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Ibarra AA, Bartlett GJ, Hegedüs Z, Dutt S, Hobor F, Horner KA, Hetherington K, Spence K, Nelson A, Edwards TA, Woolfson DN, Sessions RB, Wilson AJ. Predicting and Experimentally Validating Hot-Spot Residues at Protein-Protein Interfaces. ACS Chem Biol 2019; 14:2252-2263. [PMID: 31525028 PMCID: PMC6804253 DOI: 10.1021/acschembio.9b00560] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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Protein–protein
interactions (PPIs) are vital to all biological
processes. These interactions are often dynamic, sometimes transient,
typically occur over large topographically shallow protein surfaces,
and can exhibit a broad range of affinities. Considerable progress
has been made in determining PPI structures. However, given the above
properties, understanding the key determinants of their thermodynamic
stability remains a challenge in chemical biology. An improved ability
to identify and engineer PPIs would advance understanding of biological
mechanisms and mutant phenotypes and also provide a firmer foundation
for inhibitor design. In silico prediction of PPI
hot-spot amino acids using computational alanine scanning (CAS) offers
a rapid approach for predicting key residues that drive protein–protein
association. This can be applied to all known PPI structures; however
there is a trade-off between throughput and accuracy. Here we describe
a comparative analysis of multiple CAS methods, which highlights effective
approaches to improve the accuracy of predicting hot-spot residues.
Alongside this, we introduce a new method, BUDE Alanine Scanning,
which can be applied to single structures from crystallography and
to structural ensembles from NMR or molecular dynamics data. The comparative
analyses facilitate accurate prediction of hot-spots that we validate
experimentally with three diverse targets: NOXA-B/MCL-1 (an α-helix-mediated
PPI), SIMS/SUMO, and GKAP/SHANK-PDZ (both β-strand-mediated
interactions). Finally, the approach is applied to the accurate prediction
of hot-spot residues at a topographically novel Affimer/BCL-xL protein–protein interface.
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Affiliation(s)
- Amaurys A. Ibarra
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, U.K
| | - Gail J. Bartlett
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Zsöfia Hegedüs
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Som Dutt
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Fruzsina Hobor
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Katherine A. Horner
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Kristina Hetherington
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Kirstin Spence
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Adam Nelson
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Thomas A. Edwards
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Derek N. Woolfson
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, U.K
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, U.K
| | - Richard B. Sessions
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, U.K
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, U.K
| | - Andrew J. Wilson
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
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Fletcher JM, Horner KA, Bartlett GJ, Rhys GG, Wilson AJ, Woolfson DN. De novo coiled-coil peptides as scaffolds for disrupting protein-protein interactions. Chem Sci 2018; 9:7656-7665. [PMID: 30393526 PMCID: PMC6182421 DOI: 10.1039/c8sc02643b] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/06/2018] [Indexed: 02/06/2023] Open
Abstract
Homo- and hetero-dimeric coiled coils as scaffolds for the presentation of α-helical protein-binding motifs.
Protein–protein interactions (PPIs) play pivotal roles in the majority of biological processes. Therefore, improved approaches to target and disrupt PPIs would provide tools for chemical biology and leads for therapeutic development. PPIs with α-helical components are appealing targets given that the secondary structure is well understood and can be mimicked or stabilised to render small-molecule and constrained-peptide-based inhibitors. Here we present a strategy to target α-helix-mediated PPIs that exploits de novo coiled-coil assemblies and test this using the MCL-1/NOXA-B PPI. First, computational alanine scanning is used to identify key α-helical residues from NOXA-B that contribute to the interface. Next, these residues are grafted onto the exposed surfaces of de novo designed homodimeric or heterodimeric coiled-coil peptides. The resulting synthetic peptides selectively inhibit a cognate MCL-1/BID complex in the mid-nM range. Furthermore, the heterodimeric system affords control as inhibition occurs only when both the grafted peptide and its designed partner are present. This establishes proof of concept for exploiting peptides stabilised in de novo coiled coils as inhibitors of PPIs. This dependence on supramolecular assembly introduces new possibilities for regulation and control.
