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Zhang B, Gao H, Gong Z, Zhao L, Zhong B, Sui Z, Liang Z, Zhang Y, Zhao Q, Zhang L. Improved Cross-Linking Coverage for Protein Complexes Containing Low Levels of Lysine by Using an Enrichable Photo-Cross-Linker. Anal Chem 2023. [PMID: 37303169 DOI: 10.1021/acs.analchem.2c05020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chemical cross-linking coupled with mass spectrometry (XL-MS) is an important technique for the structural analysis of protein complexes where the coverage of amino acids and the identification of cross-linked sites are crucial. Photo-cross-linking has multisite reactivity and is valuable for the structural analysis of chemical cross-linking. However, a high degree of heterogeneity results from this multisite reactivity, which results in samples with higher complexity and lower abundance. Additionally, the applicability of photo-cross-linking is limited to purified protein complexes. In this work, we demonstrate a photo-cross-linker, alkynyl-succinimidyl-diazirine (ASD) with the reactive groups of N-hydroxysuccinimide ester and diazirine, as well as the click-enrichable alkyne group. Photo-cross-linkers can provide higher site reactivity for proteins that contain only a small number of lysine residues, thereby complementing the more commonly used lysine-targeting cross-linkers. By systematically analyzing proteins with differing lysine contents and differing flexibilities, we demonstrated clear enhancement in structure elucidation for proteins containing less lysine and with high flexibility. In addition, enrichment approaches of alkynyl-azide click chemistry conjugated with biotin-streptavidin purification (coinciding with parallel orthogonal digestion) improved the identification coverage of cross-links. We show that this photo-cross-linking approach can be used for membrane proteome-wide complex analysis. This method led to the identification of a total of 14066 lysine-X cross-linked site pairs from a total of 2784 proteins. Thus, this cross-linker is a valuable addition to a photo-cross-linking toolkit and improves the identification coverage of XL-MS in functional structure analysis.
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Affiliation(s)
- Beirong Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hang Gao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhou Gong
- CAS Innovation Academy for Precision Measurement Science and Technology, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Chinese Academy of Sciences, Wuhan, Hubei 430071, People's Republic of China
| | - Lili Zhao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bowen Zhong
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
| | - Zhigang Sui
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
| | - Zhen Liang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
| | - Yukui Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
| | - Qun Zhao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
| | - Lihua Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of China
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The Interplay between S-Glutathionylation and Phosphorylation of Cardiac Troponin I and Myosin Binding Protein C in End-Stage Human Failing Hearts. Antioxidants (Basel) 2021; 10:antiox10071134. [PMID: 34356367 PMCID: PMC8301081 DOI: 10.3390/antiox10071134] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 12/24/2022] Open
Abstract
Oxidative stress is defined as an imbalance between the antioxidant defense system and the production of reactive oxygen species (ROS). At low levels, ROS are involved in the regulation of redox signaling for cell protection. However, upon chronical increase in oxidative stress, cell damage occurs, due to protein, DNA and lipid oxidation. Here, we investigated the oxidative modifications of myofilament proteins, and their role in modulating cardiomyocyte function in end-stage human failing hearts. We found altered maximum Ca2+-activated tension and Ca2+ sensitivity of force production of skinned single cardiomyocytes in end-stage human failing hearts compared to non-failing hearts, which was corrected upon treatment with reduced glutathione enzyme. This was accompanied by the increased oxidation of troponin I and myosin binding protein C, and decreased levels of protein kinases A (PKA)- and C (PKC)-mediated phosphorylation of both proteins. The Ca2+ sensitivity and maximal tension correlated strongly with the myofilament oxidation levels, hypo-phosphorylation, and oxidative stress parameters that were measured in all the samples. Furthermore, we detected elevated titin-based myocardial stiffness in HF myocytes, which was reversed by PKA and reduced glutathione enzyme treatment. Finally, many oxidative stress and inflammation parameters were significantly elevated in failing hearts compared to non-failing hearts, and corrected upon treatment with the anti-oxidant GSH enzyme. Here, we provide evidence that the altered mechanical properties of failing human cardiomyocytes are partially due to phosphorylation, S-glutathionylation, and the interplay between the two post-translational modifications, which contribute to the development of heart failure.
