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Mollner TA, Giltrap AM, Zeng Y, Demyanenko Y, Buchanan C, Oehlrich D, Baldwin AJ, Anthony DC, Mohammed S, Davis BG. Reductive site-selective atypical C, Z-type/N2-C2 cleavage allows C-terminal protein amidation. SCIENCE ADVANCES 2022; 8:eabl8675. [PMID: 35394836 PMCID: PMC8993120 DOI: 10.1126/sciadv.abl8675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biomolecule environments can enhance chemistries with the potential to mediate and modulate self-modification (e.g., self-cleavage). While these enhanced modes are found in certain biomolecules (e.g., RNA ribozymes), it is more rare in proteins. Targeted proteolytic cleavage is vital to physiology, biotechnology, and even emerging therapy. Yet, purely chemically induced methods for the site-selective cleavage of proteins remain scarce. Here, as a proof of principle, we designed and tested a system intended to combine protein-enhanced chemistry with tag modification to enable synthetic reductive protein chemistries promoted by diboron. This reductively driven, single-electron chemistry now enables an operationally simple, site-selective cleavage protocol for proteins directed to readily accessible dehydroalanine (Dha) residues as tags under aqueous conditions and in cell lysates. In this way, a mild, efficient, enzyme-free method now allows not only precise chemical proteolysis but also simultaneous use in the removal of affinity tags and/or protein-terminus editing to create altered N- and C-termini such as protein amidation (─CONH2).
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Affiliation(s)
- Tim A. Mollner
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | | | - Yibo Zeng
- The Rosalind Franklin Institute, Oxfordshire, UK
| | | | - Charles Buchanan
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Daniel Oehlrich
- Global Medicinal Chemistry, Janssen Research & Development, Beerse, Belgium
| | - Andrew J. Baldwin
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
| | | | - Shabaz Mohammed
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Benjamin G. Davis
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
- Corresponding author.
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2
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Quanten T, Savić ND, Parac-Vogt TN. Hydrolysis of Peptide Bonds in Protein Micelles Promoted by a Zirconium(IV)-Substituted Polyoxometalate as an Artificial Protease. Chemistry 2020; 26:11170-11179. [PMID: 32515831 DOI: 10.1002/chem.202001920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Indexed: 12/22/2022]
Abstract
The development of artificial proteases is challenging, but important for many applications in modern proteomics and biotechnology. The hydrolysis of hydrophobic or unstructured proteins is particularly difficult due to their poor solubility, which often requires the presence of surfactants. Herein, it is shown that a zirconium(IV)-substituted Keggin polyoxometalate (POM), (Et2 NH2 )10 [Zr(α-PW11 O39 )2 ] (1), is able to selectively hydrolyze β-casein, which is an intrinsically unstructured protein at pH 7.4 and 60 °C. Four surfactants (sodium dodecyl sulfate (SDS), N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (ZW3-12), 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and polyethylene glycol tert-octylphenyl ether (TX-100)), which differ in the nature of their polar groups, were investigated for their role in influencing the selectivity and efficiency of protein hydrolysis. Under experimental conditions, β-casein forms micellar structures in which the hydrophilic part of the protein is water accessible and able to interact with 1. Identical fragmentation patterns of β-casein in the presence of 1 were observed through SDS poly(acrylamide) gel electrophoresis both in the presence and absence of surfactants, but the rate of hydrolysis varied, depending on the nature of surfactant. Whereas TX-100 surfactant, which has a neutral polar head, caused only a slight decrease in the hydrolysis rate, stronger inhibition was observed in the presence surfactants with charges in their polar heads (CHAPS, ZW3-12, SDS). These results were consistent with those of tryptophan fluorescencequenching studies, which showed that the binding between β-casein and 1 decreased with increasing repulsion between the POM and the polar heads of the surfactants. In all cases, the micellar structure of β-casein was not significantly affected by the presence of POM or surfactants, as indicated by circular dichroism spectroscopy.
