1
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Guseman AJ, González JJ, Yang D, Gronenborn AM. Cumulative asparagine to aspartate deamidation fails to perturb γD-crystallin structure and stability. Protein Sci 2024; 33:e5120. [PMID: 39022918 PMCID: PMC11255865 DOI: 10.1002/pro.5120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/05/2024] [Accepted: 07/07/2024] [Indexed: 07/20/2024]
Abstract
Deamidation frequently is invoked as an important driver of crystallin aggregation and cataract formation. Here, we characterized the structural and biophysical consequences of cumulative Asn to Asp changes in γD-crystallin. Using NMR spectroscopy, we demonstrate that N- or C-terminal domain-confined or fully Asn to Asp changed γD-crystallin exhibits essentially the same 1H-15N HSQC spectrum as the wild-type protein, implying that the overall structure is retained. Only a very small thermodynamic destabilization for the overall Asn to Asp γD-crystallin variants was noted by chaotropic unfolding, and assessment of the colloidal stability, by measuring diffusion interaction parameters, yielded no substantive differences in association propensities. Furthermore, using molecular dynamics simulations, no significant changes in dynamics for proteins with Asn to Asp or iso-Asp changes were detected. Our combined results demonstrate that substitution of all Asn by Asp residues, reflecting an extreme case of deamidation, did not affect the structure and biophysical properties of γD-crystallin. This suggests that these changes alone cannot be the major determinant in driving cataract formation.
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Affiliation(s)
- Alex J. Guseman
- Department of Structural BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Jeremy J. González
- Department of Structural BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Darian Yang
- Department of Structural BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Angela M. Gronenborn
- Department of Structural BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
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2
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Santhouse JR, Leung JMG, Chong LT, Horne WS. Effects of altered backbone composition on the folding kinetics and mechanism of an ultrafast-folding protein. Chem Sci 2024; 15:675-682. [PMID: 38179541 PMCID: PMC10763558 DOI: 10.1039/d3sc03976e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 12/02/2023] [Indexed: 01/06/2024] Open
Abstract
Sequence-encoded protein folding is a ubiquitous biological process that has been successfully engineered in a range of oligomeric molecules with artificial backbone chemical connectivity. A remarkable aspect of protein folding is the contrast between the rapid rates at which most sequences in nature fold and the vast number of conformational states possible in an unfolded chain with hundreds of rotatable bonds. Research efforts spanning several decades have sought to elucidate the fundamental chemical principles that dictate the speed and mechanism of natural protein folding. In contrast, little is known about how protein mimetic entities transition between an unfolded and folded state. Here, we report effects of altered backbone connectivity on the folding kinetics and mechanism of the B domain of Staphylococcal protein A (BdpA), an ultrafast-folding sequence. A combination of experimental biophysical analysis and atomistic molecular dynamics simulations performed on the prototype protein and several heterogeneous-backbone variants reveal the interplay among backbone flexibility, folding rates, and structural details of the transition state ensemble. Collectively, these findings suggest a significant degree of plasticity in the mechanisms that can give rise to ultrafast folding in the BdpA sequence and provide atomic level insights into how protein mimetic chains adopt an ordered folded state.
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Affiliation(s)
| | - Jeremy M G Leung
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Lillian T Chong
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - W Seth Horne
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
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3
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Coppa C, Bazzoli A, Barkhordari M, Contini A. Accelerated Molecular Dynamics for Peptide Folding: Benchmarking Different Combinations of Force Fields and Explicit Solvent Models. J Chem Inf Model 2023; 63:3030-3042. [PMID: 37163419 DOI: 10.1021/acs.jcim.3c00138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Accelerated molecular dynamics (aMD) protocols were assessed on predicting the secondary structure of eight peptides, of which two are helical, three are β-hairpins, and three are disordered. Protocols consisted of combinations of three force fields (ff99SB, ff14SB, ff19SB) and two explicit solvation models (TIP3P and OPC), and were evaluated in two independent aMD simulations, one starting from an extended conformation, the other starting from a misfolded conformation. The results of these analyses indicate that all three combinations performed well on helical peptides. As for β-hairpins, ff19SB performed well with both solvation methods, with a slight preference for the TIP3P solvation model, even though performance was dependent on both peptide sequence and initial conformation. The ff19SB/OPC combination had the best performance on intrinsically disordered peptides. In general, ff14SB/TIP3P suffered the strongest helical bias.
