title: Influence of fluorination on protein-engineered coiled-coil fibers.
abstract: We describe the design and characterization of fluorinated coiled-coil proteins able to assemble into robust nano- and microfibers. Fluorination is achieved biosynthetically by residue-specific incorporation of 5,5,5-trifluoroleucine (TFL). The fluorinated proteins C+TFL and Q+TFL are highly α-helical as confirmed via circular dichroism (CD) and more resistant to thermal denaturation compared to their nonfluorinated counterparts, C and Q. The fluorinated proteins demonstrate enhanced fiber assembly at pH 8.0 with higher order structure in contrast to nonfluorinated proteins, which are unable to form fibers under the same conditions. Ionic strength dependent fiber assembly is observed for fluorinated as well as wild-type proteins in which the fluorinated proteins exhibited more stable, thicker fibers. The fluorinated and nonfluorinated proteins reveal metal ion-dependent small molecule recognition and supramolecular assemblies. In the presence of Zn (II), enhanced thermal stability and fiber assembly is observed for the fluorinated proteins and their nonfluorinated counterparts. Whereas Ni (II) promotes aggregation with no fiber assembly, the stabilization of α-helix by Zn (II) results in enhanced binding to curcumin by the fluorinated proteins. Surprisingly, the nonfluorinated proteins exhibit multiple-fold increase in curcumin binding in the presence of Zn (II). In the context of the growing number of protein-based fiber assemblies, these fluorinated coiled-coil proteins introduce a new paradigm in the development of highly stable, robust self-assembling fibers under more physiologically relevant pH conditions that promotes the binding and release of small molecules in response to external cues.
authors: †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.
authors: Haresh T
authors: HT
authors: More
authors: †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.
authors: Kevin S
authors: KS
authors: Zhang
authors: †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.
authors: Nikita
authors: N
authors: Srivastava
authors: †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.
authors: Joseph A
authors: JA
authors: Frezzo
authors: †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.|∫Department of Biochemistry, SUNY Downstate Medical Center, Brooklyn, New York 11203, United States.|§Department of Chemistry, New York University, New York, New York 10003, United States.
authors: Jin K
authors: JK
authors: Montclare
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D064236:Cartilage Oligomeric Matrix Protein / Q000737:chemistry* / Q000378:metabolism; D003474:Curcumin / Q000737:chemistry; D054879:Halogenation; D007930:Leucine / Q000031:analogs & derivatives / Q000737:chemistry; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D066329:Protein Aggregates; D011485:Protein Binding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D015032:Zinc / Q000737:chemistry
chemical_list: D064236:Cartilage Oligomeric Matrix Protein; D066329:Protein Aggregates; C035177:5',5',5'-trifluoroleucine; D007930:Leucine; D003474:Curcumin; D015032:Zinc