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Devassy AM, Kamalakshan A, Jamuna NA, Ansilda R, Mandal S. Enhanced Catalytic Activity of a New Nanobiocatalytic System Formed by the Adsorption of Cytochrome c on Pluronic Triblock Copolymer Stabilized MoS 2 Nanosheets. ACS OMEGA 2022; 7:16593-16604. [PMID: 35601299 PMCID: PMC9118411 DOI: 10.1021/acsomega.2c00839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/15/2022] [Indexed: 06/15/2023]
Abstract
The formation of nanobiohybrids through the immobilization of enzymes on functional nanomaterials has opened up exciting research opportunities at the nanobiointerfaces. These systems hold great promise for a wide range of applications in biosensing, biocatalytic, and biomedical fields. Here, we report the formation of a hybrid nanobiocatalytic system through the adsorption of cytochrome c (Cyt c) on pluronic triblock copolymer, P123 (PEO-b-PPO-b-PEO), stabilized MoS2 nanosheets. The use of pluronic polymer has helped not only to greatly stabilize the exfoliated MoS2 nanosheets but also to allow easy adsorption of Cyt c on the nanosheets without major structural changes due to its excellent biocompatibility and soft protein-binding property. By comparing the catalytic activity of the Cyt c-MoS2 nanobiohybrid with that of the free Cyt c and as-prepared MoS2 nanosheets, we have demonstrated the active role of the nanobiointeractions in enhancing the catalytic activity of the hybrid. Slight structural perturbation at the active site of the Cyt c upon adsorption on MoS2 has primarily facilitated the peroxidase activity of the Cyt c. As the MoS2 nanosheets and the native Cyt c individually exhibit weaker intrinsic peroxidase activities, their mutual modulation at the nanobiointerface has made the Cyt c-MoS2 a novel nanobiocatalyst with superior activity.
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Affiliation(s)
| | - Adithya Kamalakshan
- Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015, India
| | - Nidhi Anilkumar Jamuna
- Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015, India
| | - Roselin Ansilda
- Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015, India
| | - Sarthak Mandal
- Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015, India
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Synthesis of Chitosan-Coated Silver Nanoparticle Bioconjugates and Their Antimicrobial Activity against Multidrug-Resistant Bacteria. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11199340] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The increase in multidrug-resistant bacteria represents a true challenge in the pharmaceutical and biomedical fields. For this reason, research on the development of new potential antibacterial strategies is essential. Here, we describe the development of a green system for the synthesis of silver nanoparticles (AgNPs) bioconjugated with chitosan. We optimized a Prunus cerasus leaf extract as a source of silver and its conversion to chitosan–silver bioconjugates (CH-AgNPs). The AgNPs and CH-AgNPs were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), and zeta potential measurement (Z-potential). The cytotoxic activity of AgNPs and CH-AgNPs was assessed on Vero cells using the 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) cell proliferation assay. The antibacterial activity of AgNPs and CH-AgNPs synthesized using the green system was determined using the broth microdilution method. We evaluated the antimicrobial activity against standard ATCC and clinically isolated multisensitive (MS) and multidrug-resistant bacteria (MDR) Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Klebsiella pneumonia (K. pneumoniae), and Staphylococcus aureus (S. aureus), using minimum inhibitory concentration (MIC) assays and the broth dilution method. The results of the antibacterial studies demonstrate that the silver chitosan bioconjugates were able to inhibit the growth of MDR strains more effectively than silver nanoparticles alone, with reduced cellular toxicity. These nanoparticles were stable in solution and had wide-spectrum antibacterial activity. The synthesis of silver and silver chitosan bioconjugates from Prunus cerasus leaf extracts may therefore serve as a simple, ecofriendly, noncytotoxic, economical, reliable, and safe method to produce antimicrobial compounds with low cytotoxicity.
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Amino Acid Substitutions in the Non-Ordered Ω-Loop 70–85 Affect Electron Transfer Function and Secondary Structure of Mitochondrial Cytochrome c. CRYSTALS 2021. [DOI: 10.3390/cryst11080973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The secondary structure of horse cytochrome c with mutations in the P76GTKMIFA83 site of the Ω-loop, exhibiting reduced efficiency of electron transfer, were studied. CD spectroscopy studies showed that the ordering of mutant structure increases by 3–6% compared to that of the WT molecules due to the higher content of β-structural elements. The IR spectroscopy data are consistent with the CD results and demonstrate that some α-helical elements change into β-structures, and the amount of the non-structured elements is decreased. The analysis of the 1H-NMR spectra demonstrated that cytochrome c mutants have a well-determined secondary structure with some specific features related to changes in the heme microenvironment. The observed changes in the structure of cytochrome c mutants are likely to be responsible for the decrease in the conformational mobility of the P76GTKMIFA83 sequence carrying mutations and for the decline in succinate:cytochrome c-reductase and cytochrome c-oxidase activities in the mitoplast system in the presence of these cytochromes c. We suggest that the decreased efficiency of the electron transfer of the studied cytochromes c may arise due to: (1) the change in the protein conformation in sites responsible for the interaction of cytochrome c with complexes III and IV and (2) the change in the heme conformation that deteriorates its optimal orientation towards donor and acceptor in complexes III and IV therefore slows down electron transfer. The results obtained are consistent with the previously proposed model of mitochondrial cytochrome c functioning associated with the deterministic mobility of protein globule parts.