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Affiliation(s)
- Thomas Quanten
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Box 2404, 3001, Leuven, Belgium
| | - Nada D Savić
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Box 2404, 3001, Leuven, Belgium
| | - Tatjana N Parac-Vogt
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Box 2404, 3001, Leuven, Belgium
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3
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A versatile method for producing labeled or unlabeled Aβ55, Aβ40, and other β-amyloid family peptides. Protein Expr Purif 2019; 162:72-82. [DOI: 10.1016/j.pep.2019.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/12/2019] [Accepted: 04/19/2019] [Indexed: 12/18/2022]
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4
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Li Q, Montalban-Lopez M, Kuipers OP. Feasability of Introducing a Thioether Ring in Vasopressin by nisBTC Co-expression in Lactococcus lactis. Front Microbiol 2019; 10:1508. [PMID: 31333616 PMCID: PMC6614560 DOI: 10.3389/fmicb.2019.01508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 06/17/2019] [Indexed: 11/13/2022] Open
Abstract
Introducing one or more intramolecular thioether bridges in a peptide provides a promising approach to create more stable molecules with improved pharmacodynamic properties and especially to protect peptides against proteolytic degradation. Lanthipeptides are compounds that naturally possess thioether bonds in their structure. The model lanthipeptide, nisin, is produced by Lactococcus lactis as a core peptide fused to a leader peptide. The modification machinery responsible for nisin production, including the Ser/Thr-dehydratase NisB and the cyclase NisC, can be applied for introducing a thioether bridge into peptides fused to the nisin leader peptide, e.g., to replace a disulfide bond. Vasopressin plays a key role in water homeostasis in the human body and helps to constrict blood vessels. There are two cysteine residues in the structure of wild type vasopressin, which form a disulfide bridge in the mature peptide. Here, we show it is possible to direct the biosynthesis of vasopressin variants in such a way that the disulfide bridge is replaced by a thioether bridge using the nisin modification machinery NisBTC, albeit at low efficiency. Vasopressin mutants were fused either to the nisin leader peptide directly (Type A), after the first three rings of nisin (Type B/C), or after full nisin (Type D). The type B strategy was optimal for expression. LC-MS/MS data verified the formation of a thioether bridge, which provides proof of principle for this modification in vasopressin. This is a first step prior to the necessary increase of the production yield and further purification of these peptides to finally test their biological activity in tissue and animal models.
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Affiliation(s)
- Qian Li
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Manuel Montalban-Lopez
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.,Department of Microbiology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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5
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Liutkus M, Fraser SA, Caron K, Stigers DJ, Easton CJ. Peptide Synthesis through Cell-Free Expression of Fusion Proteins Incorporating Modified Amino Acids as Latent Cleavage Sites for Peptide Release. Chembiochem 2016; 17:908-12. [PMID: 26918308 DOI: 10.1002/cbic.201600091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Indexed: 01/03/2023]
Abstract
Chlorinated analogues of Leu and Ile are incorporated during cell-free expression of peptides fused to protein, by exploiting the promiscuity of the natural biosynthetic machinery. They then act as sites for clean and efficient release of the peptides simply by brief heat treatment. Dehydro analogues of Leu and Ile are similarly incorporated as latent sites for peptide release through treatment with iodine under cold conditions. These protocols complement enzyme-catalyzed methods and have been used to prepare calcitonin, gastrin-releasing peptide, cholecystokinin-7, and prolactin-releasing peptide prohormones, as well as analogues substituted with unusual amino acids, thus illustrating their practical utility as alternatives to more traditional chemical peptide synthesis.
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Affiliation(s)
- Mantas Liutkus
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Samuel A Fraser
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Karine Caron
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Dannon J Stigers
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Christopher J Easton
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
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6
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Hwang PM, Pan JS, Sykes BD. Targeted expression, purification, and cleavage of fusion proteins from inclusion bodies in Escherichia coli. FEBS Lett 2013; 588:247-52. [PMID: 24076468 DOI: 10.1016/j.febslet.2013.09.028] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 09/20/2013] [Indexed: 01/24/2023]
Abstract
Today, proteins are typically overexpressed using solubility-enhancing fusion tags that allow for affinity chromatographic purification and subsequent removal by site-specific protease cleavage. In this review, we present an alternative approach to protein production using fusion partners specifically designed to accumulate in insoluble inclusion bodies. The strategy is appropriate for the mass production of short peptides, intrinsically disordered proteins, and proteins that can be efficiently refolded in vitro. There are many fusion protein systems now available for insoluble expression: TrpLE, ketosteroid isomerase, PurF, and PagP, for example. The ideal fusion partner is effective at directing a wide variety of target proteins into inclusion bodies, accumulates in large quantities in a highly pure form, and is readily solubilized and purified in commonly used denaturants. Fusion partner removal under denaturing conditions is biochemically challenging, requiring harsh conditions (e.g., cyanogen bromide in 70% formic acid) that can result in unwanted protein modifications. Recent advances in metal ion-catalyzed peptide bond cleavage allow for more mild conditions, and some methods involving nickel or palladium will likely soon appear in more biological applications.