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Breitkreuz M, Hamdani N. A change of heart: oxidative stress in governing muscle function? Biophys Rev 2015; 7:321-341. [PMID: 28510229 DOI: 10.1007/s12551-015-0175-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/08/2015] [Indexed: 02/07/2023] Open
Abstract
Redox/cysteine modification of proteins that regulate calcium cycling can affect contraction in striated muscles. Understanding the nature of these modifications would present the possibility of enhancing cardiac function through reversible cysteine modification of proteins, with potential therapeutic value in heart failure with diastolic dysfunction. Both heart failure and muscular dystrophy are characterized by abnormal redox balance and nitrosative stress. Recent evidence supports the synergistic role of oxidative stress and inflammation in the progression of heart failure with preserved ejection fraction, in concert with endothelial dysfunction and impaired nitric oxide-cyclic guanosine monophosphate-protein kinase G signalling via modification of the giant protein titin. Although antioxidant therapeutics in heart failure with diastolic dysfunction have no marked beneficial effects on the outcome of patients, it, however, remains critical to the understanding of the complex interactions of oxidative/nitrosative stress with pro-inflammatory mechanisms, metabolic dysfunction, and the redox modification of proteins characteristic of heart failure. These may highlight novel approaches to therapeutic strategies for heart failure with diastolic dysfunction. In this review, we provide an overview of oxidative stress and its effects on pathophysiological pathways. We describe the molecular mechanisms driving oxidative modification of proteins and subsequent effects on contractile function, and, finally, we discuss potential therapeutic opportunities for heart failure with diastolic dysfunction.
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Affiliation(s)
- Martin Breitkreuz
- Department of Cardiovascular Physiology, Ruhr University Bochum, MA 3/56, 44780, Bochum, Germany
| | - Nazha Hamdani
- Department of Cardiovascular Physiology, Ruhr University Bochum, MA 3/56, 44780, Bochum, Germany.
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Brodie NI, Makepeace KAT, Petrotchenko EV, Borchers CH. Isotopically-coded short-range hetero-bifunctional photo-reactive crosslinkers for studying protein structure. J Proteomics 2014; 118:12-20. [PMID: 25192908 DOI: 10.1016/j.jprot.2014.08.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 08/19/2014] [Accepted: 08/23/2014] [Indexed: 12/20/2022]
Abstract
UNLABELLED The resolution and the fidelity of a protein structural model, constructed using crosslinking data, is dependent on the crosslinking distance constraints. Most of the popular amine-reactive NHS-ester crosslinkers are limited in their capacity to provide short distance constraints because of the rarity of lysine residues occurring in close proximity in the protein structure. To solve this problem, hetero-bifunctional crosslinkers containing both a photo-reactive functional group and an NHS-ester group can be used to enable non-specific crosslinking within the proximity of these lysine residues. Here we develop three such isotopically-coded hetero-bifunctional photo-reactive crosslinkers, bearing azido, diazirine or benzophenone photo-reactive groups (azido-benzoic-acid-succinimide (ABAS)-(12)C6/(13)C6, succinimidyl-diazirine (SDA)-(12)C5/(13)C5, and carboxy-benzophenone-succinimide (CBS)-(12)C6/(13)C6, respectively). These crosslinkers were validated using several model proteins/peptides and were then applied to study the structure of the native α-synuclein protein. In that case the ABAS crosslinker proved to be the most suitable, with 10 crosslinks being found in the native α-synuclein structure. BIOLOGICAL SIGNIFICANCE Structural proteomics can be used for studying protein structures which may be difficult to examine by traditional structural biology methods such as NMR or X-ray crystallography. Crosslinking in particular is used to provide distance constraints for molecular modeling of individual proteins and protein complexes. The shortest distance constraints are most valuable for the modeling process. To be able to provide such short distance constraints, non-specific photo-reactive chemistry can be used for crosslinking reactions. However, detection of such non-specific crosslinks is difficult because the signal from any particular crosslink is low due to the broad reactivity of the crosslinking reagents. To overcome this problem, we have employed isotopic labeling of these crosslinkers. In this paper, we have demonstrated their effectiveness for studying the native α-synuclein protein structure. The non-specific reactivity, in combination with isotopic coding of these crosslinkers, allowed for the formation and detection of short-range crosslinks, targeting a variety of amino acids. These reagents may prove useful for future applications to a variety of protein structural problems. This article is part of a Special Issue entitled: Protein dynamics in health and disease. Guest Editors: Pierre Thibault and Anne-Claude Gingras.