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Dyrka W, Gąsior-Głogowska M, Szefczyk M, Szulc N. Searching for universal model of amyloid signaling motifs using probabilistic context-free grammars. BMC Bioinformatics 2021; 22:222. [PMID: 33926372 PMCID: PMC8086366 DOI: 10.1186/s12859-021-04139-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 04/19/2021] [Indexed: 11/16/2022] Open
Abstract
Background Amyloid signaling motifs are a class of protein motifs which share basic structural and functional features despite the lack of clear sequence homology. They are hard to detect in large sequence databases either with the alignment-based profile methods (due to short length and diversity) or with generic amyloid- and prion-finding tools (due to insufficient discriminative power). We propose to address the challenge with a machine learning grammatical model capable of generalizing over diverse collections of unaligned yet related motifs. Results First, we introduce and test improvements to our probabilistic context-free grammar framework for protein sequences that allow for inferring more sophisticated models achieving high sensitivity at low false positive rates. Then, we infer universal grammars for a collection of recently identified bacterial amyloid signaling motifs and demonstrate that the method is capable of generalizing by successfully searching for related motifs in fungi. The results are compared to available alternative methods. Finally, we conduct spectroscopy and staining analyses of selected peptides to verify their structural and functional relationship. Conclusions While the profile HMMs remain the method of choice for modeling homologous sets of sequences, PCFGs seem more suitable for building meta-family descriptors and extrapolating beyond the seed sample. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04139-y.
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Affiliation(s)
- Witold Dyrka
- Wydział Podstawowych Problemów Techniki, Katedra Inżynierii Biomedycznej, Politechnika Wrocławska, Wrocław, Poland.
| | - Marlena Gąsior-Głogowska
- Wydział Podstawowych Problemów Techniki, Katedra Inżynierii Biomedycznej, Politechnika Wrocławska, Wrocław, Poland
| | - Monika Szefczyk
- Wydział Chemiczny, Katedra Chemii Bioorganicznej, Politechnika Wrocławska, Wrocław, Poland
| | - Natalia Szulc
- Wydział Podstawowych Problemów Techniki, Katedra Inżynierii Biomedycznej, Politechnika Wrocławska, Wrocław, Poland
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El Khoury Y, Le Breton G, Cunha AV, Jansen TLC, van Wilderen LJGW, Bredenbeck J. Lessons from combined experimental and theoretical examination of the FTIR and 2D-IR spectroelectrochemistry of the amide I region of cytochrome c. J Chem Phys 2021; 154:124201. [PMID: 33810651 DOI: 10.1063/5.0039969] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Amide I difference spectroscopy is widely used to investigate protein function and structure changes. In this article, we show that the common approach of assigning features in amide I difference signals to distinct secondary structure elements in many cases may not be justified. Evidence comes from Fourier transform infrared (FTIR) and 2D-IR spectroelectrochemistry of the protein cytochrome c in the amide I range, in combination with computational spectroscopy based on molecular dynamics (MD) simulations. This combination reveals that each secondary structure unit, such as an alpha-helix or a beta-sheet, exhibits broad overlapping contributions, usually spanning a large part of the amide I region, which in the case of difference absorption experiments (such as in FTIR spectroelectrochemistry) may lead to intensity-compensating and even sign-changing contributions. We use cytochrome c as the test case, as this small electron-transferring redox-active protein contains different kinds of secondary structure units. Upon switching its redox-state, the protein exhibits a different charge distribution while largely retaining its structural scaffold. Our theoretical analysis suggests that the change in charge distribution contributes to the spectral changes and that structural changes are small. However, in order to confidently interpret FTIR amide I difference signals in cytochrome c and proteins in general, MD simulations in combination with additional experimental approaches such as isotope labeling, the insertion of infrared labels to selectively probe local structural elements will be required. In case these data are not available, a critical assessment of previous interpretations of protein amide I 1D- and 2D-IR difference spectroscopy data is warranted.
