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Navarro J. Fine-Tuning of GPCR-Chemokine Interactions. Design and Identification of Chemokine Analogues as Receptor Agonists, Biased Agonists, and Antagonists. Biochemistry 2019; 58:1432-1439. [PMID: 30726064 DOI: 10.1021/acs.biochem.8b01266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemokines play important roles in immune defense by directing migration of leukocytes and serve as key promoters of tumorigenesis and metastasis. This study explores the molecular mechanisms of recognition and activation of two homologous chemokine receptors, CXCR1 and CXCR2, using CXCL8 analogues with residue substitutions in the conserved Glu4Leu5Arg6 (ELR) triad. Analysis of the binding of CXCL8 analogues to CXCR1 is consistent with the two-site model for signal recognition of CXCR1, whereas analysis of the binding of CXCL8 analogues to CXCR2 supported a single-site model for signal recognition of CXCR2. The CXCL8-Arg6His analogue stimulated calcium release, phosphorylation of ERK1/2, and chemotaxis in cells expressing CXCR1. However, CXCL8-Arg6His failed to stimulate calcium release and chemotaxis in cells expressing CXCR2, although it stimulated phosphorylation of ERK1/2, indicating that CXCL8-Arg6His operated as a classical CXCR2 biased agonist. The CXCL8-Glu4AlaLeu5AlaArg6His analogue was inactive in cells expressing CXCR1 and CXCR2. These findings suggest that the Glu4Leu5 motif in CXCL8 is essential for activation of CXCR1 and CXCR2. Importantly, CXCL8-Glu4AlaLeu5AlaArg6His blocked specifically the calcium release and chemotaxis of cells expressing CXCR1 but not of cells expressing CXCR2. CXCL8-Glu4AlaLeu5AlaArg6His was identified as the first specific CXCR1 antagonist. The binding of CXCL8-ELR6H to CXCR1 created a Zn2+ coordination site at the receptor activation domain responsible for calcium release, as ZnCl2 specifically blocked CXCL8-Arg6His-induced calcium release without affecting CXCL8-induced calcium release. This work provides the basis for further exploration of the activation mechanisms of chemokine receptors and will assist in the design of the next generation of modulators of CXCR1 and CXCR2.
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Affiliation(s)
- Javier Navarro
- Department of Neuroscience, Cell Biology and Anatomy, School of Medicine, Sealy Center for Structural Biology and Molecular Biophysics , University of Texas Medical Branch , Galveston , Texas 77555 , United States
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Park SH, Berkamp S, Radoicic J, De Angelis AA, Opella SJ. Interaction of Monomeric Interleukin-8 with CXCR1 Mapped by Proton-Detected Fast MAS Solid-State NMR. Biophys J 2018; 113:2695-2705. [PMID: 29262362 DOI: 10.1016/j.bpj.2017.09.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/17/2017] [Accepted: 09/21/2017] [Indexed: 12/01/2022] Open
Abstract
The human chemokine interleukin-8 (IL-8; CXCL8) is a key mediator of innate immune and inflammatory responses. This small, soluble protein triggers a host of biological effects upon binding and activating CXCR1, a G protein-coupled receptor, located in the cell membrane of neutrophils. Here, we describe 1H-detected magic angle spinning solid-state NMR studies of monomeric IL-8 (1-66) bound to full-length and truncated constructs of CXCR1 in phospholipid bilayers under physiological conditions. Cross-polarization experiments demonstrate that most backbone amide sites of IL-8 (1-66) are immobilized and that their chemical shifts are perturbed upon binding to CXCR1, demonstrating that the dynamics and environments of chemokine residues are affected by interactions with the chemokine receptor. Comparisons of spectra of IL-8 (1-66) bound to full-length CXCR1 (1-350) and to N-terminal truncated construct NT-CXCR1 (39-350) identify specific chemokine residues involved in interactions with binding sites associated with N-terminal residues (binding site-I) and extracellular loop and helical residues (binding site-II) of the receptor. Intermolecular paramagnetic relaxation enhancement broadening of IL-8 (1-66) signals results from interactions of the chemokine with CXCR1 (1-350) containing Mn2+ chelated to an unnatural amino acid assists in the characterization of the receptor-bound form of the chemokine.
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Affiliation(s)
- Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Sabrina Berkamp
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Jasmina Radoicic
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Anna A De Angelis
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Stanley J Opella
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California.
