1
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Pham TL, Thomas F. Design of Functional Globular β-Sheet Miniproteins. Chembiochem 2024; 25:e202300745. [PMID: 38275210 DOI: 10.1002/cbic.202300745] [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: 10/31/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/27/2024]
Abstract
The design of discrete β-sheet peptides is far less advanced than e. g. the design of α-helical peptides. The reputation of β-sheet peptides as being poorly soluble and aggregation-prone often hinders active design efforts. Here, we show that this reputation is unfounded. We demonstrate this by looking at the β-hairpin and WW domain. Their structure and folding have been extensively studied and they have long served as model systems to investigate protein folding and folding kinetics. The resulting fundamental understanding has led to the development of hyperstable β-sheet scaffolds that fold at temperatures of 100 °C or high concentrations of denaturants. These have been used to design functional miniproteins with protein or nucleic acid binding properties, in some cases with such success that medical applications are conceivable. The β-sheet scaffolds are not always completely rigid, but can be specifically designed to respond to changes in pH, redox potential or presence of metal ions. Some engineered β-sheet peptides also exhibit catalytic properties, although not comparable to those of natural proteins. Previous reviews have focused on the design of stably folded and non-aggregating β-sheet sequences. In our review, we now also address design strategies to obtain functional miniproteins from β-sheet folding motifs.
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Affiliation(s)
- Truc Lam Pham
- Truc Lam Pham, Prof. Dr. Franziska Thomas, Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Franziska Thomas
- Truc Lam Pham, Prof. Dr. Franziska Thomas, Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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2
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Richaud AD, Mandal S, Das A, Roche SP. Tunable CH/π Interactions within a Tryptophan Zipper Motif to Stabilize the Fold of Long β-Hairpin Peptides. ACS Chem Biol 2023; 18:2555-2563. [PMID: 37976523 DOI: 10.1021/acschembio.3c00553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The tryptophan zipper (Trpzip) is an iconic folding motif of β-hairpin peptides capitalizing on two pairs of cross-strand tryptophans, each stabilized by an aromatic-aromatic stacking in an edge-to-face (EtF) geometry. Yet, the origins and the contribution of this EtF packing to the unique Trpzip stability remain poorly understood. To address this question of structure-stability relationship, a library of Trpzip hairpins was developed by incorporating readily accessible nonproteinogenic tryptophans of varying electron densities. We found that each EtF geometry was, in fact, stabilized by an intricate combination of XH/π interactions. By tuning the π-electron density of Trpface rings, CH/π interactions are strengthened to gain additional stability. On the contrary, our DFT calculations support the notion that Trpedge modulations are challenging due to their simultaneous paradoxical engagement as H-bond donors in CH/π and acceptors in NH/π interactions.
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Sourav Mandal
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pashan, Pune 411008, India
| | - Aloke Das
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pashan, Pune 411008, India
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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3
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Zhang J, Liu S, Li H, Tian X, Li X. Tryptophan-Based Self-Assembling Peptides with Bacterial Flocculation and Antimicrobial Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11316-11323. [PMID: 32907333 DOI: 10.1021/acs.langmuir.0c01957] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tryptophan as an aromatic amino acid with a hydrophobic indole group plays important roles in stabilizing protein structures and enhancing molecular bindings in nature, but was rarely used in the molecular design of self-assembling peptides or gelators. Therefore, we prepared a series of short peptides from Trp amino acids and examined the potential roles of Trp residues for regulating peptide self-assembly and gelation. The introduced Trp amino acids not only diversify the molecular structures of peptide gelators, but also promote aromatic and hydrogen-bonding interactions for supramolecular self-assembling and gelation, which generates self-assembled nanostructures with twisted helical morphologies and supramolecular hydrogels with low minimal gelation concentrations. More importantly, the self-assembling peptides with Trp residues displayed strong preference for interacting with the lipidic membranes of bacteria, which resulted in bacterial flocculation and the death of E. coli and S. aureus.
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Affiliation(s)
- Jikun Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Shengnan Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Hang Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Xin Tian
- School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou 215123, China
| | - Xinming Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
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4
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Sahoo JK, Nazareth C, VandenBerg MA, Webber MJ. Aromatic identity, electronic substitution, and sequence in amphiphilic tripeptide self-assembly. SOFT MATTER 2018; 14:9168-9174. [PMID: 30398280 DOI: 10.1039/c8sm01994k] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The phenomenon of self-assembly in short peptides (2-4 amino acids) has been a source of curiosity, in part for its role in helping to better understand and predict how minimal sequences within proteins might contribute to the formation of larger structures or aggregates. Building on previous work in this field, here we investigate a family of amphiphilic tripeptides for their self-assembly and hydrogel formation. From a parent peptide, Ac-FID-NH2, which was previously shown to self-assemble into high aspect-ratio filaments and form hydrogels, we explored the significance of structural features or sequence variations on the observed self-assembly. This process entailed substituting key aromatic residues, altering the electronics of these aromatic drivers of assembly, and screening tripeptide constitutional isomers. This work more clearly elucidates the mechanisms and design parameters that govern the creation of materials from short peptide building blocks, as well as offering greater insight into the interactions between minimal segments of proteins that underlie their structure and aggregation.
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Affiliation(s)
- Jugal Kishore Sahoo
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, IN 46556, USA.
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5
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Mortenson DE, Kreitler DF, Thomas NC, Guzei IA, Gellman SH, Forest KT. Evaluation of β-Amino Acid Replacements in Protein Loops: Effects on Conformational Stability and Structure. Chembiochem 2018; 19:604-612. [PMID: 29272560 DOI: 10.1002/cbic.201700580] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Indexed: 01/16/2023]
Abstract
β-Amino acids have a backbone that is expanded by one carbon atom relative to α-amino acids, and β residues have been investigated as subunits in protein-like molecules that adopt discrete and predictable conformations. Two classes of β residue have been widely explored in the context of generating α-helix-like conformations: β3 -amino acids, which are homologous to α-amino acids and bear a side chain on the backbone carbon adjacent to nitrogen, and residues constrained by a five-membered ring, such the one derived from trans-2-aminocyclopentanecarboxylic acid (ACPC). Substitution of α residues with their β3 homologues within an α-helix-forming sequence generally causes a decrease in conformational stability. Use of a ring-constrained β residue, however, can offset the destabilizing effect of α→β substitution. Here we extend the study of α→β substitutions, involving both β3 and ACPC residues, to short loops within a small tertiary motif. We start from previously reported variants of the Pin1 WW domain that contain a two-, three-, or four-residue β-hairpin loop, and we evaluate α→β replacements at each loop position for each variant. By referral to the ϕ,ψ angles of the native structure, one can choose a stereochemically appropriate ACPC residue. Use of such logically chosen ACPC residues enhances conformational stability in several cases. Crystal structures of three β-containing Pin1 WW domain variants show that a native-like tertiary structure is maintained in each case.
