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Wu GL, Shi YJ, Chiou JT, Huang CH, Lee YC, Wang LJ, Chang LS. Functional and structural properties of cardiotoxin isomers produced by blocking negatively charged groups. Arch Biochem Biophys 2022; 722:109209. [DOI: 10.1016/j.abb.2022.109209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/30/2022]
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Monitoring the Disulfide Bonds of Folding Isomers of Synthetic CTX A3 Polypeptide Using MS-Based Technology. Toxins (Basel) 2019; 11:toxins11010052. [PMID: 30658470 PMCID: PMC6356385 DOI: 10.3390/toxins11010052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 12/19/2022] Open
Abstract
Native disulfide formation is crucial to the process of disulfide-rich protein folding in vitro. As such, analysis of the disulfide bonds can be used to track the process of the folding reaction; however, the diverse structural isomers interfere with characterization due to the non-native disulfide linkages. Previously, a mass spectrometry (MS) based platform coupled with peptide demethylation and an automatic disulfide bond searching engine demonstrated the potential to screen disulfide-linked peptides for the unambiguous assignment of paired cysteine residues of toxin components in cobra venom. The developed MS-based platform was evaluated to analyze the disulfide bonds of structural isomers during the folding reaction of synthetic cardiotoxin A3 polypeptide (syn-CTX A3), an important medical component in cobra venom. Through application of this work flow, a total of 13 disulfide-linked peptides were repeatedly identified across the folding reaction, and two of them were found to contain cysteine pairings, like those found in native CTX A3. Quantitative analysis of these disulfide-linked peptides showed the occurrence of a progressive disulfide rearrangement that generates a native disulfide bond pattern on syn-CTX A3 folded protein. The formation of these syn-CTX A3 folded protein reaches a steady level in the late stage of the folding reaction. Biophysical and cell-based assays showed that the collected syn-CTX A3 folded protein have a β-sheet secondary structure and cytotoxic activity similar to that of native CTX A3. In addition, the immunization of the syn-CTX A3 folded proteins could induce neutralization antibodies against the cytotoxic activity of native CTX A3. In contrast, these structure activities were poorly observed in the other folded isomers with non-native disulfide bonds. The study highlights the ability of the developed MS platform to assay isomers with heterogeneous disulfide bonds, providing insight into the folding mechanism of the bioactive protein generation.
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Putative membrane lytic sites of P-type and S-type cardiotoxins from snake venoms as probed by all-atom molecular dynamics simulations. J Mol Model 2016; 22:238. [DOI: 10.1007/s00894-016-3113-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/01/2016] [Indexed: 12/16/2022]
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Gorai B, Prabhavadhni A, Sivaraman T. Unfolding stabilities of two structurally similar proteins as probed by temperature-induced and force-induced molecular dynamics simulations. J Biomol Struct Dyn 2014; 33:2037-47. [DOI: 10.1080/07391102.2014.986668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Huang SY, Chen SF, Chen CH, Huang HW, Wu WG, Sung WC. Global Disulfide Bond Profiling for Crude Snake Venom Using Dimethyl Labeling Coupled with Mass Spectrometry and RADAR Algorithm. Anal Chem 2014; 86:8742-50. [DOI: 10.1021/ac501931t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Sheng Yu Huang
- Mithra Biotechnology
Inc., 7F, No. 104, Sec. 1, Xintai 5th
Road, Xizhi Dist., New Taipei City 221, Taiwan
| | - Sung Fang Chen
- National Taiwan Normal University, Department of
Chemistry, No. 88, Sec.
4, Tingchow Road, Taipei 116, Taiwan
| | - Chun Hao Chen
- National Taiwan Normal University, Department of
Chemistry, No. 88, Sec.