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Berkamp S, Park SH, De Angelis AA, Marassi FM, Opella SJ. Structure of monomeric Interleukin-8 and its interactions with the N-terminal Binding Site-I of CXCR1 by solution NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2017; 69:111-121. [PMID: 29143165 PMCID: PMC5869024 DOI: 10.1007/s10858-017-0128-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/18/2017] [Indexed: 06/07/2023]
Abstract
The structure of monomeric human chemokine IL-8 (residues 1-66) was determined in aqueous solution by NMR spectroscopy. The structure of the monomer is similar to that of each subunit in the dimeric full-length protein (residues 1-72), with the main differences being the location of the N-loop (residues 10-22) relative to the C-terminal α-helix and the position of the side chain of phenylalanine 65 near the truncated dimerization interface (residues 67-72). NMR was used to analyze the interactions of monomeric IL-8 (1-66) with ND-CXCR1 (residues 1-38), a soluble polypeptide corresponding to the N-terminal portion of the ligand binding site (Binding Site-I) of the chemokine receptor CXCR1 in aqueous solution, and with 1TM-CXCR1 (residues 1-72), a membrane-associated polypeptide that includes the same N-terminal portion of the binding site, the first trans-membrane helix, and the first intracellular loop of the receptor in nanodiscs. The presence of neither the first transmembrane helix of the receptor nor the lipid bilayer significantly affected the interactions of IL-8 with Binding Site-I of CXCR1.
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Affiliation(s)
- Sabrina Berkamp
- Department of Chemistry and Biochemistry, University of California, San Diego La Jolla, San Diego, CA, 92093-0307, USA
| | - Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego La Jolla, San Diego, CA, 92093-0307, USA
| | - Anna A De Angelis
- Department of Chemistry and Biochemistry, University of California, San Diego La Jolla, San Diego, CA, 92093-0307, USA
| | - Francesca M Marassi
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, San Diego, CA, 92037, USA
| | - Stanley J Opella
- Department of Chemistry and Biochemistry, University of California, San Diego La Jolla, San Diego, CA, 92093-0307, USA.
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Arimont M, Sun SL, Leurs R, Smit M, de Esch IJP, de Graaf C. Structural Analysis of Chemokine Receptor-Ligand Interactions. J Med Chem 2017; 60:4735-4779. [PMID: 28165741 PMCID: PMC5483895 DOI: 10.1021/acs.jmedchem.6b01309] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
This
review focuses on the construction and application of structural chemokine
receptor models for the elucidation of molecular determinants of chemokine
receptor modulation and the structure-based discovery and design of
chemokine receptor ligands. A comparative analysis of ligand binding
pockets in chemokine receptors is presented, including a detailed
description of the CXCR4, CCR2, CCR5, CCR9, and US28 X-ray structures,
and their implication for modeling molecular interactions of chemokine
receptors with small-molecule ligands, peptide ligands, and large
antibodies and chemokines. These studies demonstrate how the integration
of new structural information on chemokine receptors with extensive
structure–activity relationship and site-directed mutagenesis
data facilitates the prediction of the structure of chemokine receptor–ligand
complexes that have not been crystallized. Finally, a review of structure-based
ligand discovery and design studies based on chemokine receptor crystal
structures and homology models illustrates the possibilities and challenges
to find novel ligands for chemokine receptors.
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Affiliation(s)
- Marta Arimont
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Shan-Liang Sun
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Rob Leurs
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Martine Smit
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Iwan J P de Esch
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Chris de Graaf
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam , De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
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Structure of an engineered β-lactamase maltose binding protein fusion protein: insights into heterotropic allosteric regulation. PLoS One 2012; 7:e39168. [PMID: 22720063 PMCID: PMC3375305 DOI: 10.1371/journal.pone.0039168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/16/2012] [Indexed: 11/21/2022] Open
Abstract
Engineering novel allostery into existing proteins is a challenging endeavor to obtain novel sensors, therapeutic proteins, or modulate metabolic and cellular processes. The RG13 protein achieves such allostery by inserting a circularly permuted TEM-1 β-lactamase gene into the maltose binding protein (MBP). RG13 is positively regulated by maltose yet is, serendipitously, inhibited by Zn2+ at low µM concentration. To probe the structure and allostery of RG13, we crystallized RG13 in the presence of mM Zn2+ concentration and determined its structure. The structure reveals that the MBP and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn2+ acts to “twist tie” the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical β3 and β4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn2+ site only slightly affected Zn2+ inhibition 2- to 4-fold. Combined with previous mutagenesis results we therefore hypothesize the presence of two or more inter-domain mutually exclusive inhibitory Zn2+ sites. Mutagenesis and molecular modeling of an intact TEM-1 domain near MBP within the RG13 framework indicated a close surface proximity of the two domains with maltose switching being critically dependent on MBP linker anchoring residues and linker length. Structural analysis indicated that the linker attachment sites on MBP are at a site that, upon maltose binding, harbors both the largest local Cα distance changes and displays surface curvature changes, from concave to relatively flat becoming thus less sterically intrusive. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 β3 linker region via steric and/or linker juxtapositioning mechanisms.