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Affiliation(s)
- David E Mortenson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Dale F Kreitler
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Nicole C Thomas
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Ilia A Guzei
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Samuel H Gellman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Katrina T Forest
- Departments of Chemistry and Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI, 53706, USA
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6
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Parappurath A, Abraham JN. Novel Pentadecyl Phenol-Tagged L-Tryptophan Molecules: Synthesis, Self- Assembly and Liquid Crystalline Properties. ChemistrySelect 2018. [DOI: 10.1002/slct.201702171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Akhil Parappurath
- Polymer Science and Engineering Division CSIR-National Chemical Laboratory; Dr. Homibhabha road Pune India - 411008
| | - Jancy Nixon Abraham
- Polymer Science and Engineering Division CSIR-National Chemical Laboratory; Dr. Homibhabha road Pune India - 411008
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7
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Anderson JM, Andersen NH. A pH Switch for β-Sheet Protein Folding. Angew Chem Int Ed Engl 2017; 56:7074-7077. [PMID: 28523654 PMCID: PMC5607017 DOI: 10.1002/anie.201700860] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/26/2017] [Indexed: 01/24/2023]
Abstract
Protein design advancements have led to biotechnological strategies based on more stable and more specific structures. Herein we present a 6-residue sequence (HPATGK) that acts as a stable structure-nucleating turn at physiological and higher pH but is notably unfavorable for chain direction reversal at low pH. When placed into the turn of a β-sheet, this leads to a pH switch of folding. Using a standard 3-stranded β-sheet model, the WW domain, it was found that the pH switch sequence insertion caused minimal change at pH 8 but a ca. 50 °C drop in the melting temperature (Tm ) was observed at pH 2.5: ΔΔGF ≥11.3 kJ mol-1 . Using the strategies demonstrated in this article, the redesign of β-sheets to contain a global, or local, pH-dependent conformational switch should be possible.
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8
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A pH Switch for β-Sheet Protein Folding. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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9
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Haridas V, Kumar PPP, Bhardwaj I, Venugopalan P. Spatially Placed Tryptophan Residues: A Strategy for Generating Molecules with Unique Self-Assembly and Molecular Recognition Properties. ChemistrySelect 2017. [DOI: 10.1002/slct.201601569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- V. Haridas
- Department of Chemistry; Indian Institute of Technology Delhi; New Delhi− 110016 India
| | - P. P. Praveen Kumar
- Department of Chemistry; Indian Institute of Technology Delhi; New Delhi− 110016 India
| | - Ishanki Bhardwaj
- Department of Chemistry; Indian Institute of Technology Delhi; New Delhi− 110016 India
| | - P. Venugopalan
- Department of chemistry; Panjab University; Chandigarh India
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10
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Haridas V, Sadanandan S, Dhawan S, Mishra R, Jain I, Goel G, Hu Y, Patel S. Synthetic minimalistic tryptophan zippers as a chiroptical switch. Org Biomol Chem 2017; 15:1661-1669. [DOI: 10.1039/c6ob02617f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Supramolecular helices with left and right handed chirality were designed and synthesized based on l-tryptophan that undergo helical inversion upon addition of H2PO4−.
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Affiliation(s)
- V. Haridas
- Department of Chemistry
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Sandhya Sadanandan
- Department of Chemistry
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Sameer Dhawan
- Department of Chemistry
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Rituraj Mishra
- Department of Chemistry
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Ishani Jain
- Department of Chemical Engineering
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Gaurav Goel
- Department of Chemical Engineering
- Indian Institute of Technology Delhi
- New Delhi 110016
- India
| | - Yuan Hu
- Department of Chemistry and Biochemistry
- University of Delaware
- Newark
- USA
| | - Sandeep Patel
- Department of Chemistry and Biochemistry
- University of Delaware
- Newark
- USA
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11
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Hsu CH, Park S, Mortenson DE, Foley BL, Wang X, Woods RJ, Case DA, Powers ET, Wong CH, Dyson HJ, Kelly JW. The Dependence of Carbohydrate-Aromatic Interaction Strengths on the Structure of the Carbohydrate. J Am Chem Soc 2016; 138:7636-48. [PMID: 27249581 DOI: 10.1021/jacs.6b02879] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Interactions between proteins and carbohydrates are ubiquitous in biology. Therefore, understanding the factors that determine their affinity and selectivity are correspondingly important. Herein, we have determined the relative strengths of intramolecular interactions between a series of monosaccharides and an aromatic ring close to the glycosylation site in an N-glycoprotein host. We employed the enhanced aromatic sequon, a structural motif found in the reverse turns of some N-glycoproteins, to facilitate face-to-face monosaccharide-aromatic interactions. A protein host was used because the dependence of the folding energetics on the identity of the monosaccharide can be accurately measured to assess the strength of the carbohydrate-aromatic interaction. Our data demonstrate that the carbohydrate-aromatic interaction strengths are moderately affected by changes in the stereochemistry and identity of the substituents on the pyranose rings of the sugars. Galactose seems to make the weakest and allose the strongest sugar-aromatic interactions, with glucose, N-acetylglucosamine (GlcNAc) and mannose in between. The NMR solution structures of several of the monosaccharide-containing N-glycoproteins were solved to further understand the origins of the similarities and differences between the monosaccharide-aromatic interaction energies. Peracetylation of the monosaccharides substantially increases the strength of the sugar-aromatic interaction in the context of our N-glycoprotein host. Finally, we discuss our results in light of recent literature regarding the contribution of electrostatics to CH-π interactions and speculate on what our observations imply about the absolute conservation of GlcNAc as the monosaccharide through which N-linked glycans are attached to glycoproteins in eukaryotes.
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Affiliation(s)
- Che-Hsiung Hsu
- Department of Molecular and Experimental Medicine, The Scripps Research Institute , La Jolla, California 92037, United States.,Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Sangho Park
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - David E Mortenson
- Department of Molecular and Experimental Medicine, The Scripps Research Institute , La Jolla, California 92037, United States
| | - B Lachele Foley
- Complex Carbohydrate Research Center, University of Georgia , 315 Riverbend Road, Athens, Georgia 30602, United States
| | - Xiaocong Wang
- Complex Carbohydrate Research Center, University of Georgia , 315 Riverbend Road, Athens, Georgia 30602, United States
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia , 315 Riverbend Road, Athens, Georgia 30602, United States
| | - David A Case
- Department of Chemistry and Chemical Biology, Rutgers University , Piscataway, New Jersey 08854, United States
| | - Evan T Powers
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Chi-Huey Wong
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States.,Genomics Research Center, Academia Sinica , Taipei 115, Taiwan.,The Skaggs Institute for Chemical Biology , La Jolla, California 92037, United States
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Jeffery W Kelly
- Department of Molecular and Experimental Medicine, The Scripps Research Institute , La Jolla, California 92037, United States.,Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States.,The Skaggs Institute for Chemical Biology , La Jolla, California 92037, United States
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12
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Anderson JM, Kier BL, Jurban B, Byrne A, Shu I, Eidenschink LA, Shcherbakov AA, Hudson M, Fesinmeyer RM, Andersen NH. Aryl-aryl interactions in designed peptide folds: Spectroscopic characteristics and optimal placement for structure stabilization. Biopolymers 2016; 105:337-356. [PMID: 26850220 PMCID: PMC5638712 DOI: 10.1002/bip.22821] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/01/2016] [Accepted: 02/03/2016] [Indexed: 01/27/2023]
Abstract
We have extended our studies of Trp/Trp to other Aryl/Aryl through-space interactions that stabilize hairpins and other small polypeptide folds. Herein we detail the NMR and CD spectroscopic features of these types of interactions. NMR data remains the best diagnostic for characterizing the common T-shape orientation. Designated as an edge-to-face (EtF or FtE) interaction, large ring current shifts are produced at the edge aryl ring hydrogens and, in most cases, large exciton couplets appear in the far UV circular dichroic (CD) spectrum. The preference for the face aryl in FtE clusters is W ≫ Y ≥ F (there are some exceptions in the Y/F order); this sequence corresponds to the order of fold stability enhancement and always predicts the amplitude of the lower energy feature of the exciton couplet in the CD spectrum. The CD spectra for FtE W/W, W/Y, Y/W, and Y/Y pairs all include an intense feature at 225-232 nm. An additional couplet feature seen for W/Y, W/F, Y/Y, and F/Y clusters, is a negative feature at 197-200 nm. Tyr/Tyr (as well as F/Y and F/F) interactions produce much smaller exciton couplet amplitudes. The Trp-cage fold was employed to search for the CD effects of other Trp/Trp and Trp/Tyr cluster geometries: several were identified. In this account, we provide additional examples of the application of cross-strand aryl/aryl clusters for the design of stable β-sheet models and a scale of fold stability increments associated with all possible FtE Ar/Ar clusters in several structural contexts. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 337-356, 2016.
