1
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Han K, Zhang Z, Tezcan FA. Spatially Patterned, Porous Protein Crystals as Multifunctional Materials. J Am Chem Soc 2023; 145:19932-19944. [PMID: 37642457 DOI: 10.1021/jacs.3c06348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
While the primary use of protein crystals has historically been in crystallographic structure determination, they have recently emerged as promising materials with many advantageous properties such as high porosity, biocompatibility, stability, structural and functional versatility, and genetic/chemical tailorability. Here, we report that the utility of protein crystals as functional materials can be further augmented through their spatial patterning and control of their morphologies. To this end, we took advantage of the chemically and kinetically controllable nature of ferritin self-assembly and constructed core-shell crystals with chemically distinct domains, tunable structural patterns, and morphologies. The spatial organization within ferritin crystals enabled the generation of patterned, multi-enzyme frameworks with cooperative catalytic behavior. We further exploited the differential growth kinetics of ferritin crystal facets to assemble Janus-type architectures with an anisotropic arrangement of chemically distinct domains. These examples represent a step toward using protein crystals as reaction vessels for complex multi-step reactions and broadening their utility as functional, solid-state materials. Our results demonstrate that morphology control and spatial patterning, which are key concepts in materials science and nanotechnology, can also be applied for engineering protein crystals.
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Affiliation(s)
- Kenneth Han
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Zhiyin Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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2
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Hoffnagle AM, Tezcan FA. Atomically Accurate Design of Metalloproteins with Predefined Coordination Geometries. J Am Chem Soc 2023; 145:14208-14214. [PMID: 37352018 PMCID: PMC10439731 DOI: 10.1021/jacs.3c04047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2023]
Abstract
We report a new computational protein design method for the construction of oligomeric protein assemblies around metal centers with predefined coordination geometries. We apply this method to design two homotrimeric assemblies, Tet4 and TP1, with tetrahedral and trigonal-pyramidal tris(histidine) metal coordination geometries, respectively, and demonstrate that both assemblies form the targeted metal centers with ≤0.2 Å accuracy. Although Tet4 and TP1 are constructed from the same parent protein building block, they are distinct in terms of their overall architectures, the environment surrounding the metal centers, and their metal-based reactivities, illustrating the versatility of our approach.
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Affiliation(s)
- Alexander M. Hoffnagle
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
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3
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Alberstein RG, Prelesnik JL, Nakouzi E, Zhang S, De Yoreo JJ, Pfaendtner J, Tezcan FA, Mundy CJ. Discrete Orientations of Interfacial Waters Direct Crystallization of Mica-Binding Proteins. J Phys Chem Lett 2023; 14:80-87. [PMID: 36573690 DOI: 10.1021/acs.jpclett.2c02948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Understanding the basis of templated molecular assembly on a solid surface requires a fundamental comprehension of both short- and long-range aqueous response to the surface under a variety of solution conditions. Herein we provide a detailed picture of how the molecular-scale response to different mica surfaces yields distinct solvent orientations that produce quasi-static directional potentials onto which macromolecules can adsorb. We connect this directionality to observed (a)symmetric epitaxial alignment of designed proteins onto these surfaces, corroborate our findings with 3D atomic force microscopy experiments, and identify slight differences in surface structure as the origin of this effect. Our work provides a detailed picture of the intrinsic electrolyte response in the vicinity of mineral interfaces, with clear predictions for experiment, and highlights the role of solvent on the predictive assembly of hierarchical materials on mineral surfaces.
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Affiliation(s)
- Robert G Alberstein
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Jesse L Prelesnik
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Elias Nakouzi
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Shuai Zhang
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - James J De Yoreo
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Jim Pfaendtner
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
- Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Christopher J Mundy
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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4
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Rutledge HL, Field MJ, Rittle J, Green MT, Akif Tezcan F. Role of Serine Coordination in the Structural and Functional Protection of the Nitrogenase P-Cluster. J Am Chem Soc 2022; 144:22101-22112. [PMID: 36445204 PMCID: PMC9957664 DOI: 10.1021/jacs.2c09480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Nitrogenase catalyzes the multielectron reduction of dinitrogen to ammonia. Electron transfer in the catalytic protein (MoFeP) proceeds through a unique [8Fe-7S] cluster (P-cluster) to the active site (FeMoco). In the reduced, all-ferrous (PN) state, the P-cluster is coordinated by six cysteine residues. Upon two-electron oxidation to the P2+ state, the P-cluster undergoes conformational changes in which a highly conserved oxygen-based residue (a Ser or a Tyr) and a backbone amide additionally ligate the cluster. Previous studies of Azotobacter vinelandii (Av) MoFeP revealed that when the oxygen-based residue, βSer188, was mutated to a noncoordinating residue, Ala, the P-cluster became redox-labile and reversibly lost two of its eight Fe centers. Surprisingly, the Av strain with a MoFeP variant that lacked the serine ligand (Av βSer188Ala MoFeP) displayed the same diazotrophic growth and in vitro enzyme turnover rates as wild-type Av MoFeP, calling into question the necessity of this conserved ligand for nitrogenase function. Based on these observations, we hypothesized that βSer188 plays a role in protecting the P-cluster under nonideal conditions. Here, we investigated the protective role of βSer188 both in vivo and in vitro by characterizing the ability of Av βSer188Ala cells to grow under suboptimal conditions (high oxidative stress or Fe limitation) and by determining the tendency of βSer188Ala MoFeP to be mismetallated in vitro. Our results demonstrate that βSer188 (1) increases Av cell survival upon exposure to oxidative stress in the form of hydrogen peroxide, (2) is necessary for efficient Av diazotrophic growth under Fe-limiting conditions, and (3) may protect the P-cluster from metal exchange in vitro. Taken together, our findings suggest a structural adaptation of nitrogenase to protect the P-cluster via Ser ligation, which is a previously unidentified functional role of the Ser residue in redox proteins and adds to the expanding functional roles of non-Cys ligands to FeS clusters.
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Affiliation(s)
- Hannah L. Rutledge
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Mackenzie J. Field
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Jonathan Rittle
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Michael T. Green
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.,Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697, United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States.,Corresponding Author:
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5
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Abstract
Selective metal binding is a key requirement not only for the functions of natural metalloproteins but also for the potential applications of artificial metalloproteins in heterogeneous environments such as cells and environmental samples. The selection of transition-metal ions through protein design can, in principle, be achieved through the appropriate choice and the precise positioning of amino acids that comprise the primary metal coordination sphere. However, this task is made difficult by the intrinsic flexibility of proteins and the fact that protein design approaches generally lack the sub-Å precision required for the steric selection of metal ions. We recently introduced a flexible/probabilistic protein design strategy (MASCoT) that allows metal ions to search for optimal coordination geometry within a flexible, yet covalently constrained dimer interface. In an earlier proof-of-principle study, we used MASCoT to generate an artificial metalloprotein dimer, (AB)2, which selectively bound CoII and NiII over CuII (as well as other first-row transition-metal ions) through the imposition of a rigid octahedral coordination geometry, thus countering the Irving-Williams trend. In this study, we set out to redesign (AB)2 to examine the applicability of MASCoT to the selective binding of other metal ions. We report here the design and characterization of a new flexible protein dimer, B2, which displays ZnII selectivity over all other tested metal ions including CuII both in vitro and in cellulo. Selective, anti-Irving-Williams ZnII binding by B2 is achieved through the formation of a unique trinuclear Zn coordination motif in which His and Glu residues are rigidly placed in a tetrahedral geometry. These results highlight the utility of protein flexibility in the design and discovery of selective binding motifs.
