title: Magnetically Directed Two-Dimensional Crystallization of OmpF Membrane Proteins in Block Copolymers.
abstract: Two-dimensional (2D) alignment and crystallization of membrane proteins (MPs) is increasingly important in characterizing their three-dimensional (3D) structure, in designing pharmacological agents, and in leveraging MPs for biomimetic devices. Large, highly ordered MP 2D crystals in block copolymer (BCP) matrices are challenging to fabricate, but a facile and scalable technique for aligning and crystallizing MPs in thin-film geometries would rapidly translate into applications. This work introduces a novel method to grow larger and potentially better ordered 2D crystals by performing the crystallization process in the presence of a strong magnetic field. We demonstrate the efficacy of this approach using a β-barrel MP, outer membrane protein F (OmpF), in short-chain polybutadiene-poly(ethylene oxide) (PB-PEO) membranes. Crystals grown in a magnetic field were up to 5 times larger than conventionally grown crystals, and a signal-to-noise (SNR) analysis of diffraction peaks in Fourier transforms of specimens imaged by negative-stain electron microscopy (EM) and cryo-EM showed twice as many high-SNR diffraction peaks, indicating that the magnetic field also improves crystal order.
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Klara
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Saboe
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Sines
authors.affiliation: Deparment of Civil & Environmental Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Mahnoush
authors.initials: M
authors.lastname: Babaei
authors.affiliation: Department of Cell Biology, Harvard Medical School , Boston, Massachusetts 02115, United States.
authors.forename: Po-Lin
authors.initials: PL
authors.lastname: Chiu
authors.affiliation: Department of Cell Biology, Harvard Medical School , Boston, Massachusetts 02115, United States.|Howard Hughes Medical Institute, Harvard Medical School , Boston, Massachusetts 02115, United States.
authors.forename: Rita
authors.initials: R
authors.lastname: DeZorzi
authors.affiliation: Deparment of Civil & Environmental Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Dayal
authors.affiliation: Department of Cell Biology, Harvard Medical School , Boston, Massachusetts 02115, United States.|Howard Hughes Medical Institute, Harvard Medical School , Boston, Massachusetts 02115, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Walz
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.|Deparment of Civil & Environmental Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.|Department of Engineering & Public Policy, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Meagan S
authors.initials: MS
authors.lastname: Mauter
mesh_terms: D003460:Crystallization; D008280:Magnetics; D011108:Polymers / Q000737:chemistry*; D018272:Porins / Q000737:chemistry*
chemical_list: C109237:OmpF protein; D011108:Polymers; D018272:Porins