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RAVI SINGH K, Santhosh C, Swaroop TR, Sadashiva MP. Regioselective synthesis of 2,5- and 4,5-disubstituted thiazoles via cyclization of 2-oxo-2-(amino)ethanedithioates with isocyanides. Org Biomol Chem 2022; 20:5771-5778. [DOI: 10.1039/d2ob00837h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The regioselective synthesis of 2-(methylthio)-N-aryl/alkylthiazole-5-carboxamides and ethyl-5-(aryl/alkyl carbamoyl)thiazole-4-carboxylates by base induced cyclization of methyl-2-oxo-2-(amino)ethanedithioates with TosMIC and ethylisocyanoacetate respectively in high yield. The regioisomeric product was confirmed by X-ray diffraction...
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Muhammed Shameem K, Dhanada V, Harikrishnan S, George SD, Kartha V, Santhosh C, Unnikrishnan V. Echelle LIBS-Raman system: A versatile tool for mineralogical and archaeological applications. Talanta 2020; 208:120482. [DOI: 10.1016/j.talanta.2019.120482] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 11/28/2022]
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Muhammed Shameem KM, Dhanada VS, Unnikrishnan VK, George SD, Kartha VB, Santhosh C. A hyphenated echelle LIBS-Raman system for multi-purpose applications. Rev Sci Instrum 2018; 89:073108. [PMID: 30068097 DOI: 10.1063/1.5024966] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have developed and standardized a novel hybrid laser-induced breakdown spectroscopy (LIBS)-Raman system using a single pulsed laser and a high-resolution intensified charge coupled device coupled echelle spectrograph. LIBS and Raman spectroscopy are highly complementary techniques which yield elemental and molecular information. Both techniques share an apparently similar instrumental configuration but need entirely different requirements like spectral range covered, resolution, and light-gathering efficiencies. There are thus many challenges to be faced in developing a combined system. In the present work, we show that an echelle spectrograph combined with a compact Q-switched Nd:YAG laser operating at 532 nm as an excitation source in a portable configuration can be efficiently used for such multi-purpose spectroscopy. Atomic and molecular emissions from the sample surface have been recorded in a gated mode using this setup. Compared to conventional spectrographs, echelle provides simultaneous broad bandpass (250-900 nm) and better spectral resolution at an extremely small fixed slit width of 10 × 50 μm without moving the dispersive elements. The echelle-based hyphenated system provides fast and reliable analysis of materials with combined atomic and molecular spectra of the same spot with better reliability. In this paper, we discuss the optimization of various instrumental parameters and optical components of this hyphenated system using a medium Raman cross section sample, CaCO3. The feasibility of single shot LIBS-Raman measurement capabilities of echelle has also been demonstrated using the developed system.
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Affiliation(s)
- K M Muhammed Shameem
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
| | - V S Dhanada
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
| | - V K Unnikrishnan
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
| | - Sajan D George
- Centre for Applied Nanosciences, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
| | - V B Kartha
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
| | - C Santhosh
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
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Muhammed Shameem KM, Chawla A, Mallya M, Barik BK, Unnikrishnan VK, Kartha VB, Santhosh C. Laser-induced breakdown spectroscopy-Raman: An effective complementary approach to analyze renal-calculi. J Biophotonics 2018; 11:e201700271. [PMID: 29411942 DOI: 10.1002/jbio.201700271] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/02/2018] [Indexed: 05/24/2023]
Abstract
Presence of renal-calculi (kidney stones) in human urethra is being increasingly diagnosed over the last decade and is considered as one of the most painful urological disorders. Accurate analysis of such stones plays a vital role in the evaluation of urolithiasis patients and in turn helps the clinicians toward exact etiologies. Two highly complementary laser-based analytical techniques; laser-induced breakdown spectroscopy (LIBS) and micro-Raman spectroscopy have been used to identify the chemical composition of different types of renal-calculi. LIBS explores elemental characteristics while Raman spectroscopy provides molecular details of the sample. This complete information on the sample composition might help clinicians