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Affiliation(s)
- Nicholas I Brodie
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria V8Z7X8, Canada
| | - Karl A T Makepeace
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria V8Z7X8, Canada
| | - Evgeniy V Petrotchenko
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria V8Z7X8, Canada
| | - Christoph H Borchers
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria V8Z7X8, Canada; Department of Biochemistry & Microbiology, University of Victoria, Petch Building Room 207, 3800 Finnerty Rd., Victoria, BC V8P 5C2, Canada.
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Vivero-Escoto JL, Rieter WJ, Lau H, Huxford-Phillips RC, Lin W. Biodegradable polysilsesquioxane nanoparticles as efficient contrast agents for magnetic resonance imaging. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:3523-31. [PMID: 23613450 PMCID: PMC3804422 DOI: 10.1002/smll.201300198] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 03/11/2013] [Indexed: 05/20/2023]
Abstract
Polysilsesquioxane (PSQ) nanoparticles are crosslinked homopolymers formed by condensation of functionalized trialkoxysilanes, and provide an interesting platform for developing biologically and biomedically relevant nanomaterials. In this work, the design and synthesis of biodegradable PSQ particles with extremely high payloads of paramagnetic Gd(III) centers is explored, for use as efficient contrast agents for magnetic resonance imaging (MRI). Two new bis(trialkoxysilyl) derivatives of Gd(III) diethylenetriamine pentaacetate (Gd-DTPA) containing disulfide linkages are synthesized and used to form biodegradable Gd-PSQ particles by base-catalyzed condensation reactions in reverse microemulsions. The Gd-PSQ particles, PSQ-1 and PSQ-2, carry 53.8 wt% and 49.3 wt% of Gd-DTPA derivatives, respectively. In addition, the surface carboxy groups on the PSQ-2 particles can be modified with polyethylene glycol (PEG) and the anisamide (AA) ligand to enhance biocompatibility and cell uptake, respectively. The Gd-PSQ particles are readily degradable to release the constituent Gd(III) chelates in the presence of endogenous reducing agents such as cysteine and glutathione. The MR relaxivities of the Gd-PSQ particles are determined using a 3T MR scanner, with r1 values ranging from 5.9 to 17.8 mMs(-1) on a per-Gd basis. Finally, the high sensitivity of the Gd-PSQ particles as T1 -weighted MR contrast agents is demonstrated with in vitro MR imaging of human lung and pancreatic cancer cells. The enhanced efficiency of the anisamide-functionalized PSQ-2 particles as a contrast agent is corroborated by both confocal laser scanning microscopy imaging and ICP-MS analysis of Gd content in vitro.
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Vivero-Escoto JL, Taylor-Pashow KML, Huxford RC, Rocca JD, Okoruwa C, An H, Lin W, Lin W. Multifunctional mesoporous silica nanospheres with cleavable Gd(III) chelates as MRI contrast agents: synthesis, characterization, target-specificity, and renal clearance. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:3519-28. [PMID: 22069305 PMCID: PMC4040274 DOI: 10.1002/smll.201100521] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 05/31/2011] [Indexed: 05/17/2023]
Abstract
Mesoporous silica nanospheres (MSNs) are a promising material for magnetic resonance imaging (MRI) contrast agents. In this paper multifunctional MSNs with cleavable Gd(III) chelates are synthesized and characterized, and their applicability as MRI contrast agents is demonstrated both in vitro and in vivo. The MSNs contain Gd(III) chelates that are covalently linked via a redox-responsive disulfide moiety. The MSNs are further functionalized with polyethylene glycol (PEG) and an anisamide ligand to improve their biocompatibility and target specificity. The effectiveness of MSNs as an MRI imaging contrast agent and their targeting ability are successfully demonstrated in vitro using human colon adenocarcinoma and pancreatic cancer cells. Finally, the capability of this platform as an in vivo MRI contrast agent is tested using a 3T scanner. The Gd(III) chelate was quickly cleaved by the blood pool thiols and eliminated through the renal excretion pathway. Further tuning of the Gd(III) chelate release kinetics is needed before the MSN system can be used as target-specific MRI contrast agents in vivo.