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Affiliation(s)
- Youssef El Khoury
- Institut für Biophysik, Johann-Wolfgang-Goethe-Universität, Max-von-Laue-Strasse. 1, 60438 Frankfurt am Main, Germany
| | - Guillaume Le Breton
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ana V Cunha
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Thomas L C Jansen
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Luuk J G W van Wilderen
- Institut für Biophysik, Johann-Wolfgang-Goethe-Universität, Max-von-Laue-Strasse. 1, 60438 Frankfurt am Main, Germany
| | - Jens Bredenbeck
- Institut für Biophysik, Johann-Wolfgang-Goethe-Universität, Max-von-Laue-Strasse. 1, 60438 Frankfurt am Main, Germany
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Singh VK, Kumar S, Tapryal S. Aggregation Propensities of Herpes Simplex Virus-1 Proteins and Derived Peptides: An In Silico and In Vitro Analysis. ACS OMEGA 2020; 5:12964-12973. [PMID: 32548480 PMCID: PMC7288601 DOI: 10.1021/acsomega.0c00730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/11/2020] [Indexed: 06/10/2023]
Abstract
Recurrent infections of neurotropic herpes simplex virus-1 (HSV-1) have been implicated in etiology and pathology of Alzheimer's disease (AD). Although protein and peptide aggregation events are at the center of the AD pathophysiology, except a single study where a peptide derived from glycoprotein B of HSV-1 was reported to form β-amyloid-like aggregates, similar investigations with the entire proteome of HSV-1 have not been attempted. In the current study, 70 HSV-1 proteins were screened using bioinformatics tools to identify aggregation-prone candidates. Thereafter, the 20S proteasome cleavage sites within the sequence of the selected proteins were determined using Pcleavage and NetChop algorithms, thereby mimicking a cellular proteasomal activity providing short peptides. Here, we report the biochemical characterization of a 28-residue-long peptide (HSV-1 gK208-235) derived from glycoprotein K of HSV-1. The peptide showed high aggregation propensity and homology to the C-terminus of Aβ1-42 peptide. The aggregates of gK208-235 peptide were characterized by the Congo red and Thioflavin T assays and Fourier transform infrared (FTIR) spectroscopy, and their spheroid oligomeric structure was established by atomic force microscopy (AFM). Furthermore, the aggregates demonstrated dose-dependent cytotoxicity to primary mouse splenocytes. The current findings hypothesize a mechanism by which HSV-1 may contribute to AD, which may be pursued further in the future.
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7
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Jiao D, Liu Y, Liu Y, Zeng R, Hou X, Nie G, Sun L, Fang Z. Preparation of phosphatidylcholine nanovesicles containing bacteriocin CAMT2 and their anti-listerial activity. Food Chem 2020; 314:126244. [PMID: 31982854 DOI: 10.1016/j.foodchem.2020.126244] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 12/10/2019] [Accepted: 01/16/2020] [Indexed: 10/25/2022]
Abstract
A novel bacteriocin CAMT2, produced by Bacillus amyloliquefaciens ZJHD3-06, has potential as a natural biopreservative for the control of food-borne spoilage and pathogenic bacteria. To avoid interaction of CAMT2 with components of food that may adversely impact its antibacterial activity, CAMT2 was encapsulated into nanovesicles prepared from soybean phosphatidylcholine. The encapsulation of CAMT2 exhibited a limited impact on functional structure and crystallinity of bacteriocin CAMT2, but a high anti-listerial activity in agar, and increase its stability in food at refrigeration temperature (4 °C). The results also showed that both encapsulated and free CAMT2 had good anti-listerial effect in skim milk at refrigeration temperature. However, encapsulated CAMT2 performed better than free CAMT2 against Listeria in whole milk. These results showed that nano-encapsulation is an effective method of protecting bacteriocin from fat in milk and retaining its antimicrobial efficacy.
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Affiliation(s)
- Dongdong Jiao
- College of Food Science and Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Marine Food, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang 524088, China
| | - Ying Liu
- College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China
| | - Ying Liu
- College of Food Science and Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Marine Food, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang 524088, China.
| | - Ruchun Zeng
- School of Physics and Telecommunication Engineering, Yulin Normal University, Yulin 537000, China; Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology, Yulin 537000, China
| | - Xiaoqin Hou
- College of Food Science and Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Marine Food, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang 524088, China
| | - Guochao Nie
- School of Physics and Telecommunication Engineering, Yulin Normal University, Yulin 537000, China; Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology, Yulin 537000, China.
| | - Lijun Sun
- College of Food Science and Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Marine Food, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang 524088, China
| | - Zhijia Fang
- College of Food Science and Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Marine Food, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang 524088, China.
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8
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Acharyya A, Ge Y, Wu H, DeGrado WF, Voelz VA, Gai F. Exposing the Nucleation Site in α-Helix Folding: A Joint Experimental and Simulation Study. J Phys Chem B 2019; 123:1797-1807. [PMID: 30694671 DOI: 10.1021/acs.jpcb.8b12220] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
One of the fundamental events in protein folding is α-helix formation, which involves sequential development of a series of helical hydrogen bonds between the backbone C═O group of residues i and the -NH group of residues i + 4. While we now know a great deal about α-helix folding dynamics, a key question that remains to be answered is where the productive helical nucleation event occurs. Statistically, a helical nucleus (or the first helical hydrogen-bond) can form anywhere within the peptide sequence in question; however, the one that leads to productive folding may only form at a preferred location. This consideration is based on the fact that the α-helical structure is inherently asymmetric, due to the specific alignment of the helical hydrogen bonds. While this hypothesis is plausible, validating it is challenging because there is not an experimental observable that can be used to directly pinpoint the location of the productive nucleation process. Therefore, in this study we combine several techniques, including peptide cross-linking, laser-induced temperature-jump infrared spectroscopy, and molecular dynamics simulations, to tackle this challenge. Taken together, our experimental and simulation results support an α-helix folding mechanism wherein the productive nucleus is formed at the N-terminus, which propagates toward the C-terminal end of the peptide to yield the folded structure. In addition, our results show that incorporation of a cross-linker can lead to formation of differently folded conformations, underscoring the need for all-atom simulations to quantitatively assess the proposed cross-linking design.
