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Khan S, Ansari B, Ansari NK, Naeem A. Protective role of chlorogenic acid in preserving cytochrome-c stability against HFIP-induced molten globule state at physiological pH. Int J Biol Macromol 2024; 261:129845. [PMID: 38302016 DOI: 10.1016/j.ijbiomac.2024.129845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/03/2024]
Abstract
Numerous neurodegenerative disorders are characterized by protein misfolding and aggregation. The mechanism of protein aggregation is intricate, and it is very challenging to study at cellular level. Inhibition of protein aggregation by interfering with its pathway is one of the ways to prevent neurodegenerative diseases. In the present work, we have evaluated the protective effect of a polyphenol compound chlorogenic acid (CGA) on the native and molten globule state of horse heart cytochrome c (cyt c). A molten globule state of this heme protein was achieved in the presence of fluorinated alcohol 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) at physiological pH, as studied by UV-Vis absorption, circular dichroism, intrinsic and ANS fluorescence. We found that at 50 % (v/v) HFIP, the native cyt c transformed into a molten globule state. The same techniques were also used to analyze the protective effect of CGA on the molten globule state of cyt c, and the results show that the CGA prevented the molten globular state and retained the protein close to the native state at 1:1 protein:CGA sub molar ratio. Molecular dynamics study also revealed that CGA retains the stability of cyt c in HFIP medium by preserving it in an intermediate state close to native conformation.
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Affiliation(s)
- Sadaf Khan
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India.
| | - Bushra Ansari
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India
| | - Neha Kausar Ansari
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India.
| | - Aabgeena Naeem
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India.
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Sun Y, Oseliero Filho PL, Song Y, Wang Z, Ji H, Oliveira CLP. The role of hydrophobic interactions in the molten globule state of globular protein modulated by surfactants. Colloids Surf B Biointerfaces 2023; 230:113490. [PMID: 37556880 DOI: 10.1016/j.colsurfb.2023.113490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/25/2023] [Accepted: 07/31/2023] [Indexed: 08/11/2023]
Abstract
In order to highlight the role of hydrophobic interactions in the molten globule (MG) state of globular protein modulated by surfactants, the interactions of bovine α-lactalbumin (α-LA) with alkyl trimethylammonium bromides (CnTAB, n = 10, 12, 14, and 16) have been studied by experimental and theoretical techniques. Isothermal titration calorimetry (ITC) showed that the enthalpy changes (ΔH) and area of the enthalpogram increased with increasing the chain length of CnTAB. The result of fluorescence, circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) spectrum suggested that C10TAB and C12TAB unfolded α-LA partially, C14TAB reconstructed protein with a native-like secondary structure content, and C16TAB induced an MG state α-LA. The SAXS results confirmed that the tertiary structure of α-LA was disrupted by C16TAB forming an MG state complex with a micelle-like structure even at the surfactants concentrations below CMC. As indicated by MD results, the β-domain and unstructured region(s) were involved in the MG state α-LA modulated by CnTAB. This work not only provides molecular insights into the role of hydrophobic interactions in the MG state of a globular protein but also helps understand the mechanism of preparing α-LA based biomacromolecule modulated by hydrophobic interactions.
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Affiliation(s)
- Yang Sun
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China.
| | | | - Yang Song
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Zhichun Wang
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Hang Ji
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
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Abstract
Interest in protein folding intermediates lies in their significance to protein folding pathways. The molten globule (MG) state is one such intermediate lying on the kinetic (and sometimes thermodynamic) pathway between native and unfolded states. Development of our qualitative and quantitative understanding of the MG state can provide deeper insight into the folding pathways and hence potentially facilitate solution of the protein folding problem. An extensive look at literature suggests that most studies into protein MG states have been largely qualitative. Attempts to obtain quantitative insights into MG states have involved application of high-sensitivity calorimetry (differential scanning calorimetry and isothermal titration calorimetry). This review addresses the progress made in this direction by discussing the knowledge gained to date, along with the future promise of calorimetry, in providing quantitative information on the structural features of MG states. Particular attention is paid to the question of whether such states share common structural features or not. The difference in the nature of the transition from the MG state to the unfolded state, in terms of cooperativity, has also been addressed and discussed.
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Affiliation(s)
- Eva Judy
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076 India
| | - Nand Kishore
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076 India
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Park HW, Kim DY, Shin WS. Fucoidan improves the structural integrity and the molecular stability of β-lactoglobulin. Food Sci Biotechnol 2018; 27:1247-1255. [PMID: 30319832 DOI: 10.1007/s10068-018-0375-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 03/23/2018] [Accepted: 04/03/2018] [Indexed: 10/17/2022] Open
Abstract
β-lactoglobulin (β-lg) was covalently bonded with fucoidan through Maillard reaction at 60 °C for 96 h under 79% RH condition. The molecular characters of the conjugate were investigated using fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and circular dichroism (CD) spectroscopy. And, its thermal properties, surface activity, and zeta-potential were compared with intact β-lg, β-lg-fucoidan mixture, and fucoidan under different pH conditions. AFM indicated that the conjugate was nano-structured, regular spherical-shaped and generally large sized compared to β-lg-fucoidan mixture. CD spectra and FT-IR showed that tertiary structure of β-lg slightly unfolded, but little change in secondary structure occurred. This explained that glycation under Maillard condition resulted in a molten globule state of β-lg. Differential scanning calorimetry (DSC) data exhibited that fucoidan shifted the temperature of phase transition and improved thermal stability of β-lg molecule. In addition, the conjugate prominently decreased the surface tension with pH-dependency.