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Affiliation(s)
- Crescenzo Coppa
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano, Via Venezian, 21, 20133 Milano, Italy
| | - Andrea Bazzoli
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano, Via Venezian, 21, 20133 Milano, Italy
| | - Maral Barkhordari
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano, Via Venezian, 21, 20133 Milano, Italy
| | - Alessandro Contini
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano, Via Venezian, 21, 20133 Milano, Italy
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4
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Park J, Lee HS, Kim H, Choi JM. Conformational landscapes of artificial peptides predicted by various force fields: are we ready to simulate β-amino acids? Phys Chem Chem Phys 2023; 25:7466-7476. [PMID: 36848062 DOI: 10.1039/d2cp05998c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
With the introduction of artificial peptides as antimicrobial agents and organic catalysts, numerous efforts have been made to design foldamers with desirable structures and functions. Computational tools are a helpful proxy for revealing the dynamic structures at atomic resolution and understanding foldamer's complex structure-function relationships. However, the performance of conventional force fields in predicting the structures of artificial peptides has not been systematically evaluated. In this study, we critically assessed three popular force fields, AMBER ff14SB, CHARMM36m, and OPLS-AA/L, in predicting conformational propensities of a β-peptide foldamer at monomer and hexamer levels. Simulation results were compared to those obtained from quantum chemistry calculations and experimental data. We also utilised replica exchange molecular dynamics simulations to investigate the energy landscape of each force field and assess the similarities and differences between force fields. We compared different solvent systems in the AMBER ff14SB and CHARMM36m frameworks and confirmed the unanimous role of hydrogen bonds in shaping energy landscapes. We anticipate that our data will pave the way for further improvements to force fields and for understanding the role of solvents in peptide folding, crystallisation, and engineering.
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Affiliation(s)
- Jihye Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea.
| | - Hee-Seung Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea. .,Center for Multiscale Chiral Architectures, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hyungjun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea.
| | - Jeong-Mo Choi
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Geumjeong-gu, Busan 46241, Republic of Korea.
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5
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Calugi L, Sautariello G, Lenci E, Mattei ML, Coppa C, Cini N, Contini A, Trabocchi A. Identification of a short ACE2-derived stapled peptide targeting the SARS-CoV-2 spike protein. Eur J Med Chem 2023; 249:115118. [PMID: 36682293 PMCID: PMC9842534 DOI: 10.1016/j.ejmech.2023.115118] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 01/04/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023]
Abstract
The design and synthesis of a series of peptide derivatives based on a short ACE2 α-helix 1 epitope and subsequent [i - i+4] stapling of the secondary structure resulted in the identification of a 9-mer peptide capable to compete with recombinant ACE2 towards Spike RBD in the micromolar range. Specifically, SARS-CoV-2 Spike inhibitor screening based on colorimetric ELISA assay and structural studies by circular dichroism showed the ring-closing metathesis cyclization being capable to stabilize the helical structure of the 9-mer 34HEAEDLFYQ42 epitope better than the triazole stapling via click chemistry. MD simulations showed the stapled peptide being able not only to bind the Spike RBD, sterically interfering with ACE2, but also showing higher affinity to the target as compared to parent epitope.
