APPLICATIONS OF TECHNOLOGY:

• Biomass or biofuel production
• Carbon dioxide sequestration, nitrogen fixation
• Bioremediation
• Protein purification
• Chemical and pharmaceutical production
• Other synthetic biology applications

ADVANTAGES:

• Increases efficiency of catalytic pathways
• Provides protective microenvironments
• Enables new combinations and scaffolding of enzymes
• Compatible with biological and non-biological systems

ABSTRACT:

Cheryl Kerfeld and James Kinney at Berkeley Lab have identified peptide targeting signals that can direct selected enzymes, metabolites, and other macromolecules to microcompartments or scaffolds used to engineer reactions in cells and non-cellular systems.

To achieve methods of inserting microcompartments into cells and nonliving vesicles to engineer desirable reactions, a targeting signal can be required to bring the enzymes and necessary reaction components to the microcompartment or scaffold. Potential targeting signals identified by Kerfeld and Kinney may serve such a purpose.

The scientists first analyzed the amino acid sequences of enzymes in bacterial microcompartments with diverse functions such as carbon fixation, ethanolamine catabolism, glycyl-radical-based reactions and vitamin-B12-based reactions, among others. The biophysical properties of certain amino acid sequences and an associated linker region were highly conserved among the enzymes from various species and types of microcompartments. These sequences are proposed to bind the conserved hexameric units that, like bathroom tiles, make up the walls of microcompartments. Therefore, these and similar sequences could be attached to desired molecules to direct them to microcompartments or scaffolds.

Microcompartments are protein-based organelles that occur naturally in many bacteria and function as enclosed scaffolds to colocalize enzymes, thereby increasing reaction cascade efficiency. Microcompartment proteins can also be used as two-dimensional molecular layers, i.e., unenclosed scaffolds. Encapsulating reactions within microcompartments protects the surrounding cell from potentially toxic intermediates and conversely protect the enzymes, intermediates, and products from the potentially destabilizing components of the cytoplasm, such as oxygen.

Technologies with microcompartments and scaffolds may be used to improve nonbiological catalysis and introduce new or enhanced metabolic activity to prokaryotes and eukaryotes. The Berkeley Lab peptide sequences provide an essential element in the development of these technologies.

	A schematic showing hexameric proteins (green and yellow) that constitute scaffolds or the walls of microcompartments that can be used to engineer reaction cascades. The targeting peptides (blue rectangles) can be attached to proteins or other biomolecules (red cylinders) needed in the cascades and direct them to the putative binding sites on the sides of the hexamers.

STATUS: Patent pending. Available for licensing or collaborative research.

DEVELOPMENT STATUS: Bench scale demonstration performed.

REFERENCE NUMBER: IB-2785

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

• Custom Engineered Microcompartments for Enzyme Efficiency, IB-2626

• Novel Biosynthetic Pathway for Production of Fatty Acid Derived Molecules, IB-2386, IB-2387

• Engineered Biosynthesis of Alternative Biodiesel Fuel in E. Coli and Yeast, EIB-2391

• Irreversible, Low Load Genetic Switches, EJIB-2593