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Affiliation(s)
- Juan L. Vivero-Escoto
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | | | - Rachel C. Huxford
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Joseph Della Rocca
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Christie Okoruwa
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Hongyu An
- Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Weili Lin
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Wenbin Lin
- Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
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Persinger J, Bartholomew B. Mapping the contacts of yeast TFIIIB and RNA polymerase III at various distances from the major groove of DNA by DNA photoaffinity labeling. J Biol Chem 1996; 271:33039-46. [PMID: 8955150 DOI: 10.1074/jbc.271.51.33039] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The structure of the Saccharomyces cerevisiae RNA polymerase III transcription complex on the SUP4 tRNATyr gene was probed at distances of approximately 10 to approximately 23 A from the C-5 methyl of thymidine in the major groove of DNA using photoreactive aryl azides attached to deoxyuridine by variable chain lengths. The nucleotide analogs contained an azidobenzoyl group attached with chain lengths that were incrementally increased by approximately 4. 3 A by inserting 1-3 glycine residues into the chain. Another photoreactive deoxyuridine analog was made that contained a butyl chain (ABU-dUMP) to assess the effect of the chain's hydrophobicity on its ability to photoaffinity label the transcription complex. These nucleotide analogs were incorporated at base pairs (bp) -26/-21, -17, or -3/-2 on the nontranscribed strand of the SUP4 tRNATyr gene along with an [alpha-32P]dNMP by primer extension using an immobilized single-stranded DNA template annealed to specific oligonucleotides. The 27-kDa subunit of TFIIIB or the TATA box binding protein was photoaffinity labeled at bp -26/-21 with nucleotide analogs containing a approximately 19- or approximately 23-A chain and not with shorter chains of approximately 10 to approximately 15 A in length. The B" subunit of TFIIIB (Mr = 90 kDa) was photoaffinity labeled at bps -26/-21 with DNA containing a approximately 14-A chain and not with shorter or longer chains. Cross-linking of the B" subunit was inhibited by binding of RNA polymerase III (Pol III) to the TFIIIB-DNA complex and suggested that Pol III binding causes a conformational change in the TFIIIB-DNA complex resulting in the displacement of the 90-kDa subunit at bps -26/-21. Next, the chain length dependence of photoaffinity labeling the 34-kDa subunit of Pol III at bps -17 and -3/-2 indicated that the 34-kDa subunit of Pol III is slightly removed from the major groove at bp -17 in the initiation complex and makes closer contact at bps -3/-2 in a stalled elongation complex.
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Affiliation(s)
- J Persinger
- Department of Medical Biochemistry, School of Medicine, Southern Illinois University at Carbondale, Carbondale, Illinois 62901-4413, USA
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Hanson M, Unger KK, Mant CT, Hodges RS. Polymer-coated reversed-phase packings with controlled hydrophobic properties. J Chromatogr A 1992. [DOI: 10.1016/0021-9673(92)85459-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Agonist binding site of Torpedo electric tissue nicotinic acetylcholine receptor. A negatively charged region of the delta subunit within 0.9 nm of the alpha subunit binding site disulfide. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54614-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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11
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Zara JJ, Wood RD, Boon P, Kim CH, Pomato N, Bredehorst R, Vogel CW. A carbohydrate-directed heterobifunctional cross-linking reagent for the synthesis of immunoconjugates. Anal Biochem 1991; 194:156-62. [PMID: 1867379 DOI: 10.1016/0003-2697(91)90163-n] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A novel, highly water-soluble, heterobifunctional cross-linking reagent, S-(2-thiopyridyl)-L-cysteine hydrazide (TPCH), was synthesized which contains a hydrazide moiety for coupling to aldehyde groups generated in the carbohydrate residues of antibodies by mild periodate oxidation, and a pyridyl disulfide moiety for coupling to molecules with a free sulfhydryl group. Since the carbohydrate moieties are distal to the antigen binding region of antibodies, derivatization with this cross-linker minimizes impairment of the antigen binding function. Derivatization of the human monoclonal IgM antibody 16-88 against human colon carcinoma cells with as many as 16 TPCH cross-linker molecules did not impair its antigen binding capability. Using mild oxidation conditions for antibody derivatization, sialic acid residues were identified as attachment sites for the cross-linker molecules, since after desialylation of antibody 16-88 by neuraminidase virtually no cross-linker molecules could be incorporated. Comparison of TPCH with S-(2-thiopyridyl)mercaptopropionic acid hydrazide and S-(2-thiopyridyl)-L-cysteine, two related cross-linking reagents, revealed that TPCH is most efficiently incorporated into periodate-treated antibody. Based on the structural differences of the cross-linkers, the more efficient incorporation of TPCH appears to be a function of the presence of a hydrazide moiety with an adjacent amino group. When three to four molecules of pyridyl disulfide-derivatized barley toxin were coupled to TPCH-derivatized antibody 16-88, the antigen binding capability remained uncompromised. In addition, no significant impairment of toxin activity upon coupling to the antibody was observed. Based on these data, TPCH may be very useful for the synthesis of immuno-conjugates with no or only minimal impairment of the antigen binding function.