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Affiliation(s)
- Jordan M Anderson
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - Brandon L Kier
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - Brice Jurban
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - Aimee Byrne
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - Irene Shu
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | | | | | - Mike Hudson
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - R M Fesinmeyer
- Department of Chemistry, University of Washington, Seattle, WA, 98195
| | - Niels H Andersen
- Department of Chemistry, University of Washington, Seattle, WA, 98195
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13
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Makwana KM, Mahalakshmi R. Stereopositional Outcome in the Packing of Dissimilar Aromatics in Designed β-Hairpins. Chemistry 2016; 22:4147-56. [DOI: 10.1002/chem.201504428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/15/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Kamlesh Madhusudan Makwana
- Molecular Biophysics Laboratory; Department of Biological Sciences; Indian Institute of Science Education and Research, Bhopal; 462023 Madhya Pradesh India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory; Department of Biological Sciences; Indian Institute of Science Education and Research, Bhopal; 462023 Madhya Pradesh India
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14
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Davis CM, Dyer RB. The Role of Electrostatic Interactions in Folding of β-Proteins. J Am Chem Soc 2016; 138:1456-64. [PMID: 26750867 DOI: 10.1021/jacs.5b13201] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Atomic-level molecular dynamic simulations are capable of fully folding structurally diverse proteins; however, they are limited in their ability to accurately represent electrostatic interactions. Here we have experimentally tested the role of charged residues on stability and folding kinetics of one of the most widely simulated β-proteins, the WW domain. The folding of wild type Pin1 WW domain, which has two positively charged residues in the first turn, was compared to the fast folding mutant FiP35 Pin1, which introduces a negative charge into the first turn. A combination of FTIR spectroscopy and laser-induced temperature-jump coupled with infrared spectroscopy was used to probe changes in the amide I region. The relaxation dynamics of the peptide backbone, β-sheets and β-turns, and negatively charged aspartic acid side chain of FiP35 were measured independently by probing the corresponding bands assigned in the amide I region. Folding is initiated in the turns and the β-sheets form last. While the global folding mechanism is in good agreement with simulation predictions, we observe changes in the protonation state of aspartic acid during folding that have not been captured by simulation methods. The protonation state of aspartic acid is coupled to protein folding; the apparent pKa of aspartic acid in the folded protein is 6.4. The dynamics of the aspartic acid follow the dynamics of the intermediate phase, supporting assignment of this phase to formation of the first hairpin. These results demonstrate the importance of electrostatic interactions in turn stability and formation of extended β-sheet structures.
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Affiliation(s)
- Caitlin M Davis
- Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States
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15
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Madhusudan Makwana K, Mahalakshmi R. Implications of aromatic-aromatic interactions: From protein structures to peptide models. Protein Sci 2015; 24:1920-33. [PMID: 26402741 DOI: 10.1002/pro.2814] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 09/17/2015] [Accepted: 09/18/2015] [Indexed: 12/11/2022]
Abstract
With increasing structural information on proteins, the opportunity to understand physical forces governing protein folding is also expanding. One of the significant non-covalent forces between the protein side chains is aromatic-aromatic interactions. Aromatic interactions have been widely exploited and thoroughly investigated in the context of folding, stability, molecular recognition, and self-assembly processes. Through this review, we discuss the contribution of aromatic interactions to the activity and stability of thermophilic, mesophilic, and psychrophilic proteins. Being hydrophobic, aromatic amino acids tend to reside in the protein hydrophobic interior or transmembrane segments of proteins. In such positions, it can play a diverse role in soluble and membrane proteins, and in α-helix and β-sheet stabilization. We also highlight here some excellent investigations made using peptide models and several approaches involving aryl-aryl interactions, as an increasingly popular strategy in protein and peptide engineering. A recent survey described the existence of aromatic clusters (trimer, tetramer, pentamer, and higher order assemblies), revealing the self-associating property of aryl groups, even in folded protein structures. The application of this self-assembly of aromatics in the generation of modern bionanomaterials is also discussed.
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Affiliation(s)
- Kamlesh Madhusudan Makwana
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462023, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462023, India
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16
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Makwana KM, Mahalakshmi R. NMR Analysis of Tuning Cross-Strand Phe/Tyr/Trp-Trp Interactions in Designed β-Hairpin Peptides: Terminal Switch from L to D Amino Acid as a Strategy for β-Hairpin Capping. J Phys Chem B 2015; 119:5376-85. [PMID: 25849307 DOI: 10.1021/acs.jpcb.5b00554] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Interaction among the side chains of aromatic amino acids is a well-known mechanism of protein and peptide structure stabilization, particularly in β sheets. Using short β-hairpin models bearing the sequence Ac-Leu-Xxx-Val-DPro-Gly-Leu-Trp-Val-NH2, we report the surprising observation of significant destabilization in aryl–tryptophan interactions, which results in poorly folded peptide populations accompanied by lowering of stability. We find that such destabilization arises from forced occupancy of the indole ring in the shielded Edge position, in T-shaped aryl geometries. We demonstrate that this destabilizing effect can be efficiently salvaged by replacing the N-terminal LLeu with DLeu, which causes an increase in the folded hairpin population, while retaining Trp in the Edge position. Our observation of unique cross strand NOEs and data from temperature-dependent NMR and CD measurements reveals the formation of a locally stabilized aliphatic–aromatic network, leading to an overall increase in ΔGF° by ∼ −0.6 to −1.2 kcal/mol. Our results suggest that a contextual evaluation of stabilization by tryptophan is necessary in β hairpins. Furthermore, we report for the first time that the use of D isomers of aliphatic amino acids at the terminus is stabilizing, which can serve as a new strategy for increasing β-hairpin stability.