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6
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Spiegelman L, Bahn-Suh A, Montaño ET, Zhang L, Hura GL, Patras KA, Kumar A, Tezcan FA, Nizet V, Tsutakawa SE, Ghosh P. Strengthening of enterococcal biofilms by Esp. PLoS Pathog 2022; 18:e1010829. [PMID: 36103556 PMCID: PMC9512215 DOI: 10.1371/journal.ppat.1010829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/26/2022] [Accepted: 08/22/2022] [Indexed: 11/25/2022] Open
Abstract
Multidrug-resistant (MDR) Enterococcus faecalis are major causes of hospital-acquired infections. Numerous clinical strains of E. faecalis harbor a large pathogenicity island that encodes enterococcal surface protein (Esp), which is suggested to promote biofilm production and virulence, but this remains controversial. To resolve this issue, we characterized the Esp N-terminal region, the portion implicated in biofilm production. Small angle X-ray scattering indicated that the N-terminal region had a globular head, which consisted of two DEv-Ig domains as visualized by X-ray crystallography, followed by an extended tail. The N-terminal region was not required for biofilm production but instead significantly strengthened biofilms against mechanical or degradative disruption, greatly increasing retention of Enterococcus within biofilms. Biofilm strengthening required low pH, which resulted in Esp unfolding, aggregating, and forming amyloid-like structures. The pH threshold for biofilm strengthening depended on protein stability. A truncated fragment of the first DEv-Ig domain, plausibly generated by a host protease, was the least stable and sufficient to strengthen biofilms at pH ≤ 5.0, while the entire N-terminal region and intact Esp on the enterococcal surface was more stable and required a pH ≤ 4.3. These results suggested a virulence role of Esp in strengthening enterococcal biofilms in acidic abiotic or host environments. The bacterium Enterococcus faecalis is part of the normal microbiome but can also cause serious hospital-acquired infections. Enterococcus strains isolated from hospitals tend to have certain proteins not found in microbiome strains. Such proteins are therefore likely to be important in infection. We sought to understand the function of one such protein, Esp, through biochemical, biophysical, and microbiological techniques. We found that Esp, which is on the bacterial surface, formed amyloid-like fibrils that prevented removal of biofilms. Biofilms are bacterial communities enmeshed within a matrix, and form within the body or on inert objects like catheters. They promote infection by increasing resistance to antibiotics and interfering with clearance by the immune system. We observed that biofilms that lacked Esp could be disrupted much more easily than those that had Esp. We also found that Esp acted only at low pH (i.e., acidic conditions). Exactly how low a pH depended on whether Esp remained on the bacterial surface or was liberated from the surface by a protease, with a human intestinal protease being a likely cause of liberation. In summary, we found that Esp acts at acidic conditions and likely contributes to virulence by preventing the dispersal of biofilms.
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Affiliation(s)
- Lindsey Spiegelman
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Adrian Bahn-Suh
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Elizabeth T. Montaño
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Ling Zhang
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Greg L. Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Kathryn A. Patras
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Amit Kumar
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - F. Akif Tezcan
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Susan E. Tsutakawa
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Partho Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California, United States of America
- * E-mail:
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7
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Abstract
The enzyme nitrogenase couples adenosine triphosphate (ATP) hydrolysis to the multielectron reduction of atmospheric dinitrogen into ammonia. Despite extensive research, the mechanistic details of ATP-dependent energy transduction and dinitrogen reduction by nitrogenase are not well understood, requiring new strategies to monitor its structural dynamics during catalytic action. Here, we report cryo-electron microscopy structures of the nitrogenase complex prepared under enzymatic turnover conditions. We observe that asymmetry governs all aspects of the nitrogenase mechanism, including ATP hydrolysis, protein-protein interactions, and catalysis. Conformational changes near the catalytic iron-molybdenum cofactor are correlated with the nucleotide-hydrolysis state of the enzyme.
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Affiliation(s)
- Hannah L. Rutledge
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Brian D. Cook
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Hoang P. M. Nguyen
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Mark A. Herzik
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA,Corresponding author. (FAT), (MAH)
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA,Corresponding author. (FAT), (MAH)
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8
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Kakkis A, Golub E, Choi TS, Tezcan FA. Redox- and metal-directed structural diversification in designed metalloprotein assemblies. Chem Commun (Camb) 2022; 58:6958-6961. [PMID: 35642584 DOI: 10.1039/d2cc02440c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we describe a designed protein building block whose self-assembly behaviour is dually gated by the redox state of disulphide bonds and the identity of exogenous metal ions. This protein construct is shown - through extensive structural and biophysical characterization - to access five distinct oligomeric states, exemplifying how the complex interplay between hydrophobic, metal-ligand, and reversible covalent interactions could be harnessed to obtain multiple, responsive protein architectures from a single building block.
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Affiliation(s)
- Albert Kakkis
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - Eyal Golub
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - Tae Su Choi
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
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9
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Abstract
Crystalline materials are increasingly being used as platforms for encapsulating proteins to create stable, functional materials. However, the uptake efficiencies and stimuli-responsiveness of crystalline frameworks are limited by their rigidities. We have recently reported a new form of materials, polymer-integrated crystals (PIX), which combine the structural order of protein crystals with the dynamic, stimuli-responsive properties of synthetic polymers. Here we show that the crystallinity, flexibility, and chemical tunability of PIX can be exploited to encapsulate guest proteins with high loading efficiencies (up to 46% w/w). The electrostatic host-guest interactions enable reversible, pH-controlled uptake/release of guest proteins as well as the mutual stabilization of the host and the guest, thus creating a uniquely synergistic platform toward the development of functional biomaterials and the controlled delivery of biological macromolecules.
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Affiliation(s)
- Kenneth Han
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Youjeong Na
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Ling Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States.,Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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10
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Abstract
Selective metal coordination is central to the functions of metalloproteins:1,2 each metalloprotein must pair with its cognate metallocofactor to fulfil its biological role3. However, achieving metal selectivity solely through a three-dimensional protein structure is a great challenge, because there is a limited set of metal-coordinating amino acid functionalities and proteins are inherently flexible, which impedes steric selection of metals3,4. Metal-binding affinities of natural proteins are primarily dictated by the electronic properties of metal ions and follow the Irving-Williams series5 (Mn2+ < Fe2+ < Co2+ < Ni2+ < Cu2+ > Zn2+) with few exceptions6,7. Accordingly, metalloproteins overwhelmingly bind Cu2+ and Zn2+ in isolation, regardless of the nature of their active sites and their cognate metal ions1,3,8. This led organisms to evolve complex homeostatic machinery and non-equilibrium strategies to achieve correct metal speciation1,3,8-10. Here we report an artificial dimeric protein, (AB)2, that thermodynamically overcomes the Irving-Williams restrictions in vitro and in cells, favouring the binding of lower-Irving-Williams transition metals over Cu2+, the most dominant ion in the Irving-Williams series. Counter to the convention in molecular design of achieving specificity through structural preorganization, (AB)2 was deliberately designed to be flexible. This flexibility enabled (AB)2 to adopt mutually exclusive, metal-dependent conformational states, which led to the discovery of structurally coupled coordination sites that disfavour Cu2+ ions by enforcing an unfavourable coordination geometry. Aside from highlighting flexibility as a valuable element in protein design, our results illustrate design principles for constructing selective metal sequestration agents.
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Affiliation(s)
- Tae Su Choi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
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11
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Zhu J, Samperisi L, Kalaj M, Chiong JA, Bailey JB, Zhang Z, Yu CJ, Sikma RE, Zou X, Cohen SM, Huang Z, Tezcan FA. Metal-hydrogen-pi-bonded organic frameworks. Dalton Trans 2022; 51:1927-1935. [PMID: 35019931 DOI: 10.1039/d1dt04278e] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis and characterization of a new series of permanently porous, three-dimensional metal-organic frameworks (MOFs), M-HAF-2 (M = Fe, Ga, or In), constructed from tetratopic, hydroxamate-based, chelating linkers. The structure of M-HAF-2 was determined by three-dimensional electron diffraction (3D ED), revealing a unique interpenetrated hcb-a net topology. This unusual topology is enabled by the presence of free hydroxamic acid groups, which lead to the formation of a diverse network of cooperative interactions comprising metal-hydroxamate coordination interactions at single metal nodes, staggered π-π interactions between linkers, and H-bonding interactions between metal-coordinated and free hydroxamate groups. Such extensive, multimodal interconnectivity is reminiscent of the complex, noncovalent interaction networks of proteins and endows M-HAF-2 frameworks with high thermal and chemical stability and allows them to readily undergo postsynthetic metal ion exchange (PSE) between trivalent metal ions. We demonstrate that M-HAF-2 can serve as versatile porous materials for ionic separations, aided by one-dimensional channels lined by continuously π-stacked aromatic groups and H-bonding hydroxamate functionalities. As an addition to the small group of hydroxamic acid-based MOFs, M-HAF-2 represents a structural merger between MOFs and hydrogen-bonded organic frameworks (HOFs) and illustrates the utility of non-canonical metal-coordinating functionalities in the discovery of new bonding and topological patterns in reticular materials.
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Affiliation(s)
- Jie Zhu
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Laura Samperisi
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden.
| | - Mark Kalaj
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Jerika A Chiong
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Zhiyin Zhang
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Chung-Jui Yu
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - R Eric Sikma
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Xiaodong Zou
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden.
| | - Seth M Cohen
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden.
| | - Zhehao Huang
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden.
| | - F Akif Tezcan
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden.