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Affiliation(s)
- Arusha Acharyya
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Yunhui Ge
- Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Haifan Wu
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Vincent A Voelz
- Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Feng Gai
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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9
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Gagkaeva ZV, Zhukova ES, Grinenko V, Grebenko AK, Sidoruk KV, Voeikova TA, Dressel M, Gorshunov BP. Terahertz-infrared spectroscopy of Shewanella oneidensis MR-1 extracellular matrix. J Biol Phys 2018; 44:401-417. [PMID: 29732506 PMCID: PMC6082806 DOI: 10.1007/s10867-018-9497-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 04/13/2018] [Indexed: 01/30/2023] Open
Abstract
Employing optical spectroscopy we have performed a comparative study of the dielectric response of extracellular matrix and filaments of electrogenic bacteria Shewanella oneidensis MR-1, cytochrome c, and bovine serum albumin. Combining infrared transmission measurements on thin layers with data of the terahertz spectra, we obtain the dielectric permittivity and AC conductivity spectra of the materials in a broad frequency band from a few cm-1 up to 7000 cm-1 in the temperature range from 5 to 300 K. Strong absorption bands are observed in the three materials that cover the range from 10 to 300 cm-1 and mainly determine the terahertz absorption. When cooled down to liquid helium temperatures, the bands in Shewanella oneidensis MR-1 and cytochrome c reveal a distinct fine structure. In all three materials, we identify the presence of liquid bound water in the form of librational and translational absorption bands at ≈ 200 and ≈ 600 cm-1, respectively. The sharp excitations seen above 1000 cm-1 are assigned to intramolecular vibrations.
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Affiliation(s)
- Z V Gagkaeva
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - E S Zhukova
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - V Grinenko
- Institute for Metallic Materials, IFW Dresden, Dresden, Germany
| | - A K Grebenko
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - K V Sidoruk
- Scientific Center of Russian Federation Research Institute for Genetics and Selection of Industrial Microorganisms, Moscow, Russia
| | - T A Voeikova
- Scientific Center of Russian Federation Research Institute for Genetics and Selection of Industrial Microorganisms, Moscow, Russia
| | - M Dressel
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
- Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - B P Gorshunov
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia.
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10
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Muneeswaran G, Kartheeswaran S, Muthukumar K, Karunakaran C. Temperature-dependent conformational dynamics of cytochrome c: Implications in apoptosis. J Mol Graph Model 2017; 79:140-148. [PMID: 29161635 DOI: 10.1016/j.jmgm.2017.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/12/2017] [Accepted: 10/12/2017] [Indexed: 11/29/2022]
Abstract
Heat, electric shock, and burn injuries induce apoptosis by releasing cytochrome c (cyt-c) from mitochondria and by subsequently activating the death protease, caspases-3. During apoptosis, cyt-c undergoes changes in the secondary structure that have been suggested to increase its peroxidase activity. Information about these structural changes will provide better understanding of the apoptotic mechanism. Hence, temperature-dependent conformational dynamics of cyt-c has been investigated through molecular dynamics (MD) simulations to explain the structural changes and to correlate them with its apoptotic behavior. We observe that, at lower temperatures (223, 248, and 300K), the secondary structure of cyt-c, remains stable, while at higher temperatures (323, 373, 423, and 473K), the secondary structural regions change significantly. Further, our MD results indicate that these structural changes are mainly localized on α-helices, turns, β-sheets, and important loops that were involved in the stabilization of the heme conformation. This conformational transition between specific regions of secondary structure of cyt-c directly affects the electron tunneling properties of the proteins as observed experimentally. We quantify and compare these changes and explain that the temperature plays a vital role in assuring the structural stability of cyt-c and thus its functions. Our findings from this MD study reproduce experimental results at high temperatures and provide evidence for the alteration of the heme through the disruption of the H-bonding interactions between specific regions of cyt-c, thereby enhancing its peroxidase activity which plays a crucial role in the apoptotic process.
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Affiliation(s)
- Gurusamy Muneeswaran
- Biomedical Research Lab, Department of Chemistry, VHNSN College (Autonomous), Virudhunagar, 626 001, Tamilnadu, India; Department of Chemistry, School of Advanced Sciences, Kalasalingam Academy of Research and Education, Krishnanakoil, 626 126, Tamil Nadu, India
| | - Subramanian Kartheeswaran
- Department of Master of Computer Applications, School of Computing, Kalasalingam Academy of Research and Education, Krishnanakoil, 626 126, Tamil Nadu, India
| | | | - Chandran Karunakaran
- Biomedical Research Lab, Department of Chemistry, VHNSN College (Autonomous), Virudhunagar, 626 001, Tamilnadu, India.