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Affiliation(s)
- Kamlesh M Makwana
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462023, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462023, India
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17
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Liao Y, Zhang SM, Neo TL, Tam JP. Tryptophan-dependent membrane interaction and heteromerization with the internal fusion peptide by the membrane proximal external region of SARS-CoV spike protein. Biochemistry 2015; 54:1819-30. [PMID: 25668103 DOI: 10.1021/bi501352u] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The spike (S) protein of severe acute respiratory syndrome-associated CoV (SARS-CoV) mediates membrane fusion and viral entry. These events involve structural rearrangements, including heteromerization between two heptad repeats (HR1 and HR2) to form a trimer of dimers as a six-helix bundle (6-HB), a quaternary protein structure that brings two distant clusters of hydrophobic sequences into the proximity of each other, the internal fusion peptide (IFP) preceding HR1, and the highly conserved tryptophan (Trp)-rich membrane proximal external region (MPER) following HR2. Here, we show that MPER can undergo self-oligomerization and heteromerization with IFP, events that are Trp-dependent. To delineate the roles of Trp residues of MPER in forming these quaternary structures and interacting with membranes, we employed a panel of synthetic peptides: MPER peptide (M-wt) and its alanine (Ala) and phenylalanine (Phe) analogues. Ala substitutions of Trp inhibited its association with cellular membranes. Chemical cross-linking experiments showed that M-wt can self-interact to form oligomers and cross-interact with IFP23, a synthetic IFP peptide, to form a heterohexamer. In comparison, little high-order oligomer was formed between M-wt and fusion peptide. The specific interaction between M-wt and IFP23 was confirmed by immunofluorescence staining experiments. In aqueous solutions, both M-wt and IFP23 displayed random secondary structures that became helical in hydrophobic solvents. Triple-Ala substitutions of Trp in M-wt, but not the corresponding triple-Phe analogue, disrupted oligomerization of M-wt and hetero-oligomerization of M-wt with IFP23. Overall, our results show that Trp residues of MPER play a key role in maintaining the structure and functions of MPER, allowing it to interact with IFP to form a MPER-IFP heteromer, a putative quaternary structure extending from the 6-HB, and function in membrane fusion. Finally, we showed that a MPER peptide could serve as an inhibitor in the entry process.
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Affiliation(s)
- Ying Liao
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551
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18
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Lawrence PB, Gavrilov Y, Matthews SS, Langlois MI, Shental-Bechor D, Greenblatt HM, Pandey BK, Smith MS, Paxman R, Torgerson CD, Merrell JP, Ritz CC, Prigozhin MB, Levy Y, Price JL. Criteria for Selecting PEGylation Sites on Proteins for Higher Thermodynamic and Proteolytic Stability. J Am Chem Soc 2014; 136:17547-60. [DOI: 10.1021/ja5095183] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Paul B. Lawrence
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Yulian Gavrilov
- Department
of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sam S. Matthews
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Minnie I. Langlois
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Dalit Shental-Bechor
- Department
of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M. Greenblatt
- Department
of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Brijesh K. Pandey
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Mason S. Smith
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Ryan Paxman
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Chad D. Torgerson
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Jacob P. Merrell
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Cameron C. Ritz
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Maxim B. Prigozhin
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Yaakov Levy
- Department
of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Joshua L. Price
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
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19
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Makwana KM, Mahalakshmi R. Asymmetric contribution of aromatic interactions stems from spatial positioning of the interacting aryl pairs in β-hairpins. Chembiochem 2014; 15:2357-60. [PMID: 25196944 DOI: 10.1002/cbic.201402340] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Indexed: 11/11/2022]
Abstract
Isolated aromatic interactions in designed octapeptide β-hairpin scaffolds display a near-universal T-shaped face-to-edge geometry in all positional permutations, with the exception of aryl-Trp interactions. The heterogeneous asymmetric indole ring of Trp competes for a "shielding" face geometry, which lowers the scaffold stability in FtE aryl-Trp pairs. Assessment of the contributions of aryl pairs (in the absence of solvent-driven interactions) to the overall β-hairpin structure reveals the superiority of Trp-Phe and Trp-Tyr contributions over the well-established scaffold stabilization by Trp-Trp.
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Affiliation(s)
- Kamlesh Madhusudan Makwana
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh 462023 (India)
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20
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Kier BL, Anderson JM, Andersen NH. Circular permutation of a WW domain: folding still occurs after excising the turn of the folding-nucleating hairpin. J Am Chem Soc 2014; 136:741-9. [PMID: 24350581 PMCID: PMC4051316 DOI: 10.1021/ja410824x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A hyperstable Pin1 WW domain has been circularly permuted via excision of the fold-nucleating turn; it still folds to form the native three-strand sheet and hydrophobic core features. Multiprobe folding dynamics studies of the normal and circularly permuted sequences, as well as their constituent hairpin fragments and comparable-length β-strand-loop-β-strand models, indicate 2-state folding for all topologies. N-terminal hairpin formation is the fold nucleating event for the wild-type sequence; the slower folding circular permutant has a more distributed folding transition state.
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Affiliation(s)
- Brandon L. Kier
- Department of Chemistry, University of Washington, Seattle, WA 98195
| | | | - Niels H. Andersen
- Department of Chemistry, University of Washington, Seattle, WA 98195
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21
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Makwana KM, Mahalakshmi R. Comparative analysis of cross strand aromatic–Phe interactions in designed peptide β-hairpins. Org Biomol Chem 2014; 12:2053-61. [DOI: 10.1039/c3ob42247j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Examination of the preferential interaction geometries of the aromatic amino acids Phe, Tyr and Trp with the benzyl ring of Phe in designed octapeptide hairpin scaffolds reveals stabilizing contributions of a Trp–Phe pair, even in amphipathic solvents.
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Affiliation(s)
- Kamlesh Madhusudan Makwana
- Molecular Biophysics Laboratory
- Department of Biological Sciences
- Indian Institute of Science Education and Research
- Bhopal, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory
- Department of Biological Sciences
- Indian Institute of Science Education and Research
- Bhopal, India
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22
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Nair RV, Kotmale AS, Dhokale SA, Gawade RL, Puranik VG, Rajamohanan PR, Sanjayan GJ. Formation of a pseudo-β-hairpin motif utilizing the Ant–Pro reverse turn: consequences of stereochemical reordering. Org Biomol Chem 2014; 12:774-82. [DOI: 10.1039/c3ob42016g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report a special case of pseudo-β-hairpin formation by tetrapeptide sequences featuring a two-residue Ant–Pro dipeptide motif (Ant = anthranilic acid and Pro = proline) at the loop region.