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12
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Zhu J, Avakyan N, Kakkis AA, Hoffnagle AM, Han K, Li Y, Zhang Z, Choi TS, Na Y, Yu CJ, Tezcan FA. Protein Assembly by Design. Chem Rev 2021; 121:13701-13796. [PMID: 34405992 PMCID: PMC9148388 DOI: 10.1021/acs.chemrev.1c00308] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Proteins are nature's primary building blocks for the construction of sophisticated molecular machines and dynamic materials, ranging from protein complexes such as photosystem II and nitrogenase that drive biogeochemical cycles to cytoskeletal assemblies and muscle fibers for motion. Such natural systems have inspired extensive efforts in the rational design of artificial protein assemblies in the last two decades. As molecular building blocks, proteins are highly complex, in terms of both their three-dimensional structures and chemical compositions. To enable control over the self-assembly of such complex molecules, scientists have devised many creative strategies by combining tools and principles of experimental and computational biophysics, supramolecular chemistry, inorganic chemistry, materials science, and polymer chemistry, among others. Owing to these innovative strategies, what started as a purely structure-building exercise two decades ago has, in short order, led to artificial protein assemblies with unprecedented structures and functions and protein-based materials with unusual properties. Our goal in this review is to give an overview of this exciting and highly interdisciplinary area of research, first outlining the design strategies and tools that have been devised for controlling protein self-assembly, then describing the diverse structures of artificial protein assemblies, and finally highlighting the emergent properties and functions of these assemblies.
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Affiliation(s)
| | | | - Albert A. Kakkis
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Alexander M. Hoffnagle
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Kenneth Han
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Yiying Li
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Zhiyin Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Tae Su Choi
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Youjeong Na
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Chung-Jui Yu
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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13
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Subramanian RH, Zhu J, Bailey JB, Chiong JA, Li Y, Golub E, Tezcan FA. Design of metal-mediated protein assemblies via hydroxamic acid functionalities. Nat Protoc 2021; 16:3264-3297. [PMID: 34050338 DOI: 10.1038/s41596-021-00535-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/15/2021] [Indexed: 02/05/2023]
Abstract
The self-assembly of proteins into sophisticated multicomponent assemblies is a hallmark of all living systems and has spawned extensive efforts in the construction of novel synthetic protein architectures with emergent functional properties. Protein assemblies in nature are formed via selective association of multiple protein surfaces through intricate noncovalent protein-protein interactions, a challenging task to accurately replicate in the de novo design of multiprotein systems. In this protocol, we describe the application of metal-coordinating hydroxamate (HA) motifs to direct the metal-mediated assembly of polyhedral protein architectures and 3D crystalline protein-metal-organic frameworks (protein-MOFs). This strategy has been implemented using an asymmetric cytochrome cb562 monomer through selective, concurrent association of Fe3+ and Zn2+ ions to form polyhedral cages. Furthermore, the use of ditopic HA linkers as bridging ligands with metal-binding protein nodes has allowed the construction of crystalline 3D protein-MOF lattices. The protocol is divided into two major sections: (1) the development of a Cys-reactive HA molecule for protein derivatization and self-assembly of protein-HA conjugates into polyhedral cages and (2) the synthesis of ditopic HA bridging ligands for the construction of ferritin-based protein-MOFs using symmetric metal-binding protein nodes. Protein cages are analyzed using analytical ultracentrifugation, transmission electron microscopy and single-crystal X-ray diffraction techniques. HA-mediated protein-MOFs are formed in sitting-drop vapor diffusion crystallization trays and are probed via single-crystal X-ray diffraction and multi-crystal small-angle X-ray scattering measurements. Ligand synthesis, construction of HA-mediated assemblies, and post-assembly analysis as described in this protocol can be performed by a graduate-level researcher within 6 weeks.
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Affiliation(s)
- Rohit H Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jie Zhu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jerika A Chiong
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Yiying Li
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Eyal Golub
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. .,Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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14
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Subramanian RH, Suzuki Y, Tallorin L, Sahu S, Thompson M, Gianneschi NC, Burkart MD, Tezcan FA. Enzyme-Directed Functionalization of Designed, Two-Dimensional Protein Lattices. Biochemistry 2021; 60:1050-1062. [PMID: 32706243 PMCID: PMC7855359 DOI: 10.1021/acs.biochem.0c00363] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The design and construction of crystalline protein arrays to selectively assemble ordered nanoscale materials have potential applications in sensing, catalysis, and medicine. Whereas numerous designs have been implemented for the bottom-up construction of protein assemblies, the generation of artificial functional materials has been relatively unexplored. Enzyme-directed post-translational modifications are responsible for the functional diversity of the proteome and, thus, could be harnessed to selectively modify artificial protein assemblies. In this study, we describe the use of phosphopantetheinyl transferases (PPTases), a class of enzymes that covalently modify proteins using coenzyme A (CoA), to site-selectively tailor the surface of designed, two-dimensional (2D) protein crystals. We demonstrate that a short peptide (ybbR) or a molecular tag (CoA) can be covalently tethered to 2D arrays to enable enzymatic functionalization using Sfp PPTase. The site-specific modification of two different protein array platforms is facilitated by PPTases to afford both small molecule- and protein-functionalized surfaces with no loss of crystalline order. This work highlights the potential for chemoenzymatic modification of large protein surfaces toward the generation of sophisticated protein platforms reminiscent of the complex landscape of cell surfaces.
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Affiliation(s)
- Rohit H. Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Yuta Suzuki
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
- Current address: Hakubi Center for Advanced Research, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, Japan, 606-8501
| | - Lorillee Tallorin
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Swagat Sahu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Matthew Thompson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
- Departments of Chemistry, Materials Science & Engineering, Biomedical Engineering, Chemistry of Life Processes Institute, International Institute for Nanotechnology, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, USA
| | - Nathan C. Gianneschi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
- Departments of Chemistry, Materials Science & Engineering, Biomedical Engineering, Chemistry of Life Processes Institute, International Institute for Nanotechnology, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, USA
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
- Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA
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15
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Kakkis A, Gagnon D, Esselborn J, Britt RD, Tezcan FA. Metal‐Templated Design of Chemically Switchable Protein Assemblies with High‐Affinity Coordination Sites. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Albert Kakkis
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive La Jolla CA 92093 USA
| | - Derek Gagnon
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive La Jolla CA 92093 USA
| | - Julian Esselborn
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive La Jolla CA 92093 USA
| | - R. David Britt
- Department of Chemistry University of California, Davis 1 Shields Avenue Davis CA 95616 USA
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive La Jolla CA 92093 USA
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16
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Han K, Bailey JB, Zhang L, Tezcan FA. Anisotropic Dynamics and Mechanics of Macromolecular Crystals Containing Lattice-Patterned Polymer Networks. J Am Chem Soc 2020; 142:19402-19410. [PMID: 33124805 DOI: 10.1021/jacs.0c10065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mechanical and functional properties of many crystalline materials depend on cooperative changes in lattice arrangements in response to external perturbations. However, the flexibility and adaptiveness of crystalline materials are limited. Additionally, the bottom-up, molecular-level design of crystals with desired dynamic and mechanical properties at the macroscopic level remains a considerable challenge. To address these challenges, we had previously integrated mesoporous, cubic ferritin crystals with hydrogel networks, resulting in hybrid materials (polymer-integrated crystals or PIX) which could undergo dramatic structural changes while maintaining crystalline periodicity and display efficient self-healing. The dynamics and mechanics of these ferritin-PIX were devoid of directionality, which is an important attribute of many molecular and macroscopic materials/devices. In this study, we report that such directionality can be achieved through the use of ferritin crystals with anisotropic symmetries (rhombohedral or trigonal), which enable the templated formation of patterned hydrogel networks in crystallo. The resulting PIX expand and contract anisotropically without losing crystallinity, undergo prompt bending motions in response to stimuli, and self-heal efficiently, capturing some of the essential features of sophisticated biological devices like skeletal muscles.
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Affiliation(s)
- Kenneth Han
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Ling Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.,Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
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17
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Abstract
We recently introduced protein-metal-organic frameworks (protein-MOFs) as chemically designed protein crystals, composed of ferritin nodes that predictably assemble into 3D lattices upon coordination of various metal ions and ditopic, hydroxamate-based linkers. Owing to their unique tripartite construction, protein-MOFs possess extremely sparse lattice connectivity, suggesting that they might display unusual thermomechanical properties. Leveraging the synthetic modularity of ferritin-MOFs, we investigated the temperature-dependent structural dynamics of six distinct frameworks. Our results show that the thermostabilities of ferritin-MOFs can be tuned through the metal component or the presence of crowding agents. Our studies also reveal a framework that undergoes a reversible and isotropic first-order phase transition near-room temperature, corresponding to a 4% volumetric change within 1 °C and a hysteresis window of ∼10 °C. This highly cooperative crystal-to-crystal transformation, which stems from the soft crystallinity of ferritin-MOFs, illustrates the advantage of modular construction strategies in discovering tunable-and unpredictable-material properties.