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Affiliation(s)
- Lorenzo Calugi
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 13, 50019, Sesto Fiorentino, Florence, Italy
| | - Giulia Sautariello
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 13, 50019, Sesto Fiorentino, Florence, Italy
| | - Elena Lenci
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 13, 50019, Sesto Fiorentino, Florence, Italy
| | - Mauro Leucio Mattei
- General Laboratory, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
| | - Crescenzo Coppa
- Department of Pharmaceutical Sciences, University of Milan, Via Venezian 21, 20133, Milan, Italy
| | - Nicoletta Cini
- General Laboratory, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
| | - Alessandro Contini
- Department of Pharmaceutical Sciences, University of Milan, Via Venezian 21, 20133, Milan, Italy
| | - Andrea Trabocchi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019, Sesto Fiorentino, Florence, Italy.
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6
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Rao SR, Harmon TW, Heath SL, Wolfe JA, Santhouse JR, O'Brien GL, Distefano AN, Reinert ZE, Horne WS. Chemical Shifts of Artificial Monomers Used to Construct Heterogeneous-Backbone Protein Mimetics in Random Coil and Folded States. Pept Sci (Hoboken) 2023; 115:e24297. [PMID: 37397503 PMCID: PMC10312354 DOI: 10.1002/pep2.24297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/27/2022] [Indexed: 03/03/2024]
Abstract
The construction of protein-sized synthetic chains that blend natural amino acids with artificial monomers to create so-called heterogeneous-backbones is a powerful approach to generate complex folds and functions from bio-inspired agents. A variety of techniques from structural biology commonly used to study natural proteins have been adapted to investigate folding in these entities. In NMR characterization of proteins, proton chemical shift is a straightforward to acquire, information-rich metric that bears directly on a variety of properties related to folding. Leveraging chemical shift to gain insight into folding requires a set of reference chemical shift values corresponding to each building block type (i.e., the 20 canonical amino acids in the case of natural proteins) in a random coil state and knowledge of systematic changes in chemical shift associated with particular folded conformations. Although well documented for natural proteins, these issues remain unexplored in the context of protein mimetics. Here, we report random coil chemical shift values for a library of artificial amino acid monomers frequently used to construct heterogeneous-backbone protein analogues as well as a spectroscopic signature associated with one monomer class, β3-residues bearing proteinogenic side chains, adopting a helical folded conformation. Collectively, these results will facilitate the continued utilization of NMR for the study of structure and dynamics in protein-like artificial backbones.
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Affiliation(s)
- Shilpa R Rao
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Thomas W Harmon
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Shelby L Heath
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jacob A Wolfe
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | | | - Gregory L O'Brien
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Alexis N Distefano
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Zachary E Reinert
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - W Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
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7
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Cabalteja CC, Lin Q, Harmon TW, Rao SR, Di YP, Horne WS. Heterogeneous-Backbone Proteomimetic Analogues of Lasiocepsin, a Disulfide-Rich Antimicrobial Peptide with a Compact Tertiary Fold. ACS Chem Biol 2022; 17:987-997. [PMID: 35290019 PMCID: PMC9039985 DOI: 10.1021/acschembio.2c00138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The emergence of resistance to clinically used antibiotics by bacteria presents a significant problem in public health. Natural antimicrobial peptides (AMPs) are a valuable source of antibiotics that act by a mechanism less prone to the evolutionary development of resistance. In an effort to realize the promise of AMPs while overcoming limitations such as poor biostability, researchers have sought sequence-defined oligomers with artificial amide-based backbones that show membrane-disrupting functions similar to natural agents. Most of this precedent has focused on short peptidomimetic analogues of unstructured chains or secondary folds; however, the natural antimicrobial arsenal includes a number of small- and medium-sized proteins that act via an ordered tertiary structure. Generating proteomimetic analogues of these scaffolds poses a challenge due to the increased complexity of the target for mimicry. Here, we report the development of heterogeneous-backbone variants of lasiocepsin, a 27-residue disulfide-rich AMP found in bee venom that adopts a compact tertiary fold. Iterative cycles of design, synthesis, and biological evaluation yielded analogues of the natural domain with ∼30 to 40% artificial backbone content, comparable antibacterial activity, reduced host cell toxicity, and improved stability to proteolytic degradation. High-resolution structures determined for several variants by NMR provide insights into the interplay among backbone composition, tertiary fold, and biological properties. Collectively, the results reported here broaden the scope of protein functional mimicry by artificial backbone analogues of tertiary folding patterns and suggest protein backbone engineering as a means to tune protein function by exerting site-specific control over protein folded structure.