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Affiliation(s)
- Roshna V. Nair
- Division of Organic Synthesis
- National Chemical Laboratory
- Pune 411 008, India
| | - Amol S. Kotmale
- Central Material Characterization Division
- National Chemical Laboratory
- Pune 411 008, India
| | - Snehal A. Dhokale
- Central Material Characterization Division
- National Chemical Laboratory
- Pune 411 008, India
| | - Rupesh L. Gawade
- Central NMR Facility
- National Chemical Laboratory
- Pune 411 008, India
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23
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Abstract
Since the first report in 1993 (JACS 115, 5887-5888) of a peptide able to form a monomeric β-hairpin structure in aqueous solution, the design of peptides forming either β-hairpins (two-stranded antiparallel β-sheets) or three-stranded antiparallel β-sheets has become a field of growing interest and activity. These studies have yielded great insights into the principles governing the stability and folding of β-hairpins and antiparallel β-sheets. This chapter provides an overview of the reported β-hairpin/β-sheet peptides focussed on the applied design criteria, reviews briefly the factors contributing to β-hairpin/β-sheet stability, and describes a protocol for the de novo design of β-sheet-forming peptides based on them. Guidelines to select appropriate turn and strand residues and to avoid self-association are provided. The methods employed to check the success of new designed peptides are also summarized. Since NMR is the best technique to that end, NOEs and chemical shifts characteristic of β-hairpins and three-stranded antiparallel β-sheets are given.
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Affiliation(s)
- M Angeles Jiménez
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Química Física Rocasolano (IQFR), Serrano 119, 28006, Madrid, Spain,
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24
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Aluminum(III) interferes with the structure and the activity of the peptidyl-prolyl cis-trans isomerase (Pin1): A new mechanism contributing to the pathogenesis of Alzheimer's disease and cancers? J Inorg Biochem 2013; 126:111-7. [DOI: 10.1016/j.jinorgbio.2013.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 12/25/2022]
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25
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Tang HC, Lin YJ, Horng JC. Modulating the folding stability and ligand binding affinity of Pin1 WW domain by proline ring puckering. Proteins 2013; 82:67-76. [DOI: 10.1002/prot.24359] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/13/2013] [Accepted: 06/25/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Hsu-Cheng Tang
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Yu-Ju Lin
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Jia-Cherng Horng
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters; National Tsing Hua University; Hsinchu 30013 Taiwan
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26
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Statistical Analysis of Terminal Extensions of Protein β-Strand Pairs. Adv Bioinformatics 2013; 2013:909436. [PMID: 23424587 PMCID: PMC3569888 DOI: 10.1155/2013/909436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Revised: 12/30/2012] [Accepted: 12/30/2012] [Indexed: 11/17/2022] Open
Abstract
The long-range interactions, required to the accurate predictions of tertiary structures of β-sheet-containing proteins, are still difficult to simulate. To remedy this problem and to facilitate β-sheet structure predictions, many efforts have been made by computational methods. However, known efforts on β-sheets mainly focus on interresidue contacts or amino acid partners. In this study, to go one step further, we studied β-sheets on the strand level, in which a statistical analysis was made on the terminal extensions of paired β-strands. In most cases, the two paired β-strands have different lengths, and terminal extensions exist. The terminal extensions are the extended part of the paired strands besides the common paired part. However, we found that the best pairing required a terminal alignment, and β-strands tend to pair to make bigger common parts. As a result, 96.97% of β-strand pairs have a ratio of 25% of the paired common part to the whole length. Also 94.26% and 95.98% of β-strand pairs have a ratio of 40% of the paired common part to the length of the two β-strands, respectively. Interstrand register predictions by searching interacting β-strands from several alternative offsets should comply with this rule to reduce the computational searching space to improve the performances of algorithms.
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27
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Patel S, Mathonet P, Jaulent AM, Ullman CG. Selection of a high-affinity WW domain against the extracellular region of VEGF receptor isoform-2 from a combinatorial library using CIS display. Protein Eng Des Sel 2013; 26:307-15. [PMID: 23378640 DOI: 10.1093/protein/gzt003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
WW domains are small β-sheet motifs that are involved in intracellular signalling through the recognition of proline-rich or phosphorylated linear peptide sequences. Here, we describe modification of this motif to provide a framework for engineering the side chains exposed on its concave surface. This non-natural scaffold incorporates an additional tryptophan, has a shorter loop 1 and supports modification of 25% of the natural protein to form a novel affinity reagent. We demonstrate the utility of this structure by selecting a high-affinity binder to the extracellular region of human vascular endothelial growth factor receptor isoform 2 (VEGFR-2) from a library of modifications, using a cell-free molecular display platform, CIS display. The isolate has low nanomolar affinity to VEGFR-2 and inhibits binding of human VEGF to its receptor with nanomolar activity. The structure is amenable to cyclisation to improve its proteolytic stability and has advantages over larger protein scaffolds in that it can be synthesised chemically to high yields offering potential for therapeutic and non-therapeutic applications.
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Affiliation(s)
- Seema Patel
- Isogenica Ltd, Little Chesterford, Essex CB10 1XL, UK
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28
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Wang JZ, Xi L, Zhu GF, Han YG, Luo Y, Wang M, Du LF. The acidic pH-induced structural changes in Pin1 as revealed by spectral methodologies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 98:199-206. [PMID: 22986147 DOI: 10.1016/j.saa.2012.07.105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 07/27/2012] [Accepted: 07/27/2012] [Indexed: 06/01/2023]
Abstract
Pin1 is closely associated with the pathogenesis of cancers and Alzheimer's disease (AD). Previously, we have shown the characteristics of the thermal denaturation of Pin1. Herein, the acid-induced denaturation of Pin1 was determined by means of fluorescence emission, synchronous fluorescence, far-UV CD, ANS fluorescence and RLS spectroscopies. The fluorescence emission spectra and the synchronous fluorescence spectra suggested the partially reversible unfolding (approximately from pH 7.0 to 4.0) and refolding (approximately from pH 4.0 to 1.0) of the structures around the chromophores in Pin1, apparently with an intermediate state at about pH 4.0-4.5. The far-UV CD spectra indicated that acidic pH (below pH 4.0) induced the structural transition from α-helix and random coils to β-sheet in Pin1. The ANS fluorescence and the RLS spectra further suggested the exposure of the hydrophobic side-chains of Pin1 and the aggregation of it especially below pH 2.3, and the aggregation possibly resulted in the formation of extra intermolecular β-sheet. The present work primarily shows that acidic pH can induce kinds of irreversible structural changes in Pin1, such as the exposure of the hydrophobic side-chains, the transition from α-helix to β-sheet and the aggregation of Pin1, and also explains why Pin1 loses most of its activity below pH 5.0. The results emphasize the important role of decreased pH in the pathogenesis of some Pin1-related diseases, and support the therapeutic approach for them by targeting acidosis and modifying the intracellular pH gradients.
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Affiliation(s)
- Jing-Zhang Wang
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, PR China
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29
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Zhang N, Feng Y, Gao S, Ruan J, Zhang T. New insights regarding protein folding as learned from beta-sheets. EXCLI JOURNAL 2012; 11:543-55. [PMID: 27540347 PMCID: PMC4983712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/22/2012] [Indexed: 10/28/2022]
Abstract
The folding of denatured proteins into their native conformations is called Anfinsen's dogma, and is the rationale for predicting protein structures based on primary sequences. Through the last 40 years of study, all available algorithms which either predict 3D or 2D protein structures, or predict the rate of protein folding based on the amino acid sequence alone, are limited in accuracy (80 %). This fact has led some researchers to look for the lost information, from mRNA to protein sequences, and it encourages us to rethink the rationale of Anfinsen's dogma. In this study, we focus on the relationship between the strand and its partners. We find two rules based on a non-redundant dataset taken from the PDB database. We refer to these two rules as the "first coming first pairing" rule and the "loveless" rule. The first coming first pairing rule indicates that a given strand prefers to pair with the next strand, if the connected region is flexible enough. The loveless rule means that the affinities between a given strand and another strand are comparable to the affinity between the given strand and its partner. Of course, the affinities between the given strand and a helix/coil peptide are significantly less than the affinity between the given strand and its partner. These two rules suggest that in protein folding, we have folding taking place during translation, and suggest also that a denatured protein is not the same as its primary sequence. Rechecking the original Anfinsen experiments, we find that the method used to denature protein in the experiment simply breaks the disulfide bonds, while the helices and sheets remain intact. In other words, denatured proteins still retain all helices and beta sheets, while the primary sequence does not. Although further verification via biological experiments is needed, our results as shown in this study may reveal a new insight for studying protein folding.
