BACKGROUND:  A major barrier to working effectively with many proteins, particularly membrane proteins, is the inability to obtain large quantities of pure protein. Oftentimes, proteins cannot be produced effectively in standard E. coli strains. Current methods to improve expression are generally employed in an ad hoc fashion, including the alteration of growth media, temperature, or induction levels. In addition, fusion to other proteins can help expression. Although these techniques offer some improvements, there have been no universal solutions and membrane protein production continues to be a considerable obstacle. There is a need for a straightforward approach in achieving high yields of recombinant expression.

INNOVATION:  UCLA researchers have identified a direct and rational method that selects for mutants of E. coli that can better produce a targeted protein. Using this method, five mutants that improved the expression of a variety of membrane protein were obtained and characterized.

POTENTIAL APPLICATIONS 

• Selection system can be used to select for new E. coli mutant strains that improve the production of targeted proteins
• Already isolated E. coli strains can be used to express targeted proteins

ADVANTAGES

• Higher yield of pure protein from recombinant expression
• Improved expression of targeted proteins
• Direct and rational approach

DEVELOPMENT-TO-DATE:  The selection method has been fully implemented, with improvements in development. There are plans to create a library of EXP strains for diverse targets that will provide a higher likelihood of expression success.

Related Papers (Selected)

• Gendel EM, Zhao A, Boulting G, Kim H-Y, Balmotis MA, Seligman LM, Nakamoto RK and Bowie JU, Genetic Selection System for Improving Recombinant Membrane Protein Expression in E. coli, submitted

Reference: UCLA Case No. 2009-187