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Ertelt M, Mulligan VK, Maguire JB, Lyskov S, Moretti R, Schiffner T, Meiler J, Schoeder CT. Combining machine learning with structure-based protein design to predict and engineer post-translational modifications of proteins. PLoS Comput Biol 2024; 20:e1011939. [PMID: 38484014 DOI: 10.1371/journal.pcbi.1011939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 03/26/2024] [Accepted: 02/20/2024] [Indexed: 03/27/2024] Open
Abstract
Post-translational modifications (PTMs) of proteins play a vital role in their function and stability. These modifications influence protein folding, signaling, protein-protein interactions, enzyme activity, binding affinity, aggregation, degradation, and much more. To date, over 400 types of PTMs have been described, representing chemical diversity well beyond the genetically encoded amino acids. Such modifications pose a challenge to the successful design of proteins, but also represent a major opportunity to diversify the protein engineering toolbox. To this end, we first trained artificial neural networks (ANNs) to predict eighteen of the most abundant PTMs, including protein glycosylation, phosphorylation, methylation, and deamidation. In a second step, these models were implemented inside the computational protein modeling suite Rosetta, which allows flexible combination with existing protocols to model the modified sites and understand their impact on protein stability as well as function. Lastly, we developed a new design protocol that either maximizes or minimizes the predicted probability of a particular site being modified. We find that this combination of ANN prediction and structure-based design can enable the modification of existing, as well as the introduction of novel, PTMs. The potential applications of our work include, but are not limited to, glycan masking of epitopes, strengthening protein-protein interactions through phosphorylation, as well as protecting proteins from deamidation liabilities. These applications are especially important for the design of new protein therapeutics where PTMs can drastically change the therapeutic properties of a protein. Our work adds novel tools to Rosetta's protein engineering toolbox that allow for the rational design of PTMs.
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Affiliation(s)
- Moritz Ertelt
- Institute for Drug Discovery, Leipzig University Medical Faculty, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence ScaDS.AI, Dresden/Leipzig, Germany
| | - Vikram Khipple Mulligan
- Center for Computational Biology, Flatiron Institute, New York, New York, United States of America
| | - Jack B Maguire
- Program in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sergey Lyskov
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Rocco Moretti
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Torben Schiffner
- Institute for Drug Discovery, Leipzig University Medical Faculty, Leipzig, Germany
| | - Jens Meiler
- Institute for Drug Discovery, Leipzig University Medical Faculty, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence ScaDS.AI, Dresden/Leipzig, Germany
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Clara T Schoeder
- Institute for Drug Discovery, Leipzig University Medical Faculty, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence ScaDS.AI, Dresden/Leipzig, Germany
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Russell G, Zulfiqar F, Hancock JT. Hydrogenases and the Role of Molecular Hydrogen in Plants. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1136. [PMID: 32887396 PMCID: PMC7569912 DOI: 10.3390/plants9091136] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/27/2020] [Accepted: 08/31/2020] [Indexed: 12/17/2022]
Abstract
Molecular hydrogen (H2) has been suggested to be a beneficial treatment for a range of species, from humans to plants. Hydrogenases catalyze the reversible oxidation of H2, and are found in many organisms, including plants. One of the cellular effects of H2 is the selective removal of reactive oxygen species (ROS) and reactive nitrogen species (RNS), specifically hydroxyl radicals and peroxynitrite. Therefore, the function of hydrogenases and the action of H2 needs to be reviewed in the context of the signalling roles of a range of redox active compounds. Enzymes can be controlled by the covalent modification of thiol groups, and although motifs targeted by nitric oxide (NO) can be predicted in hydrogenases sequences it is likely that the metal prosthetic groups are the target of inhibition. Here, a selection of hydrogenases, and the possibility of their control by molecules involved in redox signalling are investigated using a bioinformatics approach. Methods of treating plants with H2 along with the role of H2 in plants is also briefly reviewed. It is clear that studies report significant effects of H2 on plants, improving growth and stress responses, and therefore future work needs to focus on the molecular mechanisms involved.
