Modulating Supramolecular Assemblies and Mechanical Properties of Engineered Protein Materials by Fluorinated Amino Acids

Abstract

Here we describe the biosynthesis and characterization of fluorinated protein block polymers comprised of the two self-assembling domains (SADs): elastin (E) and the coiled-coil region of cartilage oligomeric matrix proteins (C). Fluorination is achieved by residue-specific incorporation of p-fluorophenylalanine (pFF) to create pFF-EC, pFF-CE, and pFF-ECE. Global fluorination results in downstream effects on the temperature-dependent secondary structure, supramolecular assembly, and bulk mechanical properties. The impact of fluorination on material properties also differs depending on the orientation of the block configurations as well as the number of domains in the fusion. These studies suggest that integration of fluorinated amino acids within protein materials can be employed to tune the material properties, especially mechanical integrity.

Gene delivery from supercharged coiled-coil protein and cationic lipid hybrid complex

“…To express the CSP and COMPcc proteins, the E. coli strains AF-IQ [43, 44] and XL-1 blue were used for transformation of CSP and COMPcc, respectively. Starter culture of CSP and COMPcc were made in 5 mL of LB containing ampicillin (200 μg/mL) and chloramphenicol (35 μg/mL) and LB containing ampicillin (200 μg/mL), respectively and incubated overnight at 37 °C and 350 rpm.…”

Protein‐Engineered Functional Materials

“…Although fluorine atoms are not found in any of the twenty amino acids, incorporation of fluorine analogues into the protein have been shown to enhance their stability with improvements in physical and mechanical properties . With the help of modern protein engineering incorporation techniques, fluorine can be readily introduced into a protein structure.…”

“…Montclare and co‐workers have studied the impact of fluorination on fiber assembly, supramolecular assemblies and mechanical properties . Using the α‐helical coiled–coils C and Q mentioned previously, incorporation of trifluoroleucine (TFL) is achieved via residue‐specific incorporation ( Table 5 , Figure a).…”

“…The resulting C‐TFL and Q‐TFL exhibits an increase in α‐helicity, resulting in enhanced drug binding ability, improved thermal stability and enhanced fiber assembly at pH 8.0 compared to their nonfluorinated variants . Fluorination of the α‐helix‐elastin protein polymer through the residue‐specific incorporation of p ‐fluorophenylalanine (pFF) results in pFF‐EC, pFF‐CE, and pFF‐ECE (Table , Figure b) . As fluorination affects the properties and stability of the target proteins, it has been used to tune the mechanical properties of the proteins.…”

Improved Stability and Half‐Life of Fluorinated Phosphotriesterase Using Rosetta

“…The expansion of the genetic code has led to the biosynthetic incorporation of a wide range of noncanonical amino acids (NCAAs) into proteins 1. In particular, fluorinated amino acids (FAAs) have been integrated into small coiled‐coil proteins,2 a range of enzymes,3 and biomaterials 4. Although incorporation of FAAs into a target protein can lead to enhanced function or stability, in some cases loss of activity or stability occurs, and further improvements to the artificial protein have been made by rational mutagenesis3c and directed evolution strategies 5.…”