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Affiliation(s)
- Hyun-Woong Park
- Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul, 04763 Republic of Korea
| | - Do-Yeong Kim
- Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul, 04763 Republic of Korea
| | - Weon-Sun Shin
- Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul, 04763 Republic of Korea
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Dar MA, Wahiduzzaman, Haque MA, Islam A, Hassan MI, Ahmad F. Characterisation of molten globule-like state of sheep serum albumin at physiological pH. Int J Biol Macromol 2016; 89:605-13. [PMID: 27180298 DOI: 10.1016/j.ijbiomac.2016.05.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 05/10/2016] [Indexed: 01/26/2023]
Abstract
Sheep serum albumin (SSA) is a 583 amino acid residues long multidomain monomeric protein which is rich in cysteine and low in tryptophan content. The serum albumins (from human, bovine and sheep) play a vital role among all proteins investigated until now, as they are the most copious circulatory proteins. We have purified SSA from sheep kidneys by a simple and efficient two-step purification procedure. Further, we have studied urea-induced denaturation of SSA by monitoring changes in the difference absorption coefficient at 287nm (Δε287), intrinsic fluorescence emission intensity at 347nm (F347) and mean residue ellipticity at 222nm ([θ]222) at pH 7.4 and 25°C. The coincidence of denaturation curves of these optical properties suggests that urea-induced denaturation is a bi-phasic process (native (N) state↔intermediate (X) state↔denatured (D) state) with a stable intermediate populated around 4.2-4.7M urea. The intermediate (X) state was further characterized by the far-UV and near-UV CD, dynamic light scattering (DLS) and fluorescence using 1-anilinonaphthalene-8-sulfonic acid (ANS) binding method. All denaturation curves were analyzed for Gibbs free energy changes associated with the equilibria, N state↔X state and X state↔D state in the absence of urea.
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Valipour M, Maghami P, Habibi-Rezaei M, Sadeghpour M, Khademian MA, Mosavi K, Sheibani N, Moosavi-Movahedi AA. Interaction of insulin with methyl tert-butyl ether promotes molten globule-like state and production of reactive oxygen species. Int J Biol Macromol 2015; 80:610-4. [PMID: 26193678 DOI: 10.1016/j.ijbiomac.2015.07.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 11/25/2022]
Abstract
Interaction of methyl tert-butyl ether (MTBE) with proteins is a new look at its potential adverse biological effects. When MTBE is released to the environment it enters the blood stream through inhalation, and could affect the properties of various proteins. Here we investigated the interaction of MTBE with insulin and its effect on insulin structural changes. Our results showed that insulin formed a molten globule (MG)-like structure in the presence of 8 μM MTBE under physiological pH. The insulin structural changes were studied using spectroscopy methods, viscosity calculation, dynamic light scattering and differential scanning calorimetry. To delineate the mechanisms involved in MTBE-protein interactions, the formation of reactive oxygen specious (ROS) and formation of protein aggregates were measured. The chemiluminscence experiments revealed an increase in ROS production in the presence of MTBE especially in the MG-like state. These results were further confirmed by the aggregation tests, which indicated more aggregation of insulin at 40 μM MTBE compared with 8 μM. Thus, the formation of initial aggregates and exposure of the hydrophobic patches upon formation of the MG-like state in the presence of MTBE drives protein oxidation and ROS generation.
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Affiliation(s)
- Masoumeh Valipour
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; Center of Excellence in Biothermodynamics, University of Tehran, Tehran, Iran
| | - Parvaneh Maghami
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | | | - Mostafa Sadeghpour
- Office of Health, Safety and Environment (HSE) Oil Ministry, Tehran, Iran
| | | | - Khadijeh Mosavi
- Office of Health, Safety and Environment (HSE) Oil Ministry, Bandar Mahshahr, Iran
| | - Nader Sheibani
- Departments of Ophthalmology and Visual Sciences and Biomedical Engineering, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Ali Akbar Moosavi-Movahedi
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; Center of Excellence in Biothermodynamics, University of Tehran, Tehran, Iran.
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Kim DY, Shin WS. Characterisation of bovine serum albumin-fucoidan conjugates prepared via the Maillard reaction. Food Chem 2014; 173:1-6. [PMID: 25465988 DOI: 10.1016/j.foodchem.2014.09.167] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/06/2014] [Accepted: 09/29/2014] [Indexed: 11/28/2022]
Abstract
Bovine serum albumin (BSA)-fucoidan conjugates were prepared by the Maillard reaction (60 °C and 79% relative humidity for 96 h), and were then identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and size-exclusion chromatography (SEC). Molecular characteristics of the BSA-fucoidan conjugates were investigated, using atomic force microscopy (AFM), dynamic light scattering (DLS), fluorescence spectroscopy, and circular dichroism spectroscopy. SDS-PAGE patterns provided evidence for the covalent bonding between BSA and fucoidan. SEC profiles showed that about 1.5-2.0 mol of fucoidan were covalently linked to 1 mol of BSA, resulting in high-molecular-weight compositions (conjugates). AFM images and DLS results indicated that most particles in the conjugates were nano-structured and more spherical than those of a regular BSA-fucoidan mixture. The fluorescence intensity and maximum emission wavelength of the conjugates together revealed that the BSA molecules had converted from an ordered conformation into a partially folded molten globule state.
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Affiliation(s)
- Do-Yeong Kim
- Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul 133-791, Republic of Korea
| | - Weon-Sun Shin
- Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul 133-791, Republic of Korea.
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