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Affiliation(s)
- J J Zara
- Department of Biochemistry and Molecular Biology, Georgetown University, Washington, D.C. 20007
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Michalak M, Wandler EL, Strynadka K, Lopaschuk GL, Njue WM, Liu HJ, Olley PM. Photolabelling of the prostaglandin E2 receptor in cardiac sarcolemmal vesicles. FEBS Lett 1990; 265:117-20. [PMID: 2163881 DOI: 10.1016/0014-5793(90)80898-s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A [3H]azidophenacyl ester of PGE2 ([3H]azido-PGE2) was synthesized and used to photoaffinity label the protein component of the high affinity PGE2 binding site in cardiac sarcolemma membrane. Photolysis of the isolated cardiac sarcolemmal vesicles in the presence of [3H]azido-PGE2 resulted in the covalent labelling of a protein component that migrated on sodium dodecyl sulfate-polyacrylamide gels with an apparent molecular weight of 100,000. Incorporation of the [3H]azido-PGE2 did not occur in the absence of photolysis. The photolabelling of the 100-kDa protein by [3H]azido-PGE2 was inhibited by excess unlabelled PGE2 and azido-PGE2. Specific binding of [3H]azido-PGE2 was displaced by excess unlabelled PGE2 or azido-PGE2, but not PGF2 alpha, 6-keto-PGF1 alpha or PGD2. These results indicate that the 100-kDa photoaffinity labelled [3H]azido-PGE2 binding protein contains the binding site for PGE2 in isolated cardiac sarcolemma membranes.
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Affiliation(s)
- M Michalak
- Cardiovascular Disease Research Group, University of Alberta, Edmonton, Canada
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Dhanasekaran N, Wessling-Resnick M, Kelleher DJ, Johnson GL, Ruoho AE. Mapping of the carboxyl terminus within the tertiary structure of transducin's alpha subunit using the heterobifunctional cross-linking reagent, 125I-N-(3-iodo-4-azidophenylpropionamido-S-(2-thiopyridyl) cysteine. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81307-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Feeney RE. Chemical modification of proteins: comments and perspectives. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1987; 29:145-61. [PMID: 3570660 DOI: 10.1111/j.1399-3011.1987.tb02241.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The use of chemical modification of proteins has increased exponentially during the past two decades. Today the many different uses of chemical modification include determination of relative reactivities of side chain groups, the quantitation of individual amino acids, development of affinity reagents, mechanism-based reagents for pharmaceutical uses, cross-linking reagents, special techniques for bioprostheses, blocking reagents for peptide synthesis, and reagents for specific cleavages of peptide bonds. Chemical modification should continue to be a primary tool in protein chemistry. It can supply information or products difficult or impossible to attain by the newer powerful technique of in vitro mutagenesis as well as serve as a supplementary procedure for the latter.