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Affiliation(s)
- Peter M Hwang
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada; Division of General Internal Medicine, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
| | - Jonathan S Pan
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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7
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Grozav AG, Willard BB, Kozuki T, Chikamori K, Micluta MA, Petrescu AJ, Kinter M, Ganapathi R, Ganapathi MK. Tyrosine 656 in topoisomerase IIβ is important for the catalytic activity of the enzyme: Identification based on artifactual +80-Da modification at this site. Proteomics 2011; 11:829-42. [PMID: 21280220 DOI: 10.1002/pmic.201000194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 09/01/2010] [Accepted: 11/25/2010] [Indexed: 12/11/2022]
Abstract
Topoisomerase (topo) II catalyzes topological changes in DNA. Although both human isozymes, topo IIα and β are phosphorylated, site-specific phosphorylation of topo IIβ is poorly characterized. Using LC-MS/MS analysis of topo IIβ, cleaved with trypsin, Arg C or cyanogen bromide (CNBr) plus trypsin, we detected four +80-Da modified sites: tyr656, ser1395, thr1426 and ser1545. Phosphorylation at ser1395, thr1426 and ser1545 was established based on neutral loss of H(3) PO(4) (-98 Da) in the CID spectra and on differences in 2-D-phosphopeptide maps of (32) P-labeled wild-type (WT) and S1395A or T1426A/S1545A mutant topo IIβ. However, phosphorylation at tyr656 could not be verified by 2-D-phosphopeptide mapping of (32) P-labeled WT and Y656F mutant protein or by Western blotting with phosphotyrosine-specific antibodies. Since the +80-Da modification on tyr656 was observed exclusively during cleavage with CNBr and trypsin, this modification likely represented bromination, which occurred during CNBr cleavage. Re-evaluation of the CID spectra identified +78/+80-Da fragment ions in CID spectra of two peptides containing tyr656 and tyr711, confirming bromination. Interestingly, mutation of only tyr656, but not ser1395, thr1326 or ser1545, decreased topo IIβ activity, suggesting a functional role for tyr656. These results, while identifying an important tyrosine in topo IIβ, underscore the importance of careful interpretation of modifications having the same nominal mass.
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Affiliation(s)
- Adrian G Grozav
- Clinical Pharmacology Program, Taussig Cancer Institute, Cleveland, OH, USA
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8
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Lopez KM, Greenaway FT. Identification of the copper-binding ligands of lysyl oxidase. J Neural Transm (Vienna) 2010; 118:1101-9. [DOI: 10.1007/s00702-010-0559-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 12/08/2010] [Indexed: 11/24/2022]
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9
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Identification of the disulfide bonds of lysyl oxidase. J Neural Transm (Vienna) 2010; 118:1111-4. [DOI: 10.1007/s00702-010-0560-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 12/08/2010] [Indexed: 11/26/2022]
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10
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Meyer B, Papasotiriou DG, Karas M. 100% protein sequence coverage: a modern form of surrealism in proteomics. Amino Acids 2010; 41:291-310. [DOI: 10.1007/s00726-010-0680-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 06/25/2010] [Indexed: 01/11/2023]
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11
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Radha C, Prakash V. Structural and Functional Properties of Heat-processed Soybean Flour: Effect of Proteolytic Modification. FOOD SCI TECHNOL INT 2010. [DOI: 10.1177/1082013209350347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Heat processing of soybeans alters its structural behavior, solubility, and in turn the functional properties. Heat-processed soy flour was prepared by autoclaving the defatted soy flour at 121 °C at 15 psi. The effect of enzymatic modification on the structural changes and functional properties of heat-processed soy flour was investigated. The combination of heat processing and enzymatic modification was carried out in two ways: (1) enzymatic modification followed by autoclaving and (2) autoclaving followed by enzymatic modification. Defatted soy flour (control), autoclaved soy flour, enzyme-modified flour, enzyme-modified and then autoclaved flour, autoclaved and then enzyme-modified flour were analyzed for physico-chemical and functional properties. Molecular weight profile of the protein was altered depending on the nature of treatments. Structural studies showed that enzymatic modification gave a porous type morphology to the particles. Enzymatic modification of autoclaved soy flour increased its surface hydrophobicity to 3136±400 units from 600±100 units of autoclaved soy flour. The results indicated that enzymatic modification of autoclaved soy flour increased its acid solubility (pH 4—4.5) from 17% to 56% over a control value of 24%. The foaming capacity of the enzyme-modified and then autoclaved soy flour was 80% while that of the autoclaved and then enzyme-modified flour was 42%. The soy flour that was autoclaved and then enzyme modified showed better emulsifying properties (174 mL oil/g flour) than the flour that was enzyme-modified and then autoclaved. The modified soy flour based on its functional and physico-chemical properties should find application in many food systems.