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Affiliation(s)
- Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.,Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
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18
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Kakkis A, Gagnon D, Esselborn J, Britt RD, Tezcan FA. Metal-Templated Design of Chemically Switchable Protein Assemblies with High-Affinity Coordination Sites. Angew Chem Int Ed Engl 2020; 59:21940-21944. [PMID: 32830423 DOI: 10.1002/anie.202009226] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/13/2020] [Indexed: 11/09/2022]
Abstract
To mimic a hypothetical pathway for protein evolution, we previously tailored a monomeric protein (cyt cb562 ) for metal-mediated self-assembly, followed by re-design of the resulting oligomers for enhanced stability and metal-based functions. We show that a single hydrophobic mutation on the cyt cb562 surface drastically alters the outcome of metal-directed oligomerization to yield a new trimeric architecture, (TriCyt1)3. This nascent trimer was redesigned into second and third-generation variants (TriCyt2)3 and (TriCyt3)3 with increased structural stability and preorganization for metal coordination. The three TriCyt variants combined furnish a unique platform to 1) provide tunable coupling between protein quaternary structure and metal coordination, 2) enable the construction of metal/pH-switchable protein oligomerization motifs, and 3) generate a robust metal coordination site that can coordinate all mid-to-late first-row transition-metal ions with high affinity.
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Affiliation(s)
- Albert Kakkis
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Derek Gagnon
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Julian Esselborn
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - R David Britt
- Department of Chemistry, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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19
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Bentz KC, Gnanasekaran K, Bailey JB, Ayala S, Tezcan FA, Gianneschi NC, Cohen SM. Inside polyMOFs: layered structures in polymer-based metal-organic frameworks. Chem Sci 2020; 11:10523-10528. [PMID: 34123187 PMCID: PMC8162296 DOI: 10.1039/d0sc03651j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In this report, we explore the internal structural features of polyMOFs consisting of equal mass ratios of metal-coordinating poly(benzenedicarboxylic acid) blocks and non-coordinating poly(ethylene glycol) (PEG) blocks. The studies reveal alternating lamellae of metal-rich, crystalline regions and metal-deficient non-crystalline polymer, which span the length of hundreds of nanometers. Polymers consisting of random PEG blocks, PEG end-blocks, or non-coordinating poly(cyclooctadiene) (COD) show similar alternation of metal-rich and metal-deficient regions, indicating a universal self-assembly mechanism. A variety of techniques were employed to interrogate the internal structure of the polyMOFs, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and small-angle synchrotron X-ray scattering (SAXS). Independent of the copolymer architecture or composition, the internal structure of the polyMOF crystals showed similar lamellar self-assembly at single-nanometer length scales. In this report, we explore the internal structural features of polyMOFs consisting of equal mass ratios of metal-coordinating poly(benzenedicarboxylic acid) blocks and non-coordinating poly(ethylene glycol) (PEG) blocks.![]()
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Affiliation(s)
- Kyle C Bentz
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093-0358 USA
| | - Karthikeyan Gnanasekaran
- Departments of Chemistry, Materials Science & Engineering, Biomedical Engineering, Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University Evanston Illinois 60208 USA
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093-0358 USA
| | - Sergio Ayala
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093-0358 USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093-0358 USA
| | - Nathan C Gianneschi
- Departments of Chemistry, Materials Science & Engineering, Biomedical Engineering, Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University Evanston Illinois 60208 USA
| | - Seth M Cohen
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093-0358 USA
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20
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Abstract
Nitrogenase is the only enzyme capable of reducing N2 to NH3. This challenging reaction requires the coordinated transfer of multiple electrons from the reductase, Fe-protein, to the catalytic component, MoFe-protein, in an ATP-dependent fashion. In the last two decades, there have been significant advances in our understanding of how nitrogenase orchestrates electron transfer (ET) from the Fe-protein to the catalytic site of MoFe-protein and how energy from ATP hydrolysis transduces the ET processes. In this review, we summarize these advances, with focus on the structural and thermodynamic redox properties of nitrogenase component proteins and their complexes, as well as on new insights regarding the mechanism of ET reactions during catalysis and how they are coupled to ATP hydrolysis. We also discuss recently developed chemical, photochemical, and electrochemical methods for uncoupling substrate reduction from ATP hydrolysis, which may provide new avenues for studying the catalytic mechanism of nitrogenase.
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Affiliation(s)
- Hannah L Rutledge
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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21
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Chiong JA, Zhu J, Bailey JB, Kalaj M, Subramanian RH, Xu W, Cohen SM, Tezcan FA. An Exceptionally Stable Metal–Organic Framework Constructed from Chelate-Based Metal–Organic Polyhedra. J Am Chem Soc 2020; 142:6907-6912. [DOI: 10.1021/jacs.0c01626] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jerika A. Chiong
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jie Zhu
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jake B. Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Mark Kalaj
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Rohit H. Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Wenqian Xu
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Seth M. Cohen
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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22
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Abstract
Molybdenum nitrogenase catalyzes the reduction of dinitrogen into ammonia, which requires the coordinated transfer of eight electrons to the active site cofactor (FeMoco) through the intermediacy of an [8Fe-7S] cluster (P-cluster), both housed in the molybdenum-iron protein (MoFeP). Previous studies on MoFeP from two different organisms, Azotobacter vinelandii ( Av) and Gluconacetobacter diazotrophicus ( Gd), have established that the P-cluster is conformationally flexible and can undergo substantial structural changes upon two-electron oxidation to the POX state, whereby a backbone amidate and an oxygenic residue (Ser or Tyr) ligate to two of the cluster's Fe centers. This redox-dependent change in coordination has been implicated in the conformationally gated electron transfer in nitrogenase. Here, we have investigated the role of the oxygenic ligand in Av MoFeP, which natively contains a Ser ligand (βSer188) to the P-cluster. Three variants were generated in which (1) the oxygenic ligand was eliminated (βSer188Ala), (2) the P-cluster environment was converted to the one in Gd MoFeP (βPhe99Tyr/βSer188Ala), and (3) two oxygenic ligands were simultaneously included (βPhe99Tyr). Our studies have revealed that the P-cluster can become compositionally labile upon oxidation and reversibly lose one or two Fe centers in the absence of the oxygenic ligand, while still retaining wild-type-like dinitrogen reduction activity. Our findings also suggest that Av and Gd MoFePs evolved with specific preferences for Ser and Tyr ligands, respectively, and that the structural control of these ligands must extend beyond the primary and secondary coordination spheres of the P-cluster. The P-cluster adds to the increasing number of examples of inherently labile Fe-S clusters whose compositional instability may be an obligatory feature to enable redox-linked conformational changes to facilitate multielectron redox reactions.
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Affiliation(s)
- Hannah L Rutledge
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
| | - Jonathan Rittle
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
| | - Laura M Williamson
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
| | - Wanqing A Xu
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
| | - Derek M Gagnon
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0356 , United States
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23
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Rittle J, Field MJ, Green MT, Tezcan FA. An efficient, step-economical strategy for the design of functional metalloproteins. Nat Chem 2019; 11:434-441. [PMID: 30778140 PMCID: PMC6483823 DOI: 10.1038/s41557-019-0218-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/11/2019] [Indexed: 01/31/2023]
Abstract
The bottom-up design and construction of functional metalloproteins remains a formidable task in biomolecular design. Although numerous strategies have been used to create new metalloproteins, pre-existing knowledge of the tertiary and quaternary protein structure is often required to generate suitable platforms for robust metal coordination and activity. Here we report an alternative and easily implemented approach (metal active sites by covalent tethering or MASCoT) in which folded protein building blocks are linked by a single disulfide bond to create diverse metal coordination environments within evolutionarily naive protein-protein interfaces. Metalloproteins generated using this strategy uniformly bind a wide array of first-row transition metal ions (MnII, FeII, CoII, NiII, CuII, ZnII and vanadyl) with physiologically relevant thermodynamic affinities (dissociation constants ranging from 700 nM for MnII to 50 fM for CuII). MASCoT readily affords coordinatively unsaturated metal centres-including a penta-His-coordinated non-haem Fe site-and well-defined binding pockets that can accommodate modifications and enable coordination of exogenous ligands such as nitric oxide to the interfacial metal centre.