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Affiliation(s)
- Grace Russell
- Department of Applied Sciences, University of the West of England, Bristol BS 16 1QY, UK;
| | - Faisal Zulfiqar
- Institute of Horticultural Sciences, Faculty of Agriculture, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan;
| | - John T. Hancock
- Department of Applied Sciences, University of the West of England, Bristol BS 16 1QY, UK;
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Urmey AR, Zondlo NJ. Cysteine oxidation to the sulfinic acid induces oxoform-specific lanthanide binding and fluorescence in a designed peptide. Free Radic Biol Med 2020; 152:166-174. [PMID: 32097680 DOI: 10.1016/j.freeradbiomed.2020.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/30/2020] [Accepted: 02/19/2020] [Indexed: 10/24/2022]
Abstract
Cysteine sulfinic acid (Cys-SO2-) is a protein post-translational modification that is formed reversibly under oxidative conditions. A short, encodable peptide was developed whose metal binding and terbium luminescence are dependent on cysteine (Cys) oxidation to the sulfinic acid. The protein design is based on the modification of a key metal-binding aspartate (Asp) in a canonical EF-Hand motif (DKDADGWISPAEAK) to Cys. In this design, Cys in the thiol oxidation state does not mimic the native Asp, and thus the peptide binds terbium(III) (Tb3+) poorly and exhibits weak terbium luminescence (fluorescence). In contrast, when Cys is oxidized to the Cys sulfinic acid oxoform, the Cys sulfinate effectively mimics Asp, resulting in a significant increase in terbium affinity and luminescence. Asp residues at positions 1, 3, and 5 of the EF-Hand motif were examined as potential sites for Cys oxidation-responsive metal binding. The peptide with Cys at residue 1 exhibited the highest Tb3+ affinity in both oxidation states. The peptide with Cys at residue 3 exhibited a 4.2-fold distinction in affinity between the oxidation states. Most significantly, the peptide with Cys at residue 5 had only modest Tb3+ affinity as the Cys thiol, but exhibited a 30-fold increase in Tb3+ affinity and an 18-fold increase in Tb3+ luminescence on Cys oxidation to the sulfinic acid. This peptide (Ac-DKDACGWISPAEAK-NH2) exhibited selective Tb3+ binding via Cys-SO2- over the thiol, S-glutathionyl, S-nitrosyl, and sulfonic acid oxoforms, indicating substantially greater Lewis basicity of the sulfinate than the sulfonate. NMR spectroscopy and quantum homology modeling indicated that the designed peptide binds metal with an overall geometry similar to that of an EF-Hand motif, with the Cys sulfinate effectively replacing Asp as a metal-binding ligand. This peptide was applied to detect Cys oxidation to the sulfinic acid by fluorescence spectroscopy, suggesting its broader application in understanding Cys sulfinic acid biology.
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Affiliation(s)
- Andrew R Urmey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Neal J Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States.
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Urmey AR, Zondlo NJ. Design of a Protein Motif Responsive to Tyrosine Nitration and an Encoded Turn-Off Sensor of Tyrosine Nitration. Biochemistry 2019; 58:2822-2833. [PMID: 31140788 PMCID: PMC6688601 DOI: 10.1021/acs.biochem.9b00334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tyrosine nitration is a protein post-translational modification that is predominantly non-enzymatic and is observed to be increased under conditions of nitrosative stress and in numerous disease states. A small protein motif (14-18 amino acids) responsive to tyrosine nitration has been developed. In this design, nitrotyrosine replaced the conserved Glu12 of an EF-hand metal-binding motif. Thus, the non-nitrated peptide bound terbium weakly. In contrast, tyrosine nitration resulted in a 45-fold increase in terbium affinity. Nuclear magnetic resonance spectroscopy indicated direct binding of nitrotyrosine to the metal and EF-hand-like metal contacts in this designed peptide. Nitrotyrosine is an efficient quencher of fluorescence. To develop a sensor of tyrosine nitration, the initial design was modified to incorporate Glu residues at EF-hand positions 9 and 16 as additional metal-binding residues, to increase the terbium affinity of the peptide with unmodified tyrosine. This peptide with a tyrosine at residue 12 bound terbium and effectively sensitized terbium luminescence. Tyrosine nitration resulted in a 180-fold increase in terbium affinity ( Kd = 1.6 μM) and quenching of terbium luminescence. This sequence was incorporated as an encoded protein tag and applied as a turn-off fluorescent protein sensor of tyrosine nitration. The sensor was responsive to nitration by peroxynitrite, with fluorescence quenched upon nitration. The greater terbium affinity upon tyrosine nitration resulted in a large dynamic range and sensitivity to substoichiometric nitration. An improved approach for the synthesis of peptides containing nitrotyrosine was also developed, via the in situ silyl protection of nitrotyrosine. This work represents the first designed, encodable protein motif that is responsive to tyrosine nitration.