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Affiliation(s)
- C. Radha
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute (A constituent Laboratory of CSIR) Mysore 570 020, India
| | - V. Prakash
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute (A constituent Laboratory of CSIR) Mysore 570 020, India,
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12
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Control of the transcription of a short gene encoding a cyclic peptide in Streptococcus thermophilus: a new quorum-sensing system? J Bacteriol 2007; 189:8844-54. [PMID: 17921293 DOI: 10.1128/jb.01057-07] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-positive bacteria secrete a variety of peptides that are often subjected to posttranslational modifications and that are either antimicrobials or pheromones involved in bacterial communication. Our objective was to identify peptides secreted by Streptococcus thermophilus, a nonpathogenic bacterium widely used in dairy technology in association with other bacteria, and to understand their potential roles in cell-cell communication. Using reverse-phase liquid chromatography, mass spectrometry, and Edman sequencing, we analyzed the culture supernatants of three S. thermophilus strains (CNRZ1066, LMG18311, and LMD-9) grown in a medium containing no peptides. We identified several peptides in the culture supernatants, some of them found with the three strains while others were specific to the LMD-9 strain. We focused our study on a new modified peptide secreted by S. thermophilus LMD-9 and designated Pep1357C. This peptide contains 9 amino acids and lost 2 Da in a posttranslational modification, most probably a dehydrogenation, leading to a linkage between the Lys2 and Trp6 residues. Production of Pep1357C and transcription of its encoding gene depend on both the medium composition and the growth phase. Furthermore, we demonstrated that transcription of the gene coding for Pep1357C is drastically decreased in mutants inactivated for the synthesis of a short hydrophobic peptide, a transcriptional regulator, or the oligopeptide transport system. Taken together, our results led us to deduce that the transcription of the Pep1357C-encoding gene is controlled by a new quorum-sensing system.
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13
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Kibbey MM, Jameson MJ, Eaton EM, Rosenzweig SA. Insulin-like growth factor binding protein-2: contributions of the C-terminal domain to insulin-like growth factor-1 binding. Mol Pharmacol 2005; 69:833-45. [PMID: 16306230 DOI: 10.1124/mol.105.016998] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Signaling by the insulin-like growth factor (IGF)-1 receptor (IGF-1R) has been implicated in the promotion and aggressiveness of breast, prostate, colorectal, and lung cancers. The IGF binding proteins (IGFBPs) represent a class of natural IGF antagonists that bind to and sequester IGF-1/2 from the IGF-1R, making them attractive candidates as therapeutics for cancer prevention and control. Recombinant human IGFBP-2 significantly attenuated IGF-1-stimulated MCF-7 cell proliferation with coaddition of 20 or 100 nM IGFBP-2 (50 or 80% inhibition, respectively). We previously identified IGF-1 contact sites both upstream and downstream of the CWCV motif (residues 247-250) in human IGFBP-2 (J Biol Chem 276:2880-2889, 2001). To further test their contributions to IGFBP-2 function, the single tryptophan in human IGFBP-2, Trp-248, was selectively cleaved with 2-(2'nitrophenylsulfenyl)-3-methyl-3 bromoindolenine (BNPS-skatole) and the BNPS-skatole products IGFBP-2(1-248) and IGFBP-2(249-289) as well as IGFBP-2(1-190) were expressed as glutathione S-transferase-fusion proteins and purified. Based on competition binding analysis, deletion of residues 249 to 289 caused an approximately 20-fold decrease in IGF-1 binding affinity (IGFBP-2 EC50 = 0.35 nM and IGFBP-2(1-248) = 7 nM). Removal of the remainder of the C-terminal domain had no further effect on affinity (IGFBP-2(1-190) EC50 = 9.2 nM). In kinetic assays, IGFBP-2(1-248) and IGFBP-2(1-190) exhibited more rapid association and dissociation rates than full-length IGFBP-2. These results confirm that regions upstream and downstream of the CWCV motif participate in IGF-1 binding. They further support the development of full-length IGFBP-2 as a cancer therapeutic.