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Affiliation(s)
- Chino C. Cabalteja
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Qiao Lin
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Thomas W. Harmon
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Shilpa R. Rao
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Y. Peter Di
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - W. Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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8
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Yang D, Gronenborn AM, Chong LT. Development and Validation of Fluorinated, Aromatic Amino Acid Parameters for Use with the AMBER ff15ipq Protein Force Field. J Phys Chem A 2022; 126:2286-2297. [PMID: 35352936 PMCID: PMC9014858 DOI: 10.1021/acs.jpca.2c00255] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/15/2022] [Indexed: 12/27/2022]
Abstract
We developed force field parameters for fluorinated, aromatic amino acids enabling molecular dynamics (MD) simulations of fluorinated proteins. These parameters are tailored to the AMBER ff15ipq protein force field and enable the modeling of 4, 5, 6, and 7F-tryptophan, 3F- and 3,5F-tyrosine, and 4F- or 4-CF3-phenylalanine. The parameters include 181 unique atomic charges derived using the implicitly polarized charge (IPolQ) scheme in the presence of SPC/Eb explicit water molecules and 9 unique bond, angle, or torsion terms. Our simulations of benchmark peptides and proteins maintain expected conformational propensities on the μs time scale. In addition, we have developed an open-source Python program to calculate fluorine relaxation rates from MD simulations. The extracted relaxation rates from protein simulations are in good agreement with experimental values determined by 19F NMR. Collectively, our results illustrate the power and robustness of the IPolQ lineage of force fields for modeling the structure and dynamics of fluorine-containing proteins at the atomic level.
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Affiliation(s)
- Darian
T. Yang
- Molecular
Biophysics and Structural Biology Graduate Program, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, Pennsylvania 15260, United States
- Department
of Structural Biology, University of Pittsburgh
School of Medicine, Pittsburgh, Pennsylvania 15260, United States
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Angela M. Gronenborn
- Department
of Structural Biology, University of Pittsburgh
School of Medicine, Pittsburgh, Pennsylvania 15260, United States
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Lillian T. Chong
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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9
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Andrews B, Guerra J, Schweitzer-Stenner R, Urbanc B. Do molecular dynamics force fields accurately model Ramachandran distributions of amino acid residues in water? Phys Chem Chem Phys 2022; 24:3259-3279. [PMID: 35048087 DOI: 10.1039/d1cp05069a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Molecular dynamics (MD) is a powerful tool for studying intrinsically disordered proteins, however, its reliability depends on the accuracy of the force field. We assess Amber ff19SB, Amber ff14SB, OPLS-AA/M, and CHARMM36m with respect to their capacity to capture intrinsic conformational dynamics of 14 guest residues x (=G, A, L, V, I, F, Y, DP, EP, R, C, N, S, T) in GxG peptides in water. The MD-derived Ramachandran distribution of each guest residue is used to calculate 5 J-coupling constants and amide I' band profiles to facilitate a comparison to spectroscopic data through reduced χ2 functions. We show that the Gaussian model, optimized to best fit the experimental data, outperforms all MD force fields by an order of magnitude. The weaknesses of the MD force fields are: (i) insufficient variability of the polyproline II (pPII) population among the guest residues; (ii) oversampling of antiparallel at the expense of transitional β-strand region; (iii) inadequate sampling of turn-forming conformations for ionizable and polar residues; and (iv) insufficient guest residue-specificity of the Ramachandran distributions. Whereas Amber ff19SB performs worse than the other three force fields with respect to χ2 values, it accounts for residue-specific pPII content better than the other three force fields. Additional testing of residue-specific RSFF1 and Amber ff14SB combined with TIP4P/2005 on six guest residues x (=A, I, F, DP, R, S) reveals that residue specificity derived from protein coil libraries or an improved water model alone do not result in significantly lower χ2 values.