4, Tingchow Road, Taipei 116, Taiwan
| | - Hsuan Wei Huang
- National Health
Research Institutes, National Institute of Infectious Diseases and
Vaccinology, No. 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan
- National Tsing Hua University, Institute of Bioinformatics
and Structural Biology, No. 101, Sec. 2, Kuang Fu Road, Hsinchu 330, Taiwan
| | - Wen Guey Wu
- National Tsing Hua University, Institute of Bioinformatics
and Structural Biology, No. 101, Sec. 2, Kuang Fu Road, Hsinchu 330, Taiwan
| | - Wang Chou Sung
- National Health
Research Institutes, National Institute of Infectious Diseases and
Vaccinology, No. 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan
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Kumar TKS, Sivaraman T, Samuel D, Srisailam S, Ganesh G, Hsieh HC, Hung KW, Peng HJ, Ho MC, Arunkumar AI, Yu C. Protein Folding and β-Sheet Proteins. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200000141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ponnappa KC, Saviour P, Ramachandra NB, Kini RM, Gowda TV. INN-toxin, a highly lethal peptide from the venom of Indian cobra (Naja naja) venom-Isolation, characterization and pharmacological actions. Peptides 2008; 29:1893-900. [PMID: 18760317 DOI: 10.1016/j.peptides.2008.07.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 07/30/2008] [Accepted: 07/30/2008] [Indexed: 11/20/2022]
Abstract
A novel toxic polypeptide, INN-toxin, is purified from the venom of Naja naja using combination of gel-permeation and ion-exchange chromatography. It has a molecular mass of 6951.6Da as determined by MALDI-TOF/MS and the N-terminal sequence of LKXNKLVPLF. It showed both neurotoxic as well as cytotoxic activities. INN-toxin is lethal to mice with a LD(50) of 1.2mg/kg body weight. IgY raised in chicks against basic peptide pool neutralized the toxicity of INN-toxin. INN-toxin did not inhibit cholinesterase activity. It is toxic to Ehrlich ascites tumor (EAT) cells, but it is not toxic to leukocyte culture. The toxin appears to be specific in its mode of action. Interaction of N-bromosuccinamide (NBS) with the peptide resulted in the modification of tryptophan residues and loss of lethal toxicity of INN-toxin.
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Affiliation(s)
- K C Ponnappa
- Department of Studies in Biochemistry, Manasagangotri, University of Mysore, Mysore 570 006, India
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Chang JY, Lu BY, Lin CCJ, Yu C. Fully oxidized scrambled isomers are essential and predominant folding intermediates of cardiotoxin-III. FEBS Lett 2005; 580:656-60. [PMID: 16412427 DOI: 10.1016/j.febslet.2005.12.064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 12/01/2005] [Accepted: 12/02/2005] [Indexed: 11/30/2022]
Abstract
Scrambled isomers (X-isomers) are fully oxidized, non-native isomers of disulfide proteins. They have been shown to represent important intermediates along the pathway of oxidative folding of numerous disulfide proteins. A simple method to assess whether X-isomers present as folding intermediate is to conduct oxidative folding of fully reduced protein in the alkaline buffer alone without any supplementing thiol catalyst or redox agent. Cardiotoxin-III (CTX-III) contains 60 amino acids and four disulfide bonds. The mechanism of oxidative folding of CTX-III has been systematically characterized here by analysis of the acid trapped folding intermediates. Folding of CTX-III was shown to proceed sequentially through 1-disulfide, 2-disulfide, 3-disulfide and 4-disulfide (scrambled) isomers as folding intermediates to reach the native structure. When folding of CTX-III was performed in the buffer alone, more than 97% of the protein was trapped as 4-disulfide X-isomers, unable to convert to the native structure due to the absence of thiol catalyst. In the presence of thiol catalyst (GSH) or redox agents (GSH/GSSG), the recovery of native CTX-III was 80-85%. These results demonstrate that X-isomers play an essential and predominant role in the oxidative folding of CTX-III.
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Affiliation(s)
- Jui-Yoa Chang
- Research Center for Protein Chemistry, Institute of Molecular Medicine, The University of Texas, Houston, TX 77030, USA.
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Min CY, Qiao ZS, Feng YM. Unfolding of human proinsulin. Intermediates and possible role of its C-peptide in folding/unfolding. ACTA ACUST UNITED AC 2004; 271:1737-47. [PMID: 15096212 DOI: 10.1111/j.1432-1033.2004.04079.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the in vitro refolding process of human proinsulin (HPI) and an artificial mini-C derivative of HPI (porcine insulin precursor, PIP), and found that they have significantly different disulfide-formation pathways. HPI and PIP differ in their amino acid sequences due to the presence of the C-peptide linker found in HPI, therefore suggesting that the C-peptide linker may be responsible for the observed difference in folding behaviour. However, the manner in which the C-peptide contributes to this difference is still unknown. We have used both the disulfide scrambling method and a redox-equilibrium assay to assess the stability of the disulfide bridges. The results show that disulfide reshuffling is easier to induce in HPI than in PIP by the addition of thiol reagent. Thus, the C-peptide may affect the unique folding pathway of HPI by allowing the disulfide bonds of HPI to be easily accessible. The detailed processes of HPI unfolding by reduction of its disulfide bonds and by disulfide scrambling methods were also investigated. In the reductive unfolding process no accumulation of intermediates was detected. In the process of unfolding by disulfide scrambling, HPI gradually rearranged its disulfide bonds to form three major isomers G1, G2 and G3. The most abundant isomer, G1, contains the B7-B19 disulfide bridge. Based on far-UV CD spectra, native gel analysis and cleavage by endoproteinase V8, the G1 isomer has been shown to resemble the intermediate P4 found in the refolding process of HPI. Finally, the major isomer G1 is allowed to refold to native protein HPI by disulfide rearrangement, which indicates that a similar molecular mechanism may exist for the unfolding and refolding process of HPI.