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Cachia PJ, Van Eyk J, McCubbin WD, Kay CM, Hodges RS. Ion-exchange high-performance liquid chromatographic purification of bovine cardiac and rabbit skeletal muscle troponin subunits. JOURNAL OF CHROMATOGRAPHY 1985; 343:315-28. [PMID: 4066873 DOI: 10.1016/s0378-4347(00)84600-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Bovine cardiac and rabbit skeletal troponin complexes were separated into their respective subunits employing high-performance liquid chromatographic (HPLC) techniques on CM-300 and Q-300 ion-exchangers. Bovine cardiac and rabbit skeletal subunits were separated on the strong anion-exchanger, Q-300, in 8 M urea, 50 mM Tris, 2 mM EGTA, 0.5 mM dithiothreitol, pH 7.5, employing a linear salt gradient and on the weak cation-exchanger, CM-300, in 8 M urea, 50 mM potassium dihydrogen phosphate, 2 mM EGTA, 0.5 mM dithiothreitol, pH 6.5, using a linear salt gradient. To obtain complete purification of all components of troponin both ion-exchangers were required. The initial separation of troponin was carried out on the strong anion-exchanger followed by weak cation-exchange chromatography of the troponin I collected from the strong anion-exchange column. The troponin T subunits obtained from Q-300 chromatography demonstrated heterogeneity (three components: T1, T2 and T3) while the troponin I collected from both sources on the Q-300 column were both resolved into major doublets (I1 and I2) when rechromatographed on the CM-300 column. The three troponin T fractions and two troponin I fractions isolated from ion-exchange HPLC were examined by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis to confirm that the heterogeneity was due to differences in charge and not molecular weight. These results were in agreement with the charge differences observed from retention times on ion-exchange HPLC. When comparing the same troponin subunit from different muscle sources, considerable differences in the content of charged amino acid residues were also observed.
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Abstract
A water-soluble, cleavable, heterobifunctional photoaffinity label has been synthesized in one step from N-hydroxysuccinimidyl 4-azidobenzoate and cystine. The resultant compound, N,N'-bis(4-azidobenzoyl) cystine [(ABC)2], reacts with protein sulfhydryl groups through disulfide exchange to generate photoactive derivatives. Since [35S]cystine of high specific activity is readily available, it is possible to produce highly radioactive (ABC)2. ABC-derivatized ovalbumin is antigenic in vivo, and monoclonal antibodies specific for ABC have been produced. The antigen binding site of these antibodies was covalently labeled with ABC.
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Abstract
A new chemical crosslinking reagent, 1-[N-(2-hydroxy-5-azidobenzoyl) -2-aminoethyl]-4-(N-hydroxysuccinimidyl)-succinate, or HAHS, has been developed. It is synthesized in three steps and stored as an unlabeled precursor, and then iodinated immediately before use. The reagent has a succinimide ester at one end so that it can be covalently attached to a purified protein, and a radioiodinated phenyl azide group at the other end, so that upon photolysis it can form crosslinks to nearby molecules. The 16-A connecting region contains an ester group which is very stable at neutral pH before photolysis, but which hydrolyzes in about 1 min in base, and hydrolyzes spontaneously after photolysis. Thus, photolysis and cleavage of the ester result in transfer of the radiolabel from the initial protein to its neighbors. When 125I-HAHS-protein A was incubated with IgG, photolyzed, and cleaved, 27% of the label was transferred to the IgG heavy chain. This transfer was abolished by an excess of unlabeled protein A, and was quenched by low concentrations of DTT. Much lower amounts of label were transferred to noninteracting proteins. When 125I-HAHS-spectrin was bound to spectrin-depleted red blood cell membranes, photolyzed, and cleaved, label was transferred only to ankyrin and to band 3. This transfer was blocked by excess unlabeled spectrin and was greatly diminished by conditions which prevent binding of spectrin.
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Shih LB, Bayley H. A carbene-yielding amino acid for incorporation into peptide photoaffinity reagents. Anal Biochem 1985; 144:132-41. [PMID: 3985309 DOI: 10.1016/0003-2697(85)90094-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
3-[p-[3-(Trifluoromethyl)-3H-diazirin-3-yl]phenyl]alanine has been prepared in 10 steps from p-bromobenzyl alcohol. The alcohol was converted to 3-(alpha-iodo-p-tolyl)-3-(trifluoromethyl)-3H-diazirine, which was used to alkylate N-(diphenylmethylene)glycine ethyl ester. After deprotection the amino acid was obtained with an overall yield of 18%. The D- and L-isomers of 3-[p-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenyl]alanine have also been resolved, and 3-[p-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenyl]alanine labeled with tritium has been prepared. The advantages of using this amino acid as a building block for peptide photoaffinity reagents is discussed.