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Affiliation(s)
- Jordan M Fletcher
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK . ;
| | - Katherine A Horner
- School of Chemistry , University of Leeds , Woodhouse Lane , Leeds LS2 9JT , UK.,Astbury Centre for Structural Molecular Biology , University of Leeds , Woodhouse Lane , Leeds , LS2 9JT , UK
| | - Gail J Bartlett
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK . ;
| | - Guto G Rhys
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK . ;
| | - Andrew J Wilson
- School of Chemistry , University of Leeds , Woodhouse Lane , Leeds LS2 9JT , UK.,Astbury Centre for Structural Molecular Biology , University of Leeds , Woodhouse Lane , Leeds , LS2 9JT , UK
| | - Derek N Woolfson
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK . ; .,School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK.,BrisSynBio , University of Bristol , Life Sciences Building, Tyndall Avenue , Bristol , BS8 1TQ , UK
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Abstract
Strain-promoted inverse electron-demand Diels–Alder cycloaddition (SPIEDAC) reactions between 1,2,4,5-tetrazines and strained dienophiles, such as bicyclononynes, are among the fastest bioorthogonal reactions. However, the synthesis of 1,2,4,5-tetrazines is complex and can involve volatile reagents. 1,2,4-Triazines also undergo cycloaddition reactions with acyclic and unstrained dienophiles at elevated temperatures, but their reaction with strained alkynes has not been described. We postulated that 1,2,4-triazines would react with strained alkynes at low temperatures and therefore provide an alternative to the tetrazine cycloaddition reaction for use in in vitro or in vivo labelling experiments. We describe the synthesis of a 1,2,4-triazin-3-ylalanine derivative fully compatible with the fluorenylmethyloxycarbonyl (Fmoc) strategy for peptide synthesis and demonstrate its reaction with strained bicyclononynes at 37 °C with rates comparable to the reaction of azides with the same substrates. The synthetic route to triazinylalanine is readily adaptable to late-stage functionalization of other probe molecules, and the 1,2,4-triazine-SPIEDAC therefore has potential as an alternative to tetrazine cycloaddition for applications in cellular and biochemical studies.
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Affiliation(s)
- Katherine A Horner
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, LS2 9JT Leeds (UK)
| | - Nathalie M Valette
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, LS2 9JT Leeds (UK)
| | - Michael E Webb
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane, LS2 9JT Leeds (UK).
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Horner KA, Adams DH, Hanson GR, Keefe KA. Blockade of stimulant-induced preprodynorphin mRNA expression in the striatal matrix by serotonin depletion. Neuroscience 2005; 131:67-77. [PMID: 15680692 DOI: 10.1016/j.neuroscience.2004.10.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2004] [Indexed: 11/18/2022]
Abstract
Cocaine and methamphetamine (METH) induce preprodynorphin (PPD) mRNA expression in the striatum. Cocaine induces PPD expression in both the patch and matrix compartments of the rostral striatum, whereas METH induces PPD expression in the patch compartment of the rostral striatum. In middle striatum, both stimulants increase PPD expression in the patch and matrix compartments. METH and cocaine treatment also increase extracellular serotonin (5-HT). Several studies have shown that 5-HT receptors are present on striatonigral neurons that express PPD mRNA, and that 5-HT is a positive regulator of striatal neuropeptide expression. The current study examined whether 5-HT plays a role in the patch/matrix expression of PPD mRNA induced by cocaine and METH in striatum. Male Sprague-Dawley rats were treated with p-chloroamphetamine (PCA; 8 mg/kg, i.p), a serotonin neurotoxin, 1 week prior to cocaine (30 mg/kg, i.p) and METH (15 mg/kg, s.c.) treatment. The 80% loss of 5-HT induced by PCA-pretreatment blocked cocaine-induced PPD expression in the rostral matrix compartment. Cocaine- and METH-induced PPD expression in the rostral patch compartment was unaffected by PCA-pretreatment. PCA-pretreatment also decreased both cocaine- and METH-induced PPD expression in the matrix, but not patch of middle striatum. PCA-induced 5-HT depletion did not affect stimulant-induced increases in PPT mRNA expression in the striatum. These data suggest that 5-HT plays a role in stimulant-induced PPD expression in the matrix compartment of rostral and middle striatum. Thus, 5-HT innervation may play a critical role in basal ganglia function.
