Overnight Express Autoinduction System 2 provides a complete, chemically defined medium for high-level protein expression with the pET System and other IPTG-inducible expression systems without the need to monitor cell growth. All system components have a known chemical composition, resulting in consistent product performance and the elimination of lot-to-lot variability. System 2 also features the capability to label proteins with elenomethionine (Se-Met) for downstream crystallization and x-ray diffraction studies.

The system includes six concentrated sterile solutions: OnEx™ solutions 1 through 6. OnEx Solutions 1, 2, and 3 are the same components included in the Overnight Express System 1. OnEx Solution 4 provides trace metals to minimize growth limitations associated with mineral deficiencies and satisfy the metal requirements of metal-containing target proteins even at high expression levels. OnEx Solution 5 is a mixture of amino acids lacking methionine. OnEx Solution 6 is a separate methionine solution. Sufficient methionine (Met) is provided to support growth of the Met auxotroph B834 while providing the ability to reduce the level of unlabeled Met for selenomethionine incorporation by Met auxotrophs.

The Overnight Express Autoinduction System 2 is extremely convenient for routine expression of proteins in multiple cultures and is ideal for high-throughput parallel analysis of protein expression, solubility screening, and purification from multiple expression clones. The tedium of preparing a defined medium from dozens of components has been simplified with the ready-to-use sterile solutions included in the Overnight Express Autoinduction System 2.

Two Overnight Express™ Autoinduction Systems (System 1 and System 2) are available, both featuring high-level protein production in the pET and other IPTG-inducible bacterial expression systems without the need to monitor cell growth. Cell mass and target protein yield are often increased several-fold as compared with conventional protocols using induction with IPTG. Also available is Overnight Express Instant TB Medium.

• High cell densities and protein expression levels
• Complete chemically defined medium; minimal lot-to-lot variability
• No need to monitor cell growth rate or add inducer
• Ideal for Se-Met labeling of proteins to be crystallized for x-ray diffraction studies
• Ideal for pET Expression System or other IPTG-inducible bacterial systems
• Induction of numerous expression clones simultaneously
• Compatible with cultures grown in flasks, culture tubes, and deep-well plates
• Minimal sample handling