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Affiliation(s)
- Ning Zhang
- Department of Biomedical Engineering, Tianjin University, Tianjin Key Lab of BME Measurement, Tianjin, 300072, PR China,College of Life Sciences, Nankai University, Tianjin, PR China, 300071
| | - Yuanming Feng
- Department of Biomedical Engineering, Tianjin University, Tianjin Key Lab of BME Measurement, Tianjin, 300072, PR China
| | - Shan Gao
- College of Life Sciences, Nankai University, Tianjin, PR China, 300071,College of Mathematical Science, Nankai University, Tianjin 300071, PR China
| | - Jishou Ruan
- College of Mathematical Science, Nankai University, Tianjin 300071, PR China,State Key Laboratory for Medical Chemical and Biology at Nankai University, Tianjin, PR China, 300071,*To whom correspondence should be addressed: Jishou Ruan, College of Mathematical Science, Nankai University, Tianjin 300071, PR China; Tel: +86 022 23501449, E-mail:
| | - Tao Zhang
- College of Life Sciences, Nankai University, Tianjin, PR China, 300071
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30
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Price JL, Culyba EK, Chen W, Murray AN, Hanson SR, Wong CH, Powers ET, Kelly JW. N-glycosylation of enhanced aromatic sequons to increase glycoprotein stability. Biopolymers 2012; 98:195-211. [PMID: 22782562 PMCID: PMC3539202 DOI: 10.1002/bip.22030] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/17/2012] [Accepted: 01/26/2012] [Indexed: 11/12/2022]
Abstract
N-glycosylation can increase the rate of protein folding, enhance thermodynamic stability, and slow protein unfolding; however, the molecular basis for these effects is incompletely understood. Without clear engineering guidelines, attempts to use N-glycosylation as an approach for stabilizing proteins have resulted in unpredictable energetic consequences. Here, we review the recent development of three "enhanced aromatic sequons," which appear to facilitate stabilizing native-state interactions between Phe, Asn-GlcNAc and Thr when placed in an appropriate reverse turn context. It has proven to be straightforward to engineer a stabilizing enhanced aromatic sequon into glycosylation-naïve proteins that have not evolved to optimize specific protein-carbohydrate interactions. Incorporating these enhanced aromatic sequons into appropriate reverse turn types within proteins should enhance the well-known pharmacokinetic benefits of N-glycosylation-based stabilization by lowering the population of protease-susceptible unfolded and aggregation-prone misfolded states, thereby making such proteins more useful in research and pharmaceutical applications.
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Affiliation(s)
- Joshua L. Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Elizabeth K. Culyba
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Wentao Chen
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Amber N. Murray
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Sarah R. Hanson
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Chi-Huey Wong
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Evan T. Powers
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
| | - Jeffery W. Kelly
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037
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31
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Bandyopadhyay A, Mali SM, Lunawat P, Raja KMP, Gopi HN. Synthesis and Structural Investigations of Functionalizable Hybrid β-Hairpin. Org Lett 2011; 13:4482-5. [DOI: 10.1021/ol201840p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anupam Bandyopadhyay
- Department of Chemistry, Indian Institute of Science Education and Research, Garware Circle, Pashan, Pune-411 021, India, and Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, India
| | - Sachitanand M. Mali
- Department of Chemistry, Indian Institute of Science Education and Research, Garware Circle, Pashan, Pune-411 021, India, and Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, India
| | - Pooja Lunawat
- Department of Chemistry, Indian Institute of Science Education and Research, Garware Circle, Pashan, Pune-411 021, India, and Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, India
| | - K. Muruga Poopathi Raja
- Department of Chemistry, Indian Institute of Science Education and Research, Garware Circle, Pashan, Pune-411 021, India, and Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, India
| | - Hosahudya N. Gopi
- Department of Chemistry, Indian Institute of Science Education and Research, Garware Circle, Pashan, Pune-411 021, India, and Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, India
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32
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Santiveri CM, Jiménez MA. Tryptophan residues: scarce in proteins but strong stabilizers of β-hairpin peptides. Biopolymers 2011; 94:779-90. [PMID: 20564027 DOI: 10.1002/bip.21436] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tryptophan plays important roles in protein stability and recognition despite its scarcity in proteins. Except as fluorescent groups, they have been used rarely in peptide design. Nevertheless, Trp residues were crucial for the stability of some designed minimal proteins. In 2000, Trp-Trp pairs were shown to contribute more than any other hydrophobic interaction to the stability of β-hairpin peptides. Since then, Trp-Trp pairs have emerged as a paradigm for the design of stable β-hairpins, such as the Trpzip peptides. Here, we analyze the nature of the stabilizing capacity of Trp-Trp pairs by reviewing the β-hairpin peptides containing Trp-Trp pairs described up to now, the spectroscopic features and geometry of the Trp-Trp pairs, and their use as binding sites in β-hairpin peptides. To complete the overview, we briefly go through the other relevant β-hairpin stabilizing Trp-non-Trp interactions and illustrate the use of Trp in the design of short peptides adopting α-helical and mixed α/β motifs. This review is of interest in the field of rational design of proteins, peptides, peptidomimetics, and biomaterials.
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Affiliation(s)
- Clara M Santiveri
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, Madrid 28006, Spain
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33
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Stewart AL, Park JH, Waters ML. Redesign of a WW domain peptide for selective recognition of single-stranded DNA. Biochemistry 2011; 50:2575-84. [PMID: 21332166 DOI: 10.1021/bi101116a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A β-sheet miniprotein based on the FBP11 WW1 domain sequence has been redesigned for the molecular recognition of ssDNA. A previous report showed that a β-hairpin peptide dimer, (WKWK)(2), binds ssDNA with low micromolar affinity but with little selectivity over duplex DNA. This report extends those studies to a three-stranded β-sheet miniprotein designed to mimic the OB-fold. The new peptide binds ssDNA with low micromolar affinity and shows about 10-fold selectivity for ssDNA over duplex DNA. The redesigned peptide no longer binds its native ligand, the polyproline helix, confirming that the peptide has been redesigned for the function of binding ssDNA. Structural studies provide evidence that this peptide consists of a well-structured β-hairpin made of strands 2 and 3 with a less structured first strand that provides affinity for ssDNA but does not improve the stability of the full peptide. These studies provide insight into protein-DNA interactions as well as a novel example of protein redesign.
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Affiliation(s)
- Amanda L Stewart
- Department of Chemistry, CB 3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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Santiveri CM, Pérez de Vega MJ, González-Muñiz R, Jiménez MA. Trp-Trp pairs as β-hairpin stabilisers: Hydrogen-bonded versus non-hydrogen-bonded sites. Org Biomol Chem 2011; 9:5487-92. [DOI: 10.1039/c1ob05353a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Price JL, Shental-Bechor D, Dhar A, Turner MJ, Powers ET, Gruebele M, Levy Y, Kelly JW. Context-dependent effects of asparagine glycosylation on Pin WW folding kinetics and thermodynamics. J Am Chem Soc 2010; 132:15359-67. [PMID: 20936810 PMCID: PMC2965790 DOI: 10.1021/ja106896t] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Asparagine glycosylation is one of the most common and important post-translational modifications of proteins in eukaryotic cells. N-glycosylation occurs when a triantennary glycan precursor is transferred en bloc to a nascent polypeptide (harboring the N-X-T/S sequon) as the peptide is cotranslationally translocated into the endoplasmic reticulum (ER). In addition to facilitating binding interactions with components of the ER proteostasis network, N-glycans can also have intrinsic effects on protein folding by directly altering the folding energy landscape. Previous work from our laboratories (Hanson et al. Proc. Natl. Acad. Sci. U.S.A. 2009, 109, 3131-3136; Shental-Bechor, D.; Levy, Y. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 8256-8261) suggested that the three sugar residues closest to the protein are sufficient for accelerating protein folding and stabilizing the resulting structure in vitro; even a monosaccharide can have a dramatic effect. The highly conserved nature of these three proximal sugars in N-glycans led us to speculate that introducing an N-glycosylation site into a protein that is not normally glycosylated would stabilize the protein and increase its folding rate in a manner that does not depend on the presence of specific stabilizing protein-saccharide interactions. Here, we test this hypothesis experimentally and computationally by incorporating an N-linked GlcNAc residue at various positions within the Pin WW domain, a small β-sheet-rich protein. The results show that an increased folding rate and enhanced thermodynamic stability are not general, context-independent consequences of N-glycosylation. Comparison between computational predictions and experimental observations suggests that generic glycan-based excluded volume effects are responsible for the destabilizing effect of glycosylation at highly structured positions. However, this reasoning does not adequately explain the observed destabilizing effect of glycosylation within flexible loops. Our data are consistent with the hypothesis that specific, evolved protein-glycan contacts must also play an important role in mediating the beneficial energetic effects on protein folding that glycosylation can confer.
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Affiliation(s)
- Joshua L. Price
- Departments of Chemistry and Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Dalit Shental-Bechor
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel, 76100
| | - Apratim Dhar
- Center for Biophysics and Computational Biology and Departments of Chemistry and Physics, University of Illinois, Urbana, Illinois 61801
| | - Maurice J. Turner
- Departments of Chemistry and Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Evan T. Powers
- Departments of Chemistry and Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Martin Gruebele
- Center for Biophysics and Computational Biology and Departments of Chemistry and Physics, University of Illinois, Urbana, Illinois 61801
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel, 76100
| | - Jeffery W. Kelly
- Departments of Chemistry and Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037
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Abstract
Although much has been learned about the design of models of beta-sheets during the last decade, modest fold stabilities in water and terminal fraying remain a feature of most beta-hairpin peptides. In the case of hairpin capping, nature did not provide guidance for solving the problem. Some observations from prior turn capping designs, with further optimization, have provided a generally applicable, "unnatural" beta cap motif (alkanoyl-Trp at the N terminus and Trp-Thr-Gly at the C terminus) that provides a net contribution of 6 + kJ/mol to beta-hairpin stability, surpassing all other interactions that stabilize beta-hairpins including the covalent disulfide bond. The motif, made up entirely of natural residues, is specific to the termini of antiparallel beta-strands and reduces fraying at the ends of hairpins and other beta-sheet models. Utilizing this motif, 10- to 22-residue peptide scaffolds of defined stereochemistry that are greater than 98% folded in water have been prepared. The beta-cap can also be used to staple together short antiparallel beta-strands connected by a long flexible loop.
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Wu L, McElheny D, Takekiyo T, Keiderling TA. Geometry and Efficacy of Cross-Strand Trp/Trp, Trp/Tyr, and Tyr/Tyr Aromatic Interaction in a β-Hairpin Peptide. Biochemistry 2010; 49:4705-14. [DOI: 10.1021/bi100491s] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ling Wu
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, Illinois 60607-7061
| | - Dan McElheny
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, Illinois 60607-7061
| | - Takahiro Takekiyo
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, Illinois 60607-7061
| | - Timothy A. Keiderling
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, Illinois 60607-7061
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Zhang N, Duan G, Gao S, Ruan J, Zhang T. Prediction of the parallel/antiparallel orientation of beta-strands using amino acid pairing preferences and support vector machines. J Theor Biol 2010; 263:360-8. [PMID: 20035768 DOI: 10.1016/j.jtbi.2009.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/05/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
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Wu L, McElheny D, Huang R, Keiderling TA. Role of Tryptophan−Tryptophan Interactions in Trpzip β-Hairpin Formation, Structure, and Stability. Biochemistry 2009; 48:10362-71. [PMID: 19788311 DOI: 10.1021/bi901249d] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ling Wu
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061
| | - Dan McElheny
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061
| | - Rong Huang
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061
| | - Timothy A. Keiderling
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061
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Jäger M, Dendle M, Kelly JW. Sequence determinants of thermodynamic stability in a WW domain--an all-beta-sheet protein. Protein Sci 2009; 18:1806-13. [PMID: 19565466 DOI: 10.1002/pro.172] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The stabilities of 66 sequence variants of the human Pin1 WW domain have been determined by equilibrium thermal denaturation experiments. All 34 residues composing the hPin1 WW three-stranded beta-sheet structure could be replaced one at a time with at least one different natural or non-natural amino acid residue without leading to an unfolded protein. Alanine substitutions at only four positions within the hPin1 WW domain lead to a partially or completely unfolded protein-in the absence of a physiological ligand. The side chains of these four residues form a conserved, partially solvent-inaccessible, continuous hydrophobic minicore comprising the N- and C-termini. Ala mutations at five other residues, three of which constitute the ligand binding patch on the concave side of the beta-sheet, significantly destabilize the hPin1 WW domain without leading to an unfolded protein. The remaining mutations affect protein stability only slightly, suggesting that only a small subset of side chain interactions within the hPin1 WW domain are mandatory for acquiring and maintaining a stable, cooperatively folded beta-sheet structure.
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Affiliation(s)
- Marcus Jäger
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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41
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Zhang N, Ruan J, Duan G, Gao S, Zhang T. The interstrand amino acid pairs play a significant role in determining the parallel or antiparallel orientation of beta-strands. Biochem Biophys Res Commun 2009; 386:537-43. [PMID: 19540200 DOI: 10.1016/j.bbrc.2009.06.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 06/16/2009] [Indexed: 12/12/2022]
Abstract
It is widely considered that it is not appropriate to treat beta-pairs in isolation, since other secondary structural models (such as helices, coils), protein topology and protein tertiary structures would limit beta-strand pairing. However, to understand the underlying mechanisms of beta-sheet formation, studies ought to be performed separately on more concrete aspects. In this study, we focus on the parallel or antiparallel orientation of beta-strands. First, statistical analysis was performed on the relative frequencies of the interstrand amino acid pairs within parallel and antiparallel beta-strands. Consequently, features were extracted by singular value decomposition from the statistical results. By using the support vector machine to distinguish the features extracted from the two types of beta-strands, high accuracy was achieved (up to 99.4%). This suggests that the interstrand amino acid pairs play a significant role in determining the parallel or antiparallel orientation of beta-strands. These results may provide useful information for developing other useful algorithms to examine to the beta-strand folding pathways, and could eventually lead to protein structure predictions.
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Affiliation(s)
- Ning Zhang
- Key Laboratory of Bioactive Materials, Ministry of Education and College of Life Science, Nankai University, Tianjin 300071, PR China
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42
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Eidenschink L, Kier BL, Huggins KNL, Andersen NH. Very short peptides with stable folds: building on the interrelationship of Trp/Trp, Trp/cation, and Trp/backbone-amide interaction geometries. Proteins 2009; 75:308-22. [PMID: 18831035 PMCID: PMC2656586 DOI: 10.1002/prot.22240] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
By combining a favorable turn sequence with a turn flanking Trp/Trp interaction and a C-terminal H-bonding interaction between a backbone amide and an i-2 Trp ring, a particularly stable (DeltaG(U) > 7 kJ/mol) truncated hairpin, Ac-WI-(D-Pro-D-Asn)-KWTG-NH(2), results. In this construct and others with a W-(4-residue turn)-W motif in severely truncated hairpins, the C-terminal Trp is the edge residue in a well-defined face-to-edge (FtE) aryl/aryl interaction. Longer hairpins and those with six-residue turns retain the reversed "edge-to-face" (EtF) Trp/Trp geometry first observed for the trpzip peptides. Mutational studies suggest that the W-(4-residue turn)-W interaction provides at least 3 kJ/mol of stabilization in excess of that due to the greater beta-propensity of Trp. The pi-cation, and Trp/Gly-H(N) interactions have been defined. The latter can give rise to >3 ppm upfield shifts for the Gly-H(N) in -WX(n)G- units both in turns (n = 2) and at the C-termini (n = 1) of hairpins. Terminal YTG units result in somewhat smaller shifts (extrapolated to 2 ppm for 100% folding). In peptides with both the EtF and FtE W/W interaction geometries, Trp to Tyr mutations indicate that Trp is the preferred "face" residue in aryl/aryl pairings, presumably because of its greater pi basicity.
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Affiliation(s)
- Lisa Eidenschink
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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43
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Mirassou Y, Santiveri CM, Pérez de Vega MJ, González-Muñiz R, Jiménez MA. Disulfide Bonds versus Trp⋅⋅⋅Trp Pairs in Irregular β-Hairpins: NMR Structure of Vammin Loop 3-Derived Peptides as a Case Study. Chembiochem 2009; 10:902-10. [DOI: 10.1002/cbic.200800834] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Jager M, Deechongkit S, Koepf EK, Nguyen H, Gao J, Powers ET, Gruebele M, Kelly JW. Understanding the mechanism of beta-sheet folding from a chemical and biological perspective. Biopolymers 2009; 90:751-8. [PMID: 18844292 DOI: 10.1002/bip.21101] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Perturbing the structure of the Pin1 WW domain, a 34-residue protein comprised of three beta-strands and two intervening loops has provided significant insight into the structural and energetic basis of beta-sheet folding. We will review our current perspective on how structure acquisition is influenced by the sequence, which determines local conformational propensities and mediates the hydrophobic effect, hydrogen bonding, and analogous intramolecular interactions. We have utilized both traditional site-directed mutagenesis and backbone mutagenesis approaches to alter the primary structure of this beta-sheet protein. Traditional site-directed mutagenesis experiments are excellent for altering side-chain structure, whereas amide-to-ester backbone mutagenesis experiments modify backbone-backbone hydrogen bonding capacity. The transition state structure associated with the folding of the Pin1 WW domain features a partially H-bonded, near-native reverse turn secondary structure in loop 1 that has little influence on thermodynamic stability. The thermodynamic stability of the Pin1 WW domain is largely determined by the formation of a small hydrophobic core and by the formation of desolvated backbone-backbone H-bonds enveloped by this hydrophobic core. Loop 1 engineering to the consensus five-residue beta-bulge-turn found in most WW domains or a four-residue beta-turn found in most beta-hairpins accelerates folding substantially relative to the six-residue turn found in the wild type Pin1 WW domain. Furthermore, the more efficient five- and four-residue reverse turns now contribute to the stability of the three-stranded beta-sheet. These insights have allowed the design of Pin1 WW domains that fold at rates that approach the theoretical speed limit of folding.
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Affiliation(s)
- Marcus Jager
- Department of Chemistry, Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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45
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Kier BL, Andersen NH. Probing the lower size limit for protein-like fold stability: ten-residue microproteins with specific, rigid structures in water. J Am Chem Soc 2008; 130:14675-83. [PMID: 18842046 DOI: 10.1021/ja804656h] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mutational optimization of two long-range interactions first observed in Ac-WINGKWT-NH2, (a) bifurcated H-bonding involving the threonine amide H(N) and side chain OH and the N-terminal acetyl carbonyl and (b) an H-bond between the entgegen-H(N) of the C-terminal amide and the indole ring of Trp6 that stabilizes a face-to-edge indole/indole interaction between Trp1 and Trp6, has afforded < or = 10 residue systems that yield a remarkably stable fold in water. Optimization was achieved by designing a hydrophobic cluster that sequesters these H-bonds from solvent exposure. The structures and extent of amide H/D exchange protection for CH3CH2CO-WI pGXWTGPS (p = D-Pro, X = Leu or Ile) were determined. These two systems are greater than 94% folded at 298 K (97.5% at 280 K) with melting temperatures > 75 degrees C. The fold appears to display minimal fluxionality; a well-converged NMR structure rationalizes all of the large structuring shifts observed, and we suggest that these designed constructs can be viewed as microproteins.
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Affiliation(s)
- Brandon L Kier
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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46
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Schaeffer RD, Fersht A, Daggett V. Combining experiment and simulation in protein folding: closing the gap for small model systems. Curr Opin Struct Biol 2008; 18:4-9. [PMID: 18242977 DOI: 10.1016/j.sbi.2007.11.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Accepted: 11/29/2007] [Indexed: 11/30/2022]
Abstract
All-atom molecular dynamics (MD) simulations on increasingly powerful computers have been combined with experiments to characterize protein folding in detail over wider time ranges. The folding of small ultrafast folding proteins is being simulated on micros timescales, leading to improved structural predictions and folding rates. To what extent is 'closing the gap' between simulation and experiment for such systems providing insights into general mechanisms of protein folding?
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Affiliation(s)
- R Dustin Schaeffer
- Biomolecular Structure & Design Program, University of Washington, Seattle, WA 98195, USA
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