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Affiliation(s)
- Megan M Kibbey
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA
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14
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Kamal N, Chowdhury S, Madan T, Sharma D, Attreyi M, Haq W, Katti SB, Kumar A, Sarma PU. Tryptophan residue is essential for immunoreactivity of a diagnostically relevant peptide epitope of A. fumigatus. Mol Cell Biochem 2005; 275:223-31. [PMID: 16335802 DOI: 10.1007/s11010-005-2056-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The role of tryptophan (Trp17) in immunoreactivity of P1, the diagnostically relevant peptide from a major allergen/antigen of Aspergillus fumigatus, was evaluated by chemically modifying tryptophanyl residue of P1. In BIAcore kinetic studies, unmodified P1 showed a 100-fold higher binding with ABPA (Allergic Bronchopulmonary Aspergillosis) patients' IgG [KD (equilibrium dissociation constant) = 2.74 e(-8) +/- 0.13 M] than the controls' IgG (KD = 2.97 e(-6) +/- 0.14 M), whereas chemically-modified P1 showed similar binding [KD patients' IgG = 3.25 e(-7) +/- 0.16 M, KD controls' IgG = 3.86 e(-7) +/- 0.19 M] indicating loss of specific immunoreactivity of P1 on tryptophan modification. Modified P1 showed loss of specific binding to IgE and IgG antibodies of ABPA patients in ELISA (Enzyme-Linked Immunosorbent Assay). The study infers that tryptophan residue (Trp17) is essential for immunoreactivity of P1.
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Affiliation(s)
- Neel Kamal
- Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
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15
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Crimmins DL, Mische SM, Denslow ND. Chemical cleavage of proteins in solution. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2005; Chapter 11:11.4.1-11.4.11. [PMID: 18429274 DOI: 10.1002/0471140864.ps1104s40] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Described in this unit are five basic protocols that are widely used for specific and efficient chemical cleavage of proteins in solution. Cyanogen bromide (CNBr) cleaves at methionine (Met) residues; BNPS-skatole cleaves at tryptophan (Trp) residues; formic acid cleaves at aspartic acid-proline (Asp-Pro) peptide bonds; hydroxylamine cleaves at asparagine-glycine (Asn-Gly) peptide bonds, and 2-nitro-5-thiocyanobenzoic acid (NTCB) cleaves at cysteine (Cys) residues. Because the above loci are at relatively low abundance in most proteins, digestion with these agents will yield relatively long peptides.
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Affiliation(s)
- Dan L Crimmins
- Washington University School of Medicine, St. Louis, Missouri
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16
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Reyes-López CA, Hernández-Santoyo A, Pedraza-Escalona M, Mendoza G, Hernández-Arana A, Rodríguez-Romero A. Insights into a conformational epitope of Hev b 6.02 (hevein). Biochem Biophys Res Commun 2004; 314:123-30. [PMID: 14715255 DOI: 10.1016/j.bbrc.2003.12.068] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Hevein (Hev b 6.02) is a major IgE-binding allergen in natural rubber latex and manufactured products. Both tryptophans (Trp(21) and Trp(23)) of the hevein molecule were chemically modified with BNPS-skatole (2-nitrophenylsulfenyl-3-methyl-3(')-bromoindolenine); derivatized allergen failed to significantly inhibit binding of serum IgE in ELISA assays. Similarly, skin prick tests showed that hevein-positive patients gave no response with the modified allergen. Dot blot experiments carried out with anti-hevein mono- and polyclonal antibodies confirmed the importance of Trp(21) and Trp(23) for antibody-recognition, and demonstrated the specific cross-reactivity of other molecules containing hevein-like domains. We also report the structure of Hev b 6.02 at an extended resolution (1.5A) and compare its surface properties around Trp residues with those of similar regions in other allergens. Overall our results indicate that the central part of the protein, which comprises three aromatic and other acidic and polar residues, constitutes a conformational epitope.