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Affiliation(s)
- Jonathan Rittle
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Mackenzie J Field
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Michael T Green
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
- Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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24
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Abstract
Nature puts to use only a small fraction of metal ions in the periodic table. Yet, when incorporated into protein scaffolds, this limited set of metal ions carry out innumerable cellular functions and execute essential biochemical transformations such as photochemical H2O oxidation, O2 or CO2 reduction, and N2 fixation, highlighting the outsized importance of metalloproteins in biology. Not surprisingly, elucidating the intricate interplay between metal ions and protein structures has been the focus of extensive structural and mechanistic scrutiny over the last several decades. As a result of such top-down efforts, we have gained a reasonably detailed understanding of how metal ions shape protein structures and how protein structures in turn influence metal reactivity. It is fair to say that we now have some idea-and in some cases, a good idea-about how most known metalloproteins function and we possess enough insight to quickly assess the modus operandi of newly discovered ones. However, translating this knowledge into an ability to construct functional metalloproteins from scratch represents a challenge at a whole different level: it is one thing to know how an automobile works; it is another to build one. In our quest to build new metalloproteins, we have taken an original approach in which folded, monomeric proteins are used as ligands or synthons for building supramolecular complexes through metal-mediated self-assembly (MDPSA, Metal-Directed Protein Self-Assembly). The interfaces in the resulting protein superstructures are subsequently tailored with covalent, noncovalent, or additional metal-coordination interactions for stabilization and incorporation of new functionalities (MeTIR, Metal Templated Interface Redesign). In an earlier Account, we had described the proof-of-principle studies for MDPSA and MeTIR, using a four-helix bundle, heme protein cytochrome cb562 (cyt cb562), as a model building block. By the end of those studies, we were able to demonstrate that a tetrameric, Zn-directed cyt cb562 complex (Zn4:M14) could be stabilized through computationally prescribed noncovalent interactions inserted into the nascent protein-protein interfaces. In this Account, we first describe the rationale and motivation for our particular metalloprotein engineering strategy and a brief summary of our earlier work. We then describe the next steps in the "evolution" of bioinorganic complexity on the Zn4:M14 scaffold, namely, (a) the generation of a self-standing protein assembly that can stably and selectively bind metal ions, (b) the creation of reactive metal centers within the protein assembly, and (c) the coupling of metal coordination and reactivity to external stimuli through allosteric effects.
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Affiliation(s)
- Lewis A. Churchfield
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356, United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356, United States
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25
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Subramanian R, Smith SJ, Alberstein RG, Bailey JB, Zhang L, Cardone G, Suominen L, Chami M, Stahlberg H, Baker TS, Tezcan FA. Self-Assembly of a Designed Nucleoprotein Architecture through Multimodal Interactions. ACS Cent Sci 2018; 4:1578-1586. [PMID: 30555911 PMCID: PMC6276041 DOI: 10.1021/acscentsci.8b00745] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Indexed: 06/09/2023]
Abstract
The co-self-assembly of proteins and nucleic acids (NAs) produces complex biomolecular machines (e.g., ribosomes and telomerases) that represent some of the most daunting targets for biomolecular design. Despite significant advances in protein and DNA or RNA nanotechnology, the construction of artificial nucleoprotein complexes has largely been limited to cases that rely on the NA-mediated spatial organization of protein units, rather than a cooperative interplay between protein- and NA-mediated interactions that typify natural nucleoprotein assemblies. We report here a structurally well-defined synthetic nucleoprotein assembly that forms through the synergy of three types of intermolecular interactions: Watson-Crick base pairing, NA-protein interactions, and protein-metal coordination. The fine thermodynamic balance between these interactions enables the formation of a crystalline architecture under highly specific conditions.
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Affiliation(s)
- Rohit
H. Subramanian
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Sarah J. Smith
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Robert G. Alberstein
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Jake B. Bailey
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Ling Zhang
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Giovanni Cardone
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Lauri Suominen
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Mohamed Chami
- C−CINA,
Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Henning Stahlberg
- C−CINA,
Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Timothy S. Baker
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
- Division
of Biological Sciences, University of California,
San Diego, La Jolla, California 92093, United States
| | - F. Akif Tezcan
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
- Materials
Science and Engineering, University of California,
San Diego, La Jolla, California 92093, United States
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26
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Churchfield LA, Alberstein RG, Williamson LM, Tezcan FA. Determining the Structural and Energetic Basis of Allostery in a De Novo Designed Metalloprotein Assembly. J Am Chem Soc 2018; 140:10043-10053. [PMID: 29996654 PMCID: PMC6085756 DOI: 10.1021/jacs.8b05812] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite significant progress in protein design, the construction of protein assemblies that display complex functions (e.g., catalysis or allostery) remains a significant challenge. We recently reported the de novo construction of an allosteric supramolecular protein assembly (Zn-C38/C81/C96R14) in which the dissociation and binding of ZnII ions were coupled over a distance of 15 Å to the selective hydrolytic breakage and formation of a single disulfide bond. Zn-C38/C81/C96R14 was constructed by ZnII-templated assembly of a monomeric protein (R1, a derivative of cytochrome cb562) into a tetramer, followed by progressive incorporation of noncovalent and disulfide bonding interactions into the protein-protein interfaces to create a strained quaternary architecture. The interfacial strain thus built allowed mechanical coupling between the binding/dissociation of ZnII and formation/hydrolysis of a single disulfide bond (C38-C38) out of a possible six. While the earlier study provided structural evidence for the two end-states of allosteric coupling, the energetic basis for allosteric coupling and the minimal structural requirements for building this allosteric system were not understood. Toward this end, we have characterized the structures and Zn-binding properties of two related protein constructs (C38/C96R1 and C38R1) which also possess C38-C38 disulfide bonds. In addition, we have carried out extensive molecular dynamics simulations of C38/C81/C96R14 to understand the energetic basis for the selective cleavage of the C38-C38 disulfide bond upon ZnII dissociation. Our analyses reveal that the local interfacial environment around the C38-C38 bond is key to its selective cleavage, but this cleavage is only possible within the context of a stable quaternary architecture which enables structural coupling between ZnII coordination and the protein-protein interfaces.
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Affiliation(s)
- Lewis A. Churchfield
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356 United States
| | - Robert G. Alberstein
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356 United States
| | - Laura M. Williamson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356 United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356 United States
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27
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Zhang L, Bailey JB, Subramanian RH, Groisman A, Tezcan FA. Author Correction: Hyperexpandable, self-healing macromolecular crystals with integrated polymer networks. Nature 2018; 560:E31. [PMID: 29973728 DOI: 10.1038/s41586-018-0283-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Change history: In this Letter, Alexander Groisman should have been listed as an author. This error has been corrected online.
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Affiliation(s)
- Ling Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Rohit H Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Alexander Groisman
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. .,Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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28
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Zhang L, Bailey JB, Subramanian RH, Groisman A, Tezcan FA. Hyperexpandable, self-healing macromolecular crystals with integrated polymer networks. Nature 2018; 557:86-91. [PMID: 29720635 PMCID: PMC6334653 DOI: 10.1038/s41586-018-0057-7] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 03/12/2018] [Indexed: 11/08/2022]
Abstract
The formation of condensed matter typically involves a trade-off between structural order and flexibility. As the extent and directionality of interactions between atomic or molecular components increase, materials generally become more ordered but less compliant, and vice versa. Nevertheless, high levels of structural order and flexibility are not necessarily mutually exclusive; there are many biological (such as microtubules1,2, flagella 3 , viruses4,5) and synthetic assemblies (for example, dynamic molecular crystals6-9 and frameworks10-13) that can undergo considerable structural transformations without losing their crystalline order and that have remarkable mechanical properties8,14,15 that are useful in diverse applications, such as selective sorption 16 , separation 17 , sensing 18 and mechanoactuation 19 . However, the extent of structural changes and the elasticity of such flexible crystals are constrained by the necessity to maintain a continuous network of bonding interactions between the constituents of the lattice. Consequently, even the most dynamic porous materials tend to be brittle and isolated as microcrystalline powders 14 , whereas flexible organic or inorganic molecular crystals cannot expand without fracturing. Owing to their rigidity, crystalline materials rarely display self-healing behaviour 20 . Here we report that macromolecular ferritin crystals with integrated hydrogel polymers can isotropically expand to 180 per cent of their original dimensions and more than 500 per cent of their original volume while retaining periodic order and faceted Wulff morphologies. Even after the separation of neighbouring ferritin molecules by 50 ångströms upon lattice expansion, specific molecular contacts between them can be reformed upon lattice contraction, resulting in the recovery of atomic-level periodicity and the highest-resolution ferritin structure reported so far. Dynamic bonding interactions between the hydrogel network and the ferritin molecules endow the crystals with the ability to resist fragmentation and self-heal efficiently, whereas the chemical tailorability of the ferritin molecules enables the creation of chemically and mechanically differentiated domains within single crystals.