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Affiliation(s)
- Andrew R. Urmey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Neal J. Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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Gao F, Thornley BS, Tressler CM, Naduthambi D, Zondlo NJ. Phosphorylation-dependent protein design: design of a minimal protein kinase-inducible domain. Org Biomol Chem 2019; 17:3984-3995. [PMID: 30942803 PMCID: PMC6668337 DOI: 10.1039/c9ob00502a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein kinases and phosphatases modulate protein structure and function, which in turn regulate cellular activities. The development of novel proteins and protein motifs that are responsive to protein phosphorylation provides new ways to probe the functions of individual protein kinases and the intracellular effects of their activation and downregulation. Herein we develop a minimal motif that is responsive to protein phosphorylation, termed a minimal protein kinase-inducible domain. The encodable protein motif comprises a 7- or 8-residue sequence (DKDADXW or DKDADXXW), derived from EF-Hand calcium-binding domains, that is necessary but not sufficient for binding terbium, combined with a protein phosphorylation site (Ser or Thr at residue 9) that, upon phosphorylation, completes the metal-binding motif. Thus, the motif binds metal poorly and exhibits weak terbium luminescence when not phosphorylated. Upon phosphorylation, the peptide binds metal with significantly higher affinity and exhibits robust terbium luminescence. Phosphorylation results in up to a 23× increase in terbium luminescence. Minimal phosphorylation-dependent motifs as small as 9 residues (DKDADGWIS) were developed. NMR spectroscopy on this lanthanum(iii)·phosphopeptide complex confirmed that binding occurs in a manner similar to that in an EF-Hand, despite the absence of the conserved Glu12 typically present in an EF-Hand. By combining molecular design with known protein kinase recognition sequences, minimal protein kinase-inducible domains were developed that were responsive to phosphorylation by Protein Kinase A (PKA: DKDADRRW(S/pS)IIAK), Protein Kinase C (PKC: DKDADGWI(T/pT)FRRKA), and Casein Kinase 1 (CK1: DKDADDWA(S/pS)I). Phosphorylation by PKA was quantified in HeLa cell extracts, with a 4.4× increase in fluorescence (terbium luminescence) observed at 544 nm. The optimized minimal motif includes alternating aspartate residues at positions 1, 3, and 5, plus binding through the main-chain carbonyl at position 7; a lysine at position 2 to provide electrostatic balance and reduce binding in the absence of phosphorylation; an alanine at residue 4 to promote the αL conformation observed at that position of the EF Hand; a tryptophan at residue 7 or 8 to sensitize terbium luminescence; and a phosphorylation site with serine or threonine at residue 9. Residues at positions 6; 7 or 8; and 10 or later may be changed to provide kinase specificity. In the CK1-responsive peptide, the acidic residues in the proto-terbium-binding motif are employed as part of the kinase recognition sequence. This work thus presents fundamental rules for the design of compact phosphorylation-responsive terbium-binding motifs, with potential further application to motifs responsive to other protein post-translational modifications.
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Affiliation(s)
- Feng Gao
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
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