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Affiliation(s)
- César A Reyes-López
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510, Coyoacán México, DF, Mexico
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17
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Sass E, Blachinsky E, Karniely S, Pines O. Mitochondrial and cytosolic isoforms of yeast fumarase are derivatives of a single translation product and have identical amino termini. J Biol Chem 2001; 276:46111-7. [PMID: 11585823 DOI: 10.1074/jbc.m106061200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously proposed that a single translation product of the FUM1 gene encoding fumarase is distributed between the cytosol and mitochondria of Saccharomyces cerevisiae and that all fumarase translation products are targeted and processed in mitochondria before distribution. Alternative models for fumarase distribution have been proposed that require more than one translation product. In the current work (i) we show by using sequential Edman degradation and mass spectrometry that fumarase cytosolic and mitochondrial isoenzymes have an identical amino terminus that is formed by cleavage by the mitochondrial processing peptidase, (ii) we have generated fumarase mutants in which the second potential translation initiation codon (Met-24) has been substituted, yet the protein is processed efficiently and retains its ability to be distributed between the cytosol and mitochondria, and (iii) we show that although a signal peptide is required for fumarase targeting to mitochondria the specific fumarase signal peptide and the sequence immediately downstream to the cleavage site are not required for the dual distribution phenomenon. Our results are discussed in light of our model of fumarase targeting and distribution that suggests rapid folding into an import-incompetent state and retrograde movement of the processed protein back to the cytosol through the translocation pore.
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Affiliation(s)
- E Sass
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem 91120, Israel
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18
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Chong JM, Speicher DW. Determination of disulfide bond assignments and N-glycosylation sites of the human gastrointestinal carcinoma antigen GA733-2 (CO17-1A, EGP, KS1-4, KSA, and Ep-CAM). J Biol Chem 2001; 276:5804-13. [PMID: 11080501 DOI: 10.1074/jbc.m008839200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The GA733-2 antigen is a cell surface glycoprotein highly expressed on most human gastrointestinal carcinoma and at a lower level on most normal epithelia. It is an unusual cell-cell adhesion protein that does not exhibit any obvious relationship to the four known classes of adhesion molecules. In this study, the disulfide-bonding pattern of the GA733-2 antigen was determined using matrix-assisted laser desorption/ionization mass spectrometry and N-terminal sequencing of purified tryptic peptides treated with 2-[2'-nitrophenylsulfonyl]-3-methyl-3-bromoindolenine or partially reduced and alkylated. Numbering GA733-2 cysteines sequentially from the N terminus, the first three disulfide linkages are Cys1-Cys4, Cys2-Cys6, and Cys3-Cys5, which is a novel pattern for a cysteine-rich domain instead of the expected epidermal growth factor-like disulfide structure. The next three disulfide linkages are Cys7-Cys8, Cys9-Cys10, and Cys11-Cys12, consistent with the recently determined disulfide pattern of the thyroglobulin type 1A domain of insulin-like growth factor-binding proteins 1 and 6. Analysis of glycosylation sites showed that GA733-2 antigen contained N-linked carbohydrate but that no O-linked carbohydrate groups were detected. Of the three potential N-linked glycosylation sites, Asn175 was not glycosylated, whereas Asn88 was completely glycosylated, and Asn51 was partially glycosylated. These data show that the extracellular domain of the GA733-2 antigen consists of three distinct domains; a novel cysteine-rich N-terminal domain (GA733 type 1 motif), a cysteine-rich thyroglobulin type 1A domain (GA733 type 2 motif), and a unique nonglycosylated domain without cysteines (GA733 type 3 motif).
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Affiliation(s)
- J M Chong
- Wistar Institute, Philadelphia, Pennsylvania 19104, USA
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