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Affiliation(s)
- Brian Andrews
- Department of Physics, Drexel University, Philadelphia, Pennsylvania, USA.
| | - Jose Guerra
- Department of Chemistry, Stony Brook University, Stony Brook, New York, USA
| | | | - Brigita Urbanc
- Department of Physics, Drexel University, Philadelphia, Pennsylvania, USA.
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10
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Santhouse JR, Leung JMG, Chong LT, Horne WS. Implications of the unfolded state in the folding energetics of heterogeneous-backbone protein mimetics. Chem Sci 2022; 13:11798-11806. [PMID: 36320921 PMCID: PMC9580521 DOI: 10.1039/d2sc04427g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/19/2022] [Indexed: 12/28/2022] Open
Abstract
Sequence-encoded folding is the foundation of protein structure and is also possible in synthetic chains of artificial chemical composition. In natural proteins, the characteristics of the unfolded state are as important as those of the folded state in determining folding energetics. While much is known about folded structures adopted by artificial protein-like chains, corresponding information about the unfolded states of these molecules is lacking. Here, we report the consequences of altered backbone composition on the structure, stability, and dynamics of the folded and unfolded states of a compact helix-rich protein. Characterization through a combination of biophysical experiments and atomistic simulation reveals effects of backbone modification that depend on both the type of artificial monomers employed and where they are applied in sequence. In general, introducing artificial connectivity in a way that reinforces characteristics of the unfolded state ensemble of the prototype natural protein minimizes the impact of chemical changes on folded stability. These findings have implications in the design of protein mimetics and provide an atomically detailed picture of the unfolded state of a natural protein and artificial analogues under non-denaturing conditions. Biophysical experiments and atomistic simulation reveal impacts of protein backbone alteration on the ensemble that defines the unfolded state. These effects have implications on folded stability of protein mimetics.![]()
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Affiliation(s)
| | - Jeremy M. G. Leung
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15211, USA
| | - Lillian T. Chong
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15211, USA
| | - W. Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15211, USA
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11
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Santhouse JR, Rao SR, Horne WS. Analysis of folded structure and folding thermodynamics in heterogeneous-backbone proteomimetics. Methods Enzymol 2021; 656:93-122. [PMID: 34325801 PMCID: PMC8392274 DOI: 10.1016/bs.mie.2021.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent years have seen a growing number of examples of designed oligomeric molecules with artificial backbone connectivity that are capable of adopting complex folded tertiary structures analogous to those seen in natural proteins. A range of experimental techniques from structural biology and biophysics have been brought to bear in the study of these proteomimetic agents. Here, we discuss some considerations encountered in the characterization of high-resolution folded structure as well as folding thermodynamics of protein-like artificial backbones. We provide an overview of the use of X-ray crystallography and NMR spectroscopy in such systems and review example applications of these methods in the primary literature. Further, we provide detailed protocols for two experiments that have proved useful in our prior and ongoing efforts to compare folding thermodynamics between natural protein domains and heterogeneous-backbone counterparts.
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Affiliation(s)
| | - Shilpa R Rao
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States
| | - W Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States.
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12
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Brooks CL, Case DA, Plimpton S, Roux B, van der Spoel D, Tajkhorshid E. Classical molecular dynamics. J Chem Phys 2021; 154:100401. [DOI: 10.1063/5.0045455] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Charles L. Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - David A. Case
- Department of Chemistry and Chemical Biology, Rutgers University, New Brunswick, New Jersey 08854, USA
| | - Steve Plimpton
- Computational Multiscale Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1316, USA
| | - Benoît Roux
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA
| | - David van der Spoel
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Theoretical and Computational Biophysics Group, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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