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Affiliation(s)
- Cheng-Yin Min
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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Salamanca S, Villegas V, Vendrell J, Li L, Aviles FX, Chang JY. The unfolding pathway of leech carboxypeptidase inhibitor. J Biol Chem 2002; 277:17538-43. [PMID: 11893741 DOI: 10.1074/jbc.m200040200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The unfolding and denaturation curves of leech carboxypeptidase inhibitor (LCI) were elucidated using the technique of disulfide scrambling. In the presence of thiol initiator and denaturant, the native LCI denatures by shuffling its native disulfide bonds and transforms into a mixture of scrambled species. 9 of 104 possible scrambled isomers of LCI, amounting to 90% of total denatured LCI, can be distinguished. The denaturation curve that plots the fraction of native LCI converted into scrambled isomers upon increasing concentrations of denaturant shows that the concentration of guanidine thiocyanate and guanidine hydrochloride required to reach 50% of denaturation is 2.4 and 3.6 m, respectively. In contrast, native LCI is resistant to urea denaturation even at high concentration (8 m). The LCI unfolding pathway was defined based on the evolution of the relative concentration of scrambled isoforms of LCI upon denaturation. Two populations of scrambled species suffer variations along the unfolding pathway. One accumulates as intermediates under strong denaturing conditions and corresponds to open or relaxed structures, among which the beads-form isomer is found. The other population shows an inverse correlation between their relative abundances and the denaturing conditions and should have another kind of non-native structure that is more compact than the unfolded state. The rate constants of unfolding of LCI are low when compared with other disulfide-containing proteins. Overall, the results presented in this study show that LCI, a molecule with potential biotechnological applications, has slow kinetics of unfolding and is highly stable.
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Affiliation(s)
- Silvia Salamanca
- Institut de Biotecnologia i Biomedicina i Departament de Bioquimica i Biologia Molecular, Universitat Autònoma de Barcelona 08193 Bellaterra, Spain
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Chang LS, Lin SR, Yang CC. Refolding of Taiwan cobra neurotoxin: intramolecular cross-link affects its refolding reaction. Arch Biochem Biophys 2001; 387:289-96. [PMID: 11370853 DOI: 10.1006/abbi.2000.2236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to explore the effect of intramolecular cross-linking in the folding reaction of cobrotoxin from Naja naja atra (Taiwan cobra) venom, the toxin molecule was modified with glutaraldehyde (GA). The monomeric GA-modified cobrotoxin (mGA-cobrotoxin) was separated from the dimeric and trimeric derivatives using gel filtration. The results of electrophoretic and chromatographic analyses revealed that mGA-cobrotoxin comprised two modified derivatives, which contained modified Lys residues at positions 26 and 27 and at positions 26, 27, and 47, respectively. Moreover, an intramolecular cross-linking of loops II and III by Lys residues was noted with the monomeric derivative containing three modified Lys residues. In sharp contrast to cobrotoxin observations, the folding rate of mGA-cobrotoxin decreased in the presence of GSH/ GSSG, but notably increased in the absence of thiol compounds. Particularly, the accelerated effect of GSH/GSSG on the refolding reaction was affected by the presence of the intramolecular cross-link. Comparative analyses on cobrotoxin and mGA-cobrotoxin CD spectra revealed that modification with the GA reagent caused a change in the gross conformation of cobrotoxin. Fluorescence measurement revealed that the stability of the microenvironment around the single Trp-29 in mGA-cobrotoxin and unfolded mGA-cobrotoxin was appreciably higher than in cobrotoxin and unfolded toxin. Moreover, the ordered structure formation around Trp-29 in refolded mGA-cobrotoxin was faster than in refolded cobrotoxin as evidenced by fluorescence quenching studies. Taken together, these results suggest that the structural flexibility of unfolded cobrotoxin should be favorable for the thiol catalyst to exert its action in the refolding reaction after modification with GA.
