of measuring catalytic activity in an assay system, comprising (a) constructing an expression vector capable of expressing the active transmembrane enzyme;

• (b) expressing said active transmembrane enzyme from said vector;
• and (c) solubilizing and purifying the active transmembrane enzyme in a detergent based system;
• thereby generating an active transmembrane detergent-solubilized enzyme capable of measuring specific catalytic activity in an assay system.

A method for identifying an Lsp-inhibitory compound with improved properties, comprising (a) synthesizing one or more structural analogs of a lead Lsp inhibitor compound;

• (b) performing a functional assay on the analogs to identify an analog that has an improved biological or pharmaceutical property relative to that of the lead compound;
• thereby identifying an Lsp-inhibitory compound with improved properties.