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11
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Zhang M, Zhang M, Liu Y, Chen Y, Zhang K, Wang C, Zhao X, Zhou C, Gao J, Xie X, Zheng D, Zhao G. DFT/TDDFT theoretical investigation on the excited-state intermolecular hydrogen bonding interactions, photoinduced charge transfer, and vibrational spectroscopic properties of deprotonated deoxyadenosine monophosphate [dAMP-H] − anion in aqueous solution: Upon photoexcitation of hydrogen-bonded model complexes [dAMP-H] − –nH 2 O ( n = 0, 1, 2, 3, 4). J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.07.120] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Muneeswaran G, Kartheeswaran S, Muthukumar K, Dharmaraj CD, Karunakaran C. Effects of different solvents on the conformations of apoptotic cytochrome c: Structural insights from molecular dynamics simulation. J Mol Graph Model 2017; 76:234-241. [DOI: 10.1016/j.jmgm.2017.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 01/30/2023]
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13
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Lin CW, Gai F. Microscopic nucleation and propagation rates of an alanine-based α-helix. Phys Chem Chem Phys 2017; 19:5028-5036. [PMID: 28165082 PMCID: PMC5359971 DOI: 10.1039/c6cp08924k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An infrared temperature-jump (T-jump) study by Huang et al. (Proc. Natl. Acad. Sci. U. S. A., 2002, 99, 2788-2793) showed that the conformational relaxation kinetics of an alanine-based α-helical peptide depend not only on the final temperature (Tf) but also on the initial temperature (Ti) when Tf is fixed. Their finding indicates that the folding free energy landscape of this peptide is non-two-state like, allowing for the population of conformational ensembles with different helical lengths and relaxation times in the temperature range of the experiment. Because α-helix folding involves two fundamental events, nucleation and propagation, the results of Huang et al. thus present a unique opportunity to determine their rate constants - a long-sought goal in the study of the helix-coil transition dynamics. Herein, we capitalize on this notion and develop a coarse-grained kinetic model to globally fit the thermal unfolding curve and T-jump kinetic traces of this peptide. Using this strategy, we are able to explicitly determine the microscopic rate constants of the kinetic steps encountered in the nucleation and propagation processes. Our results reveal that the time taken to form one α-helical turn (i.e., an α-helical segment with one helical hydrogen bond) is about 315 ns, whereas the time taken to elongate this nucleus by one residue (or backbone unit) is 5.9 ns, depending on the position of the residue.
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Affiliation(s)
- Chun-Wei Lin
- Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104, USA.
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104, USA.
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14
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Zeng L, Wu L, Liu L, Jiang X. Analyzing Structural Properties of Heterogeneous Cardiolipin-Bound Cytochrome C and Their Regulation by Surface-Enhanced Infrared Absorption Spectroscopy. Anal Chem 2016; 88:11727-11733. [DOI: 10.1021/acs.analchem.6b03360] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Li Zeng
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lie Wu
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Li Liu
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Xiue Jiang
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
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15
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Yang J, Siriwardena A, Boukherroub R, Ozanam F, Szunerits S, Gouget-Laemmel AC. A quantitative method to discriminate between non-specific and specific lectin–glycan interactions on silicon-modified surfaces. J Colloid Interface Sci 2016; 464:198-205. [DOI: 10.1016/j.jcis.2015.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/07/2015] [Accepted: 11/10/2015] [Indexed: 01/13/2023]
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Li D, Li Y, Li H, Wu X, Yu Q, Weng Y. A Q-switched Ho:YAG laser assisted nanosecond time-resolved T-jump transient mid-IR absorbance spectroscopy with high sensitivity. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:053105. [PMID: 26026512 DOI: 10.1063/1.4921473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm(-1) as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10(-4) ΔOD for a single wavelength detection, and 2 × 10(-4) ΔOD for spectral detection in amide I' region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.