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Affiliation(s)
- L S Chang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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Chang JY, Li L, Canals F, Aviles FX. The unfolding pathway and conformational stability of potato carboxypeptidase inhibitor. J Biol Chem 2000; 275:14205-11. [PMID: 10799497 DOI: 10.1074/jbc.275.19.14205] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The unfolding and denaturation curves of potato carboxypeptidase inhibitor (PCI) were investigated using the technique of disulfide scrambling. In the presence of denaturant and thiol initiator, the native PCI denatures by shuffling its native disulfide bonds and converts to form a mixture of scrambled PCI that consists of 9 out of a possible 14 isomers. The denaturation curve is determined by the fraction of native PCI converted to scrambled isomers under increasing concentrations of denaturant. The concentration of guanidine thiocyanate, guanidine hydrochloride, and urea required to denature 50% of the native PCI was found to be 0.7, 1.45, and 8 m, respectively. The PCI unfolding curve was constructed through the analysis of structures of scrambled isomers that were denatured under increasing concentrations of denaturant. These results reveal the existence of structurally defined unfolding intermediates and a progressive expansion of the polypeptide chain. The yield of the beads-form isomer (Cys(8)-Cys(12), Cys(18)-Cys(24), and Cys(27)-Cys(34)) as a fraction of total denatured PCI was shown to be directly proportional to the strength of the denaturing condition. Furthermore, the PCI sequence was unable to fold quantitatively into a single native structure. Under physiological conditions, the scrambled isomers of PCI that constitute about 4% of the protein were in equilibrium with native PCI.
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Affiliation(s)
- J Y Chang
- Research Center for Protein Chemistry, Institute of Molecular Medicine, University of Texas, Houston, Texas 77030, USA.
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Jayaraman G, Kumar TK, Tsai CC, Srisailam S, Chou SH, Ho CL, Yu C. Elucidation of the solution structure of cardiotoxin analogue V from the Taiwan cobra (Naja naja atra)--identification of structural features important for the lethal action of snake venom cardiotoxins. Protein Sci 2000; 9:637-46. [PMID: 10794406 PMCID: PMC2144616 DOI: 10.1110/ps.9.4.637] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of the present study is to understand the structural features responsible for the lethal activity of snake venom cardiotoxins. Comparison of the lethal potency of the five cardiotoxin isoforms isolated from the venom of Taiwan cobra (Naja naja atra) reveals that the lethal potency of CTX I and CTX V are about twice of that exhibited by CTX II, CTX III, and CTX IV. In the present study, the solution structure of CTX V has been determined at high resolution using multidimensional proton NMR spectroscopy and dynamical simulated annealing techniques. Comparison of the high resolution solution structures of CTX V with that of CTX IV reveals that the secondary structural elements in both the toxin isoforms consist of a triple and double-stranded antiparallel beta-sheet domains. Critical examination of the three-dimensional structure of CTX V shows that the residues at the tip of Loop III form a distinct "finger-shaped" projection comprising of nonpolar residues. The occurrence of the nonpolar "finger-shaped" projection leads to the formation of a prominent cleft between the residues located at the tip of Loops II and III. Interestingly, the occurrence of a backbone hydrogen bonding (Val27CO to Leu48NH) in CTX IV is found to distort the "finger-shaped" projection and consequently diminish the cleft formation at the tip of Loops II and III. Comparison of the solution structures and lethal potencies of other cardiotoxin isoforms isolated from the Taiwan cobra (Naja naja atra) venom shows that a strong correlation exists between the lethal potency and occurrence of the nonpolar "finger-shaped" projection at the tip of Loop III. Critical analysis of the structures of the various CTX isoforms from the Taiwan cobra suggest that the degree of exposure of the cationic charge (to the solvent) contributed by the invariant lysine residue at position 44 on the convex side of the CTX molecules could be another crucial factor governing their lethal potency.
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Affiliation(s)
- G Jayaraman
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
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Structures of scrambled disulfide forms of the potato carboxypeptidase inhibitor predicted by molecular dynamics simulations with constraints. Proteins 2000. [DOI: 10.1002/1097-0134(20000815)40:3<482::aid-prot150>3.0.co;2-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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