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Affiliation(s)
- Ling Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Rohit H Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Alexander Groisman
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
- Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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29
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Alberstein R, Suzuki Y, Paesani F, Tezcan FA. Engineering the entropy-driven free-energy landscape of a dynamic nanoporous protein assembly. Nat Chem 2018; 10:732-739. [PMID: 29713036 DOI: 10.1038/s41557-018-0053-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/29/2018] [Indexed: 12/27/2022]
Abstract
De novo design and construction of stimuli-responsive protein assemblies that predictably switch between discrete conformational states remains an essential but highly challenging goal in biomolecular design. We previously reported synthetic, two-dimensional protein lattices self-assembled via disulfide bonding interactions, which endows them with a unique capacity to undergo coherent conformational changes without losing crystalline order. Here, we carried out all-atom molecular dynamics simulations to map the free-energy landscape of these lattices, validated this landscape through extensive structural characterization by electron microscopy and established that it is predominantly governed by solvent reorganization entropy. Subsequent redesign of the protein surface with conditionally repulsive electrostatic interactions enabled us to predictably perturb the free-energy landscape and obtain a new protein lattice whose conformational dynamics can be chemically and mechanically toggled between three different states with varying porosities and molecular densities.
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Affiliation(s)
- Robert Alberstein
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Yuta Suzuki
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. .,Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. .,Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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30
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31
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Song WJ, Yu J, Tezcan FA. Importance of Scaffold Flexibility/Rigidity in the Design and Directed Evolution of Artificial Metallo-β-lactamases. J Am Chem Soc 2017; 139:16772-16779. [PMID: 28992705 DOI: 10.1021/jacs.7b08981] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We describe the design and evolution of catalytic hydrolase activity on a supramolecular protein scaffold, Zn4:C96RIDC14, which was constructed from cytochrome cb562 building blocks via a metal-templating strategy. Previously, we reported that Zn4:C96RIDC14 could be tailored with tripodal (His/His/Glu), unsaturated Zn coordination motifs in its interfaces to generate a variant termed Zn8:A104AB34, which in turn displayed catalytic activity for the hydrolysis of activated esters and β-lactam antibiotics. Zn8:A104AB34 was subsequently subjected to directed evolution via an in vivo selection strategy, leading to a variant Zn8:A104/G57AB34 which displayed enzyme-like Michaelis-Menten behavior for ampicillin hydrolysis. A criterion for the evolutionary utility or designability of a new protein structure is its ability to accommodate different active sites. With this in mind, we examined whether Zn4:C96RIDC14 could be tailored with alternative Zn coordination sites that could similarly display evolvable catalytic activities. We report here a detailed structural and functional characterization of new variant Zn8:AB54, which houses similar, unsaturated Zn coordination sites to those in Zn8:A104/G57AB34, but in completely different microenvironments. Zn8:AB54 displays Michaelis-Menten behavior for ampicillin hydrolysis without any optimization. Yet, the subsequent directed evolution of Zn8:AB54 revealed limited catalytic improvement, which we ascribed to the local protein rigidity surrounding the Zn centers and the lack of evolvable loop structures nearby. The relaxation of local rigidity via the elimination of adjacent disulfide linkages led to a considerable structural transformation with a concomitant improvement in β-lactamase activity. Our findings reaffirm previous observations that the delicate balance between protein flexibility and stability is crucial for enzyme design and evolution.
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Affiliation(s)
- Woon Ju Song
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States.,Department of Chemistry, Seoul National University , Seoul 08826, Korea
| | - Jaeseung Yu
- Department of Chemistry, Seoul National University , Seoul 08826, Korea
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
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32
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Abstract
Previously, we adopted the construction principles of metal-organic frameworks (MOFs) to design a 3D crystalline protein lattice in which pseudospherical ferritin nodes decorated on their C3 symmetric vertices with Zn coordination sites were connected via a ditopic benzene-dihydroxamate linker. In this work, we have systematically varied both the metal ions presented at the vertices of the ferritin nodes (Zn(II), Ni(II), and Co(II)) and the synthetic dihydroxamate linkers, which yielded an expanded library of 15 ferritin-MOFs with the expected body-centered (cubic or tetragonal) lattice arrangements. Crystallographic and small-angle X-ray scattering (SAXS) analyses indicate that lattice symmetries and dimensions of ferritin-MOFs can be dictated by both the metal and linker components. SAXS measurements on bulk crystalline samples reveal that some ferritin-MOFs can adopt multiple lattice conformations, suggesting dynamic behavior. This work establishes that the self-assembly of ferritin-MOFs is highly robust and that the synthetic modularity that underlies the structural diversity of conventional MOFs can also be applied to the self-assembly of protein-based crystalline materials.
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Affiliation(s)
- Jake B Bailey
- Department of Chemistry and Biochemistry, University of California at San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Ling Zhang
- Department of Chemistry and Biochemistry, University of California at San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jerika A Chiong
- Department of Chemistry and Biochemistry, University of California at San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sunhyung Ahn
- Department of Chemistry and Biochemistry, University of California at San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California at San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
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33
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Chabolla SA, Machan CW, Yin J, Dellamary EA, Sahu S, Gianneschi NC, Gilson MK, Tezcan FA, Kubiak CP. Bio-inspired CO 2 reduction by a rhenium tricarbonyl bipyridine-based catalyst appended to amino acids and peptidic platforms: incorporating proton relays and hydrogen-bonding functional groups. Faraday Discuss 2017; 198:279-300. [PMID: 28374024 PMCID: PMC5604230 DOI: 10.1039/c7fd00003k] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report a new approach to bio-inspired catalyst design. The molecular catalyst employed in these studies is based on the robust and selective Re(bpy)(CO)3Cl-type (bpy = 2,2'-bipyridine) homogeneous catalysts, which have been extensively studied for their ability to reduce CO2 electrochemically or photochemically in the presence of a photosensitizer. These catalysts can be highly active photocatalysts in their own right. In this work, the bipyridine ligand was modified with amino acids and synthetic peptides. These results build on earlier findings wherein the bipyridine ligand was functionalized with amide groups to promote dimer formation and CO2 reduction by an alternate bimolecular mechanism at lower overpotential (ca. 250 mV) than the more commonly observed unimolecular process. The bio-inspired catalysts were designed to allow for the incorporation of proton relays to support reduction of CO2 to CO and H2O. The coupling of amino acids tyrosine and phenylalanine led to the formation of two structurally similar Re catalyst/peptide catalysts for comparison of proton transport during catalysis. This article reports the synthesis and characterization of novel catalyst/peptide hybrids by molecular dynamics (MD simulations of structural dynamics), NMR studies of solution phase structures, and electrochemical studies to measure the activities of new bio-inspired catalysts in the reduction of CO2.
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Affiliation(s)
- S A Chabolla
- University of California, Department of Chemistry and Biochemistry, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA.
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34
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Churchfield LA, Medina-Morales A, Brodin JD, Perez A, Tezcan FA. De Novo Design of an Allosteric Metalloprotein Assembly with Strained Disulfide Bonds. J Am Chem Soc 2016; 138:13163-13166. [PMID: 27649076 DOI: 10.1021/jacs.6b08458] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A major goal in metalloprotein design is to build protein scaffolds from scratch that allow precise control over metal coordination. A particular challenge in this regard is the construction of allosteric systems in which metal coordination equilibria are coupled to other chemical events that take place elsewhere in the protein scaffold. We previously developed a metal-templated self-assembly strategy (MeTIR) to build supramolecular protein complexes with tailorable interfaces from monomeric building blocks. Here, using this strategy, we have incorporated multiple disulfide bonds into the interfaces of a Zn-templated cytochrome cb562 assembly in order to create mechanical strain on the quaternary structural level. Structural and biophysical analyses indicate that this strain leads to an allosteric system in which Zn2+ binding and dissociation are remotely coupled to the formation and breakage of a disulfide bond over a distance of >14 Å. The breakage of this strained bond upon Zn2+ dissociation occurs in the absence of any reductants, apparently through a hydrolytic mechanism that generates a sulfenic acid/thiol pair.
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Affiliation(s)
- Lewis A Churchfield
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
| | - Annette Medina-Morales
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
| | - Jeffrey D Brodin
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
| | - Alfredo Perez
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
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35
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Owens CP, Katz FEH, Carter CH, Oswald VF, Tezcan FA. Tyrosine-Coordinated P-Cluster in G. diazotrophicus Nitrogenase: Evidence for the Importance of O-Based Ligands in Conformationally Gated Electron Transfer. J Am Chem Soc 2016; 138:10124-7. [PMID: 27487256 DOI: 10.1021/jacs.6b06783] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The P-cluster is a unique iron-sulfur center that likely functions as a dynamic electron (e(-)) relay site between the Fe-protein and the catalytic FeMo-cofactor in nitrogenase. The P-cluster has been shown to undergo large conformational changes upon 2-e(-) oxidation which entail the coordination of two of the Fe centers to a Ser side chain and a backbone amide N, respectively. Yet, how and if this 2-e(-) oxidized state (P(OX)) is involved in catalysis by nitrogenase is not well established. Here, we present the crystal structures of reduced and oxidized MoFe-protein (MoFeP) from Gluconacetobacter diazotrophicus (Gd), which natively possesses an Ala residue in the position of the Ser ligand to the P-cluster. While reduced Gd-MoFeP is structurally identical to previously characterized counterparts around the FeMo-cofactor, oxidized Gd-MoFeP features an unusual Tyr coordination to its P-cluster along with ligation by a backbone amide nitrogen. EPR analysis of the oxidized Gd-MoFeP P-cluster confirmed that it is a 2-e(-) oxidized, integer-spin species. Importantly, we have found that the sequence positions corresponding to the Ser and Tyr ligands are almost completely covariant among Group I nitrogenases. These findings strongly support the possibility that the P(OX) state is functionally relevant in nitrogenase catalysis and that a hard, O-based anionic ligand serves to stabilize this state in a switchable fashion.