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Affiliation(s)
- Deyong Li
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunliang Li
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hao Li
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xianyou Wu
- Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Qingxu Yu
- School of Physics and Optoelectronic Technology, Dalian University of Technology, No. 2, Linggong Road, Dalian 116023, China
| | - Yuxiang Weng
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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17
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Romanelli SM, Hartnett JW, Banerjee IA. Effects of amide side chains on nanoassembly formation and gelation of Fmoc–valine conjugates. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2014.10.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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Yang J, Chazalviel JN, Siriwardena A, Boukherroub R, Ozanam F, Szunerits S, Gouget-Laemmel AC. Quantitative assessment of the multivalent protein-carbohydrate interactions on silicon. Anal Chem 2014; 86:10340-9. [PMID: 25216376 DOI: 10.1021/ac502624m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A key challenge in the development of glycan arrays is that the sensing interface be fabricated reliably so as to ensure the sensitive and accurate analysis of the protein-carbohydrate interaction of interest, reproducibly. These goals are complicated in the case of glycan arrays as surface sugar density can influence dramatically the strength and mode of interaction of the sugar ligand at any interface with lectin partners. In this Article, we describe the preparation of carboxydecyl-terminated crystalline silicon (111) surfaces onto which are grafted either mannosyl moieties or a mixture of mannose and spacer alcohol molecules to provide "diluted" surfaces. The fabrication of the silicon surfaces was achieved efficiently through a strategy implicating a "click" coupling step. The interactions of these newly fabricated glycan interfaces with the lectin, Lens culinaris, have been characterized using quantitative infrared (IR) spectroscopy in the attenuated total geometry (ATR). The density of mannose probes and lectin targets was precisely determined for the first time by the aid of special IR calibration experiments, thus allowing for the interpretation of the distribution of mannose and its multivalent binding with lectins. These experimental findings were accounted for by numerical simulations of lectin adsorption.
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Affiliation(s)
- Jie Yang
- Physique de la Matière Condensée, Ecole Polytechnique-CNRS , 91128 Palaiseau, France
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19
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Meadows CW, Ou R, Klinman JP. Picosecond-resolved fluorescent probes at functionally distinct tryptophans within a thermophilic alcohol dehydrogenase: relationship of temperature-dependent changes in fluorescence to catalysis. J Phys Chem B 2014; 118:6049-61. [PMID: 24892947 PMCID: PMC4056859 DOI: 10.1021/jp500825x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two single-tryptophan variants were generated in a thermophilic alcohol dehydrogenase with the goal of correlating temperature-dependent changes in local fluorescence with the previously demonstrated catalytic break at ca. 30 °C (Kohen et al., Nature 1999, 399, 496). One tryptophan variant, W87in, resides at the active site within van der Waals contact of bound alcohol substrate; the other variant, W167in, is a remote-site surface reporter located >25 Å from the active site. Picosecond-resolved fluorescence measurements were used to analyze fluorescence lifetimes, time-dependent Stokes shifts, and the extent of collisional quenching at Trp87 and Trp167 as a function of temperature. A subnanosecond fluorescence decay rate constant has been detected for W87in that is ascribed to the proximity of the active site Zn(2+) and shows a break in behavior at 30 °C. For the remainder of the reported lifetime measurements, there is no detectable break between 10 and 50 °C, in contrast with previously reported hydrogen/deuterium exchange experiments that revealed a temperature-dependent break analogous to catalysis (Liang et al., Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 9556). We conclude that the motions that lead to the rigidification of ht-ADH below 30 °C are likely to be dominated by global processes slower than the picosecond to nanosecond motions measured herein. In the case of collisional quenching of fluorescence by acrylamide, W87in and W167in behave in a similar manner that resembles free tryptophan in water. Stokes shift measurements, by contrast, show distinctive behaviors in which the active-site tryptophan relaxation is highly temperature-dependent, whereas the solvent-exposed tryptophan's dynamics are temperature-independent. These data are concluded to reflect a significantly constrained environment surrounding the active site Trp87 that both increases the magnitude of the Stokes shift and its temperature-dependence. The results are discussed in the context of spatially distinct differences in enthalpic barriers for protein conformational sampling that may be related to catalysis.
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Affiliation(s)
- Corey W Meadows
- Department of Chemistry, ‡Department of Molecular and Cell Biology, and the §California Institute for Quantitative Biosciences, University of California, Berkeley , Berkeley, California 94720, United States
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20
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Thermal-triggerd proteinquake leads to disassembly of DegP hexamer as an imperative activation step. Sci Rep 2014; 4:4834. [PMID: 24776652 PMCID: PMC4003476 DOI: 10.1038/srep04834] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 04/11/2014] [Indexed: 11/23/2022] Open
Abstract
The Escherichia coli DegP has been reported to function both as molecular chaperone and protease for the quality control of outer membrane protein biogenesis. Activation of the inactive DegP hexamers was believed to occur via their disassembly into trimeric units and subsequent reassembly into larger oligomers (12-mers and 24-mers). Here, we analyzed the thermal stability and the unfolding dynamics of the different secondary structure components of the DegP hexamers using Fourier transform infrared spectroscopy and temperature-jump nanosecond time-resolved IR difference absorbance spectroscopy. We found that the interfacial secondary structure components possess a degreed thermal stability, with the disassembly of the DegP hexamers follows a “proteinquake” manner, such that the fully exposed parts of the interfacial β-sheets serving as the temperature sensor and epicenter to drive the sequential unfolding/disassembly process that finishes within about 134 ns at room temperature.