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Affiliation(s)
- K A Horner
- Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Room 201, Salt Lake City, UT 84112, USA.
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Abstract
Opiate-modulating tetrapeptides such as tyrosine-melanocyte-stimulating hormone-release inhibiting factor-1 (Tyr-MIF-1; Tyr-Pro-Leu-Gly-NH2) and Tyr-W-MIF-1 (Tyr-Pro-Trp-Gly-NH2) are saturably transported from brain to blood. We examined whether two recently described endogenous opiate tetrapeptides with similar structures, the mu-specific endomorphins, also are transported across the blood-brain barrier (BBB). We found that the efflux rates of endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) were each self-inhibited by an excess of the respective endomorphin, thereby defining saturable transport. Cross-inhibition of the transport of each endomorphin by the other indicated shared transport. By contrast, no inhibition of the efflux of either endomorphin resulted from coadministration of Tyr-MIF-1, indicating that peptide transport system-1 (PTS-1) was not involved. Tyr-W-MIF-1, which is partially transported by PTS-1, significantly (P<0.01) decreased the transport of endomorphin-1 and tended (P=0.051) to decrease the transport of endomorphin-2, consistent with its role as both an opiate and antiopiate. Although involved in modulation of pain, coinjection of calcitonin gene-related peptide or constriction of the sciatic nerve did not appear to inhibit endomorphin efflux. Thus, the results demonstrate the existence of a new efflux system across the BBB which saturably transports endomorphins from brain to blood.
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Affiliation(s)
- A J Kastin
- VA Medical Center and Tulane University School of Medicine, New Orleans, LA 70112-1262, USA
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Dufau ML, Tsuruhara T, Horner KA, Podesta E, Catt KJ. Intermediate role of adenosine 3':5'-cyclic monophosphate and protein kinase during gonadotropin-induced steroidogenesis in testicular interstitial cells. Proc Natl Acad Sci U S A 1977; 74:3419-23. [PMID: 198785 PMCID: PMC431588 DOI: 10.1073/pnas.74.8.3419] [Citation(s) in RCA: 146] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Discrepancies between adenosine 3':5'-cyclic monophosphate (cAMP) and steroid production have been frequently observed in isolated target cells stimulated by low concentrations of trophic hormone. This dissociation is particularly marked in the interstitial cells of the testis, where testosterone production is elicited by gonadotropin concentrations in the picomolar range. Because of these observations, and a disparity between steroidogenesis and protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) activation in Leydig cells, the role of cAMP as a mediator of the acute steroidogenic response has been questioned. This problem has been further analyzed by assay of free and occupied cAMP-binding sites of the regulatory subunit of protein kinase in basal and hormone-stimulated cells. Free sites were measured by a [(3)H]-cAMP-binding assay, and occupied sites were measured by radioimmunoassay of endogenous cAMP eluted from receptor protein. After stimulation of purified Leydig cells with 0.1-10 pM human chorionic gonadotropin, a dose-dependent decrease in available [(3)H]cAMP-binding sites was observed, with no change in binding affinity. The reduction in cAMP-binding sites was equivalent to the increase in occupancy of cAMP receptors by endogenous nucleotide formed during gonadotropin action. Fractional occupancy of cAMP receptors rose progressively from basal values of 0.2-0.40 to full saturation as intracellular cAMP rose 10- to 30-fold during hormone stimulation. The testosterone dose-response curve was coincident with the initial part of the cAMP-receptor occupancy curve. These changes in endogenous cAMP binding to the regulatory subunit were accompanied by a significant increase in protein kinase activity in gonadotropin-stimulated Leydig cells. These observations provide direct evidence for the role of cAMP and protein kinase during hormonal activation of steroidogenesis in the Leydig cell by low concentrations of gonadotropin.
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