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Poh TY, Pease J, Young JR, Bumstead N, Kaiser P. Re-evaluation of Chicken CXCR1 Determines the True Gene Structure. J Biol Chem 2008; 283:16408-15. [DOI: 10.1074/jbc.m800998200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Gavrilin MA, Gulina IV, Kawano T, Dragan S, Chakravarti L, Kolattukudy PE. Site-directed mutagenesis of CCR2 identified amino acid residues in transmembrane helices 1, 2, and 7 important for MCP-1 binding and biological functions. Biochem Biophys Res Commun 2005; 327:533-40. [PMID: 15629146 DOI: 10.1016/j.bbrc.2004.12.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Indexed: 10/26/2022]
Abstract
Monocyte chemotactic protein-1 (MCP-1) binds its G-protein-coupled seven transmembrane (TM) receptor, CCR2B, and causes infiltration of monocytes/macrophages into areas of injury, infection or inflammation. To identify functionally important amino acid residues in CCR2B, we made specific mutations of nine residues selected on the basis of conservation in chemokine receptors and located TM1 (Tyr(49)), TM2 (Leu(95)), TM3 (Thr(117) and Tyr(120)), and TM7 (Ala(286), Thr(290), Glu(291), and His(297)) and in the extracellular loop 3 (Glu(278)). MCP-1 binding was drastically affected only by mutations in TM7. Reversing the charge at Glu(291) (E291K) and at His(297) (H297D) prevented MCP binding although substitution with Ala at either site had little effect, suggesting that Glu(291) and His(297) probably stabilize TM7 by their ionic interaction. E291A elicited normal Ca(2+) influx. H297A, Y49F in TM1 and L95A in TM2 that showed normal MCP-1 binding did not elicit Ca(2+) influx and elicited no adenylate cyclase inhibition at any MCP-1 concentration. MCP-1 treatment of HEK293 cells caused lamellipodia formation only when they expressed CCR2B. The mutants that showed no Ca(2+) influx and adenylate cyclase inhibition by MCP-1 treatment showed lamellipodia formation and chemotaxis. Our results show that induction of lamellipodia formation, but not Ca(2+) influx and adenylate cyclase inhibition, is necessary for chemotaxis.
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Affiliation(s)
- Mikhail A Gavrilin
- Davis Heart and Lung Reseach Institute, The Ohio State University, Columbus, OH 43210, USA.
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Abstract
Chemotaxis is an important cellular response common in biology. In many chemotaxing cells the signal that regulates movement is initiated by G protein-coupled receptors on the cell surface that bind specific chemoattractants. These receptors share important structural similarities with other G protein-coupled receptors, including rhodopsin, which currently serves as the best starting point for modeling their structures. However, the chemotaxis receptors also share a number of relatively unique structural features that are less common in other GPCRs. The chemoattractant ligands of chemotaxis receptors exhibit a broad variety of sizes and chemical properties, ranging from small molecules and peptides to protein ligands. As a result, different chemotaxis receptors have evolved specialized mechanisms for the early steps of ligand binding and receptor activation. The mechanism of transmembrane signaling is currently under intensive study and several alternate mechanisms proposing different conformational rearrangements of the transmembrane helices have been proposed. Some chemotaxis receptors are proposed to form dimers, and in certain cases dimer formation is proposed to play a role in transmembrane signaling. In principle the structural and dynamical changes that occur during transmembrane signaling could be specialized for different receptors, or could be broadly conserved. Extensive mutagenesis studies have been carried out, and have begun to identify critical residues involved in ligand binding, receptor activation, and transmembrane signaling.
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Affiliation(s)
- Aaron F Miller
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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