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21
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Cheng CL, Zhang MZ, Zhao GJ. Mechanical stability and thermal conductivity of β-barrel in green fluorescent protein by steered molecular dynamics. RSC Adv 2014. [DOI: 10.1039/c3ra42679c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Li S, Yu Y, Li D, He X, Bao Y, Weng Y. Thermal‐induced Unfolding of β‐Crystallin and Disassembly of its Oligomers Revealed by Temperature‐Jump Time‐Resolved Infrared Spectroscopy. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/06/739-746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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23
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Zaragoza A, Teruel JA, Aranda FJ, Ortiz A. Interaction of a trehalose lipid biosurfactant produced by Rhodococcus erythropolis 51T7 with a secretory phospholipase A2. J Colloid Interface Sci 2013; 408:132-7. [DOI: 10.1016/j.jcis.2013.06.073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 06/27/2013] [Accepted: 06/29/2013] [Indexed: 11/16/2022]
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24
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Zhang Y, Li B, Xu Y, Li H, Li S, Zhang D, Mao Z, Guo S, Yang C, Weng Y, Chong K. The cyclophilin CYP20-2 modulates the conformation of BRASSINAZOLE-RESISTANT1, which binds the promoter of FLOWERING LOCUS D to regulate flowering in Arabidopsis. THE PLANT CELL 2013; 25:2504-21. [PMID: 23897924 PMCID: PMC3753379 DOI: 10.1105/tpc.113.110296] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 07/01/2013] [Accepted: 07/14/2013] [Indexed: 05/20/2023]
Abstract
Brassinosteroids (BRs) regulate many physiological processes during plant development, including flowering. However, little is known about the components of BR signaling that mediate flowering. Here, we report that BRASSINAZOLE-RESISTANT1 (BZR1), the conformation of which is altered by a cyclophilin (CYP20-2), binds cis-elements in the FLOWERING LOCUS D (FLD) promoter to regulate flowering. Both bzr1-1D and fld-4 showed delayed flowering. Electrophoretic mobility shift assay and chromatin immunoprecipitation revealed that BZR1 bound to a putative BR response cis-element and suppressed the expression of FLD. Overexpression of FLD partially rescued the late flowering of pBZR1:mBZR1(Pro234-Leu)-CFP (mx3). Yeast two-hybrid and pull-down assays demonstrated that BZR1 interacts with CYP20-2. Arabidopsis thaliana CYP20-2 had greater peptidyl-prolyl cis-trans isomerase activity than did wheat (Triticum aestivum) CYP20-2. Fourier transform infrared spectroscopy revealed conformation changes in BZR1, dependent on interaction with CYP20-2. Due to differences in activity and substrate preference between CYP20-2 proteins from wheat and Arabidopsis, At-CYP20-2-overexpressing lines showed earlier flowering, whereas Ta CYP20-2 lines flowered later. Immunoblot and chromatin immunoprecipitation assays showed that histone H3 trimethyl Lys4 and H3 acetylation levels were negatively correlated with the transcription of FLD (a putative histone demethylase) in various lines. Therefore, a conformational change of BZR1 mediated by CYP20-2 causes altered flowering through modulation of FLD expression.
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Affiliation(s)
- Yuanyuan Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Beibei Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yunyuan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Heng Li
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shanshan Li
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dajian Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Mao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Siyi Guo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Chunhong Yang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yuxiang Weng
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Address correspondence to
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25
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Zaragoza A, Teruel JA, Aranda FJ, Marqués A, Espuny MJ, Manresa Á, Ortiz A. Interaction of a Rhodococcus sp. trehalose lipid biosurfactant with model proteins: thermodynamic and structural changes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:1381-90. [PMID: 22172005 DOI: 10.1021/la203879t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
One major application of surfactants is to prevent aggregation during various processes of protein manipulation. In this work, a bacterial trehalose lipid (TL) with biosurfactant activity, secreted by Rhodococcus sp., has been identified and purified. The interactions of this glycolipid with selected model proteins have been studied by using differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, isothermal titration calorimetry (ITC), and fluorescence spectroscopy. Bovine serum albumin (BSA) and cytochrome c (Cyt-c) have been chosen because of their quite different secondary structures: BSA contains essentially no β-sheets and an average 66% α-helix, whereas Cyt-c possesses up to 25% β-sheets and up to 45% α-helical structure. Differential scanning calorimetry shows that addition of TL to BSA at concentrations below the critical micelle concentration (cmc) shifts the thermal unfolding temperature to higher values. FTIR indicates that TL does not alter the secondary structure of native BSA, but the presence of TL protects the protein toward thermal denaturation, mainly by avoiding formation of β-aggregates. Studies on the intrinsic Trp fluorescence of BSA show that addition of TL to the native protein results in conformational changes. BSA unfolding upon thermal denaturation in the absence of TL makes the Trp residues less accessible to the quencher, as shown by a decrease in the value of Stern-Volmer dynamic quenching constant, whereas denaturation in the presence of the biosurfactant prevents unfolding, in agreement with FTIR results. In the case of Cyt-c, interaction with TL gives rise to a new thermal denaturation transition, as observed by DSC, at temperatures below that of the native protein, therefore facilitating thermal unfolding. Binding of TL to native BSA and Cyt-c, as determined by ITC, suggests a rather nonspecific interaction of the biosurfactant with both proteins. FTIR indicates that TL slightly modifies the secondary structure of native Cyt-c, but protein denaturation in the presence of TL results in a higher proportion of β-aggregates than in its absence (20% vs 3.9%). The study of Trp fluorescence upon TL addition to Cyt-c results in a completely opposite scenario to that described above for BSA. In this case, addition of TL considerably increases the value of the dynamic quenching constant, both in native and denatured protein; that is, the interaction with the glycolipid induces conformational changes which facilitate the exposure of Trp residues to the quencher. Considering the structures of both proteins, it could be derived that the characteristics of TL interactions, either promoting or avoiding thermal unfolding, are highly dependent on the protein secondary structure. Our results also suggest the rather unspecific nature of these interactions. These might well involve protein hydrophobic domains which, being buried into the protein native structures, become exposed upon thermal unfolding.