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Parker JMR, Hodges RS. I. Photoaffinity probes provide a general method to prepare synthetic peptide-conjugates. ACTA ACUST UNITED AC 1984. [DOI: 10.1007/bf01025065] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Parker JMR, Hodges RS. II. Photoaffinity probes provide a general method to prepare peptide-conjugates from native protein fragments. ACTA ACUST UNITED AC 1984. [DOI: 10.1007/bf01025066] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Trifluoperazine (TFP) was shown to interact with the cyanogen bromide fragment 9 (CB9) (residues 84-135) of rabbit skeletal troponin C and with a synthetic peptide representing the N-terminal region of CB9. The phenothiazine did not affect the calcium binding property of CB9 as observed by proton magnetic resonance and circular dichroism spectroscopies. The calculated calcium binding constants for CB9 in the presence and absence of trifluoperazine were identical (KCa2+ = 1.3 X 10(5) M-1). Localization of the trifluoperazine binding site was achieved by analyzing the 1H NMR spectrum of CB9 and of a synthetic fragment corresponding to residues 90-104 of CB9. Drug-induced shifting and broadening of the ring protons of phenylalanine residues and the methyl resonances of alanine, leucine, and isoleucine residues suggest that the segment 95-102 is in close proximity to the phenothiazine aromatic region. The neighboring negative side chains in the peptide sequence also suggest that the single positive charge present on the piperazine nitrogens of trifluoperazine may interact with them and sterically block a region of interaction of calmodulin (CaM) and troponin C (TnC) with modulated proteins such as phosphodiesterase. Primary sequence analysis of CaM and troponin C reveals that a homologous hydrophobic region to site 3 is also found in the N-terminal region of site 1 of both calcium binding proteins. Binding of TFP to CB9 occurs both in the presence and absence of calcium since the hydrophobic region in these small fragments is completely accessible to TFP whether calcium is present or not. The dissociation constant of the drug to apoCB9 (8 microM) was obtained by ellipticity measurements at 222 nm and was comparable to the 5 microM value obtained by Levin and Weiss [Levin, R. M., & Weiss, B. (1978) Biochim. Biophys. Acta 540, 197-204] for calcium-saturated rabbit skeletal troponin C.
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Worobec EA, Taneja AK, Hodges RS, Paranchych W. Localization of the major antigenic determinant of EDP208 pili at the N-terminus of the pilus protein. J Bacteriol 1983; 153:955-61. [PMID: 6185467 PMCID: PMC221719 DOI: 10.1128/jb.153.2.955-961.1983] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Trypsin digestion of pilin monomers from EDP208 conjugative pili causes cleavage of Lys12 to yield an N-terminal dodecapeptide, ET1 (Mr approximately equal to 1,500), and the remaining C-terminal fragment, ER (Mr approximately equal to 10,000). Using the amino acid sequence for ET1 provided by Frost et al. (J. Bacteriol. 153:950-954), we synthesized the N-terminal dodecapeptide chemically, conjugated it to bovine serum albumin, and subjected it to immunological studies. Antisera prepared against intact EDP208 pili as well as against the synthetic ET1-BSA conjugate were used in experiments involving an enzyme-linked immunosorbant assay and electrophoretic transfer of proteins from sodium dodecyl sulfate-polyacrylamide gels to nitrocellulose sheets. Both experimental approaches showed strong reactivity between the synthetic dodecapeptide and antiserum raised against whole pili. It was also found that antiserum raised against the synthetic peptide was reactive against intact pilus protein, indicating that the N-terminal dodecapeptide is an important antigenic determinant of the EDP208 pilus protein. Additional studies showed that the C-terminal fragment, ER, may contain one or two additional antigenic sites.
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Photochemical cross-linking between rabbit skeletal troponin subunits. Troponin I-troponin T interactions. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33814-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Chong PC, Hodges RS. Photochemical cross-linking between rabbit skeletal troponin and alpha-tropomyosin. Attachment of the photoaffinity probe N-(4-azidobenzoyl-[2-3H]glycyl)-S-(2-thiopyridyl)-cysteine to cysteine 190 of alpha-tropomyosin. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34255-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Proximity of sulfhydryl groups to the sites of interaction between components of the troponin complex from rabbit skeletal muscle. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34959-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Chong P, Hodges R. A new heterobifunctional cross-linking reagent for the study of biological interactions between proteins. II. Application to the troponin C-troponin I interaction. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69368-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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