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Affiliation(s)
- Cedric P Owens
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0356, United States
| | - Faith E H Katz
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0356, United States
| | - Cole H Carter
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0356, United States
| | - Victoria F Oswald
- Department of Chemistry, University of California , Irvine, 1102 Natural Science II, Irvine, California 92697, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0356, United States
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36
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Suzuki Y, Cardone G, Restrepo D, Zavattieri PD, Baker TS, Tezcan FA. Self-assembly of coherently dynamic, auxetic, two-dimensional protein crystals. Nature 2016; 533:369-73. [PMID: 27135928 PMCID: PMC4991361 DOI: 10.1038/nature17633] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/01/2016] [Indexed: 12/25/2022]
Abstract
Two-dimensional (2D) crystalline materials possess unique structural, mechanical and electronic properties that make them highly attractive in many applications. Although there have been advances in preparing 2D materials that consist of one or a few atomic or molecular layers, bottom-up assembly of 2D crystalline materials remains a challenge and an active area of development. More challenging is the design of dynamic 2D lattices that can undergo large-scale motions without loss of crystallinity. Dynamic behaviour in porous three-dimensional (3D) crystalline solids has been exploited for stimuli-responsive functions and adaptive behaviour. As in such 3D materials, integrating flexibility and adaptiveness into crystalline 2D lattices would greatly broaden the functional scope of 2D materials. Here we report the self-assembly of unsupported, 2D protein lattices with precise spatial arrangements and patterns using a readily accessible design strategy. Three single- or double-point mutants of the C4-symmetric protein RhuA were designed to assemble via different modes of intermolecular interactions (single-disulfide, double-disulfide and metal-coordination) into crystalline 2D arrays. Owing to the flexibility of the single-disulfide interactions, the lattices of one of the variants ((C98)RhuA) are essentially defect-free and undergo substantial, but fully correlated, changes in molecular arrangement, yielding coherently dynamic 2D molecular lattices. (C98)RhuA lattices display a Poisson's ratio of -1-the lowest thermodynamically possible value for an isotropic material-making them auxetic.
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Affiliation(s)
- Yuta Suzuki
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Giovanni Cardone
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - David Restrepo
- School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907-2051, USA
| | - Pablo D. Zavattieri
- School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907-2051, USA
| | - Timothy S. Baker
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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37
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Smith SJ, Radford RJ, Subramanian RH, Barnett BR, Figueroa JS, Tezcan FA. Tunable Helicity, Stability and DNA-Binding Properties of Short Peptides with Hybrid Metal Coordination Motifs. Chem Sci 2016; 7:5453-5461. [PMID: 27800151 PMCID: PMC5085262 DOI: 10.1039/c6sc00826g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Given the prevalent role of α-helical motifs on protein surfaces in mediating protein-protein and protein-DNA interactions, there have been significant efforts to develop strategies to induce α-helicity in short, unstructured peptides to interrogate such interactions. Toward this goal, we have recently introduced hybrid metal coordination motifs (HCMs). HCMs combine a natural metal-binding amino acid side chain with a synthetic chelating group that are appropriately positioned in a peptide sequence to stabilize an α-helical conformation upon metal coordination. Here, we present a series of short peptides modified with HCMs consisting of a His and a phenanthroline group at i and i+7 positions that can induce α-helicity in a metal-tunable fashion as well as direct the formation of discrete dimeric architectures for recognition of biological targets. We show that the induction of α-helicity can be further modulated by secondary sphere interactions between amino acids at the i+4 position and the HCM. A frequently cited drawback of the use of peptides as therapeutics is their propensity to be quickly digested by proteases; here, we observe an enhancement of up to ∼100-fold in the half-lifes of the metal-bound HCM-peptides in the presence of trypsin. Finally, we show that an HCM-bearing peptide sequence, which contains the DNA-recognition domain of a bZIP protein but is devoid of the obligate dimerization domain, can dimerize with the proper geometry and in an α-helical conformation to bind a cognate DNA sequence with high affinities (Kd≥ 65 nM), again in a metal-tunable manner.
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Affiliation(s)
- Sarah J Smith
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
| | - Robert J Radford
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
| | - Rohit H Subramanian
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
| | - Brandon R Barnett
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
| | - Joshua S Figueroa
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Mia, USA
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38
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Abstract
Owing to their central roles in cellular signaling, construction, and biochemistry, protein-protein interactions (PPIs) and protein self-assembly have become a major focus of molecular design and synthetic biology. In order to circumvent the complexity of constructing extensive noncovalent interfaces, which are typically involved in natural PPIs and protein self-assembly, we have developed two design strategies, metal-directed protein self-assembly (MDPSA) and metal-templated interface redesign (MeTIR). These strategies, inspired by both the proposed evolutionary roles of metals and their prevalence in natural PPIs, take advantage of the favorable properties of metal coordination (bonding strength, directionality, and reversibility) to guide protein self-assembly with minimal design and engineering. Using a small, monomeric protein (cytochrome cb562) as a model building block, we employed MDPSA and MeTIR to create a diverse array of functional supramolecular architectures which range from structurally tunable oligomers to metalloprotein complexes that can properly self-assemble in living cells into novel metalloenzymes. The design principles and strategies outlined herein should be readily applicable to other protein systems with the goal of creating new PPIs and protein assemblies with structures and functions not yet produced by natural evolution.
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Affiliation(s)
- J B Bailey
- University of California, San Diego, La Jolla, CA, United States
| | - R H Subramanian
- University of California, San Diego, La Jolla, CA, United States
| | - L A Churchfield
- University of California, San Diego, La Jolla, CA, United States
| | - F A Tezcan
- University of California, San Diego, La Jolla, CA, United States.
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39
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Abstract
Nitrogenase is the only enzyme that can convert atmospheric dinitrogen (N2) into biologically usable ammonia (NH3). To achieve this multielectron redox process, the nitrogenase component proteins, MoFe-protein (MoFeP) and Fe-protein (FeP), repeatedly associate and dissociate in an ATP-dependent manner, where one electron is transferred from FeP to MoFeP per association. Here, we provide experimental evidence that encounter complexes between FeP and MoFeP play a functional role in nitrogenase catalysis. The encounter complexes are stabilized by electrostatic interactions involving a positively charged patch on the β-subunit of MoFeP. Three single mutations (βAsn399Glu, βLys400Glu, and βArg401Glu) in this patch were generated in Azotobacter vinelandii MoFeP. All of the resulting variants displayed decreases in specific catalytic activity, with the βK400E mutation showing the largest effect. As simulated by the Thorneley-Lowe kinetic scheme, this single mutation lowered the rate constant for FeP-MoFeP association 5-fold. We also found that the βK400E mutation did not affect the coupling of ATP hydrolysis with electron transfer (ET) between FeP and MoFeP. These data suggest a mechanism where FeP initially forms encounter complexes on the MoFeP β-subunit surface en route to the ATP-activated, ET-competent complex over the αβ-interface.
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Affiliation(s)
- Cedric P. Owens
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92039, United States
| | - Faith E. H. Katz
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92039, United States
| | - Cole H. Carter
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92039, United States
| | - Maria A. Luca
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92039, United States
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92039, United States
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40
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Sontz PA, Bailey JB, Ahn S, Tezcan FA. A Metal Organic Framework with Spherical Protein Nodes: Rational Chemical Design of 3D Protein Crystals. J Am Chem Soc 2015; 137:11598-601. [PMID: 26305584 DOI: 10.1021/jacs.5b07463] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We describe here the construction of a three-dimensional, porous, crystalline framework formed by spherical protein nodes that assemble into a prescribed lattice arrangement through metal-organic linker-directed interactions. The octahedral iron storage enzyme, ferritin, was engineered in its C3 symmetric pores with tripodal Zn coordination sites. Dynamic light scattering and crystallographic studies established that this Zn-ferritin construct could robustly self-assemble into the desired bcc-type crystals upon coordination of a ditopic linker bearing hydroxamic acid functional groups. This system represents the first example of a ternary protein-metal-organic crystalline framework whose formation is fully dependent on each of its three components.