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Affiliation(s)
- Ana Zaragoza
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia , E-30100 Murcia, Spain
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26
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Ye S, Markelz A. Hydration Effects on Energy Relaxation of Ferric Cytochrome C Films after Soret-Band Photoexcitation. J Phys Chem B 2010; 114:15151-7. [DOI: 10.1021/jp104217j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shuji Ye
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China 230026, and Department of Physics, University at Buffalo, SUNY, 239 Fronczak Hall, Buffalo, New York 14260-1500, United States
| | - Andrea Markelz
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China 230026, and Department of Physics, University at Buffalo, SUNY, 239 Fronczak Hall, Buffalo, New York 14260-1500, United States
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27
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Zang C, Stevens JA, Link JJ, Guo L, Wang L, Zhong D. Ultrafast proteinquake dynamics in cytochrome c. J Am Chem Soc 2010; 131:2846-52. [PMID: 19203189 DOI: 10.1021/ja8057293] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report here our systematic studies of the heme dynamics and induced protein conformational relaxations in two redox states of ferric and ferrous cytochrome c upon femtosecond excitation. With a wide range of probing wavelengths from the visible to the UV and a site-directed mutation we unambiguously determined that the protein dynamics in the two states are drastically different. For the ferrous state the heme transforms from 6-fold to 5-fold coordination with ultrafast ligand dissociation in less than 100 fs, followed by vibrational cooling within several picoseconds, but then recombining back to its original 6-fold coordination in 7 ps. Such impulsive bond breaking and late rebinding generate proteinquakes and strongly perturb the local heme site and shake global protein conformation, which were found to completely recover in 13 and 42 ps, respectively. For the ferric state the heme however maintains its 6-fold coordination. The dynamics mainly occur at the local site, including ultrafast internal conversion in hundreds of femtoseconds, vibrational cooling on the similar picosecond time scale, and complete ground-state recovery in 10 ps, and no global conformation relaxation was observed.
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Affiliation(s)
- Chen Zang
- Department of Physics, Program of Biophysics, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210, USA
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28
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Thermal-induced dissociation and unfolding of homodimeric DsbC revealed by temperature-jump time-resolved infrared spectra. Biophys J 2010; 97:2811-9. [PMID: 19917236 DOI: 10.1016/j.bpj.2009.08.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 08/19/2009] [Accepted: 08/27/2009] [Indexed: 11/23/2022] Open
Abstract
The thermal stability of DsbC, a homodimeric protein disulfide isomerase in prokaryotic periplasm, has been studied by using temperature-dependent Fourier transformation infrared and time-resolved infrared spectroscopy coupled with temperature-jump initiation. The infrared absorbance thermal titration curves for thermal-induced unfolding of DsbC in D(2)O exhibit a three-state transition with the first transition midpoint temperature at 37.1 +/- 1.1 degrees C corresponding to dissociation, and the second at >74.5 degrees C corresponding to global unfolding and aggregation. The dissociation midpoint temperature of DsbC in phosphate buffer shifts to 49.2 +/- 0.7 degrees C. Temperature-jump time-resolved infrared spectra in D(2)O shows that DsbC dissociates into the corresponding germinate monomeric encounter pair with a time constant of 40 +/- 10 ns independent of the protein concentration and 77% of the newly formed monomeric encounter pair undergoes further coil to helix/loop transition with a time constant of 160 +/- 10 ns. The encounter pair is expected to proceed with further dissociation into monomers. The dissociation of DsbC is confirmed by size-exclusion chromatography and subunit hybridization. The in vivo oxidase activity of DsbC attributed to the monomer has also been observed by using cadmium sensitivity and the oxidative state of beta-lactamase.
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29
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Pethica BA. The thermodynamics of protein folding: a critique of widely used quasi-thermodynamic interpretations and a restatement based on the Gibbs–Duhem relation and consistent with the Phase Rule. Phys Chem Chem Phys 2010; 12:7445-56. [DOI: 10.1039/b920960c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Li H, Xu YY, Weng YX. Infrared Absorption Intensity Analysis as a New Tool for Investigation of Salt Effect on Proteins. CHINESE J CHEM PHYS 2009. [DOI: 10.1088/1674-0068/22/06/556-562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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