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Affiliation(s)
- Pamela A Sontz
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jake B Bailey
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sunhyung Ahn
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
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41
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Brodin JD, Smith SJ, Carr JR, Tezcan FA. Designed, Helical Protein Nanotubes with Variable Diameters from a Single Building Block. J Am Chem Soc 2015; 137:10468-71. [PMID: 26256820 DOI: 10.1021/jacs.5b05755] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Due to their structural and mechanical properties, 1D helical protein assemblies represent highly attractive design targets for biomolecular engineering and protein design. Here we present a designed, tetrameric protein building block, Zn8R4, which assembles via Zn coordination interactions into a series of crystalline, helical nanotubes whose widths can be controlled by solution conditions. X-ray crystallography and transmission electron microscopy (TEM) measurements indicate that all classes of protein nanotubes are constructed through the same 2D arrangement of Zn8R4 tetramers held together by Zn coordination. The mechanical properties of these nanotubes are correlated with their widths. All Zn8R4 nanotubes are found to be highly flexible despite possessing crystalline order, owing to their minimal interbuilding-block interactions mediated solely by metal coordination.
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Affiliation(s)
- Jeffrey D Brodin
- Department of Chemistry & Biochemistry, UCSD , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sarah J Smith
- Department of Chemistry & Biochemistry, UCSD , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jessica R Carr
- Department of Chemistry & Biochemistry, UCSD , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - F Akif Tezcan
- Department of Chemistry & Biochemistry, UCSD , 9500 Gilman Drive, La Jolla, California 92093, United States
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42
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Abstract
The generation of new enzymatic activities has mainly relied on repurposing the interiors of preexisting protein folds because of the challenge in designing functional, three-dimensional protein structures from first principles. Here we report an artificial metallo-β-lactamase, constructed via the self-assembly of a structurally and functionally unrelated, monomeric redox protein into a tetrameric assembly that possesses catalytic zinc sites in its interfaces. The designed metallo-β-lactamase is functional in the Escherichia coli periplasm and enables the bacteria to survive treatment with ampicillin. In vivo screening of libraries has yielded a variant that displays a catalytic proficiency [(k(cat)/K(m))/k(uncat)] for ampicillin hydrolysis of 2.3 × 10(6) and features the emergence of a highly mobile loop near the active site, a key component of natural β-lactamases to enable substrate interactions.
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Affiliation(s)
- Woon Ju Song
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0356, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0356, USA.
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43
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Abstract
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The
roles of ATP hydrolysis in electron-transfer (ET) reactions
of the nitrogenase catalytic cycle remain obscure. Here, we present
a new structure of a nitrogenase complex crystallized with MgADP and
MgAMPPCP, an ATP analogue. In this structure the two nucleotides are
bound asymmetrically by the Fe-protein subunits connected to the two
different MoFe-protein subunits. This binding mode suggests that ATP
hydrolysis and phosphate release may proceed by a stepwise mechanism.
Through the associated Fe-protein conformational changes, a stepwise
mechanism is anticipated to prolong the lifetime of the Fe-protein-MoFe-protein
complex and, in turn, could orchestrate the sequence of intracomplex
ET required for substrate reduction.
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Affiliation(s)
- F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0356, United States
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44
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Machan CW, Chabolla SA, Yin J, Gilson MK, Tezcan FA, Kubiak CP. Supramolecular Assembly Promotes the Electrocatalytic Reduction of Carbon Dioxide by Re(I) Bipyridine Catalysts at a Lower Overpotential. J Am Chem Soc 2014; 136:14598-607. [DOI: 10.1021/ja5085282] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Charles W. Machan
- Department
of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - Steven A. Chabolla
- Department
of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - Jian Yin
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0736, United States
| | - Michael K. Gilson
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0736, United States
| | - F. Akif Tezcan
- Department
of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - Clifford P. Kubiak
- Department
of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
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45
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Chabolla SA, Dellamary EA, Machan CW, Tezcan FA, Kubiak CP. Combined steric and electronic effects of positional substitution on dimethyl-bipyridine rhenium(I)tricarbonyl electrocatalysts for the reduction of CO 2. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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Abstract
From the catalytic reactions that sustain the global oxygen, nitrogen, and carbon cycles to the stabilization of DNA processing proteins, transition metal ions and metallocofactors play key roles in biology. Although the exquisite interplay between metal ions and protein scaffolds has been studied extensively, the fact that the biological roles of the metals often stem from their placement in the interfaces between proteins and protein subunits is not always recognized. Interfacial metal ions stabilize permanent or transient protein-protein interactions, enable protein complexes involved in cellular signaling to adopt distinct conformations in response to environmental stimuli, and catalyze challenging chemical reactions that are uniquely performed by multisubunit protein complexes. This review provides a structural survey of transition metal ions and metallocofactors found in protein-protein interfaces, along with a series of selected examples that illustrate their diverse biological utility and significance.
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Affiliation(s)
- Woon Ju Song
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093; emails: , ,
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47
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Sontz PA, Song WJ, Tezcan FA. Interfacial metal coordination in engineered protein and peptide assemblies. Curr Opin Chem Biol 2014; 19:42-9. [PMID: 24780278 DOI: 10.1016/j.cbpa.2013.12.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 12/29/2022]
Abstract
Metal ions are frequently found in natural protein-protein interfaces, where they stabilize quaternary or supramolecular protein structures, mediate transient protein-protein interactions, and serve as catalytic centers. Paralleling these natural roles, coordination chemistry of metal ions is being increasingly utilized in creative ways toward engineering and controlling the assembly of functional supramolecular peptide and protein architectures. Here we provide a brief overview of this emerging branch of metalloprotein/peptide engineering and highlight a few select examples from the recent literature that best capture the diversity and future potential of approaches that are being developed.
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Affiliation(s)
- Pamela A Sontz
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, United States
| | - Woon Ju Song
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, United States.
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48
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Abstract
Many protein-protein interactions that play a central role in cellular processes involve α-helical domains. Consequently, there has been great interest in developing strategies for stabilizing short peptides in α-helical conformations toward the inhibition and interrogation of protein-protein interactions. Here, we show that tridentate Hybrid Coordination Motifs (HCMs), which consist of a natural (histidine, His) and an unnatural (8-hydroxyquinoline, Quin) metal binding functionality, can bind divalent metal ions with high affinity and thereby induce/stabilize an α-helical configuration in short peptide sequences. The Quin functionality is readily introduced onto peptide platforms both during or after solid-state peptide synthesis, demonstrating the preparative versatility of HCMs. A systematic study involving a series of HCM-bearing peptides has revealed the critical importance of the length of the linkage between the Quin moiety and the peptide backbone as well as the metal coordination geometry in determining the extent of α-helix induction. Through ZnII coordination or modification with ReI(Quin)(CO)3, the HCM-bearing peptides can be rendered luminescent in the visible region, thus showing that HCMs can be exploited to simultaneously introduce structure and functionality into short peptides.
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Affiliation(s)
- Sarah J Smith
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0356
| | - Kang Du
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0356
| | - Robert J Radford
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0356
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0356
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49
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Medina-Morales A, Perez A, Brodin JD, Tezcan FA. In vitro and cellular self-assembly of a Zn-binding protein cryptand via templated disulfide bonds. J Am Chem Soc 2013; 135:12013-22. [PMID: 23905754 DOI: 10.1021/ja405318d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Simultaneously strong and reversible through redox chemistry, disulfide bonds play a unique and often irreplaceable role in the formation of biological and synthetic assemblies. In an approach inspired by supramolecular chemistry, we report here that engineered noncovalent interactions on the surface of a monomeric protein can template its assembly into a unique cryptand-like protein complex ((C81/C96)RIDC14) by guiding the selective formation of multiple disulfide bonds across different interfaces. Owing to its highly interconnected framework, (C81/C96)RIDC14 is well preorganized for metal coordination in its interior, can support a large internal cavity surrounding the metal sites, and can withstand significant alterations in inner-sphere metal coordination. (C81/C96)RIDC14 self-assembles with high fidelity and yield in the periplasmic space of E. coli cells, where it can successfully compete for Zn(II) binding.
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Affiliation(s)
- Annette Medina-Morales
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356, USA
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50
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Huard DJE, Kane KM, Tezcan FA. Re-engineering protein interfaces yields copper-inducible ferritin cage assembly. Nat Chem Biol 2013; 9:169-76. [DOI: 10.1038/nchembio.1163] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 12/12/2012] [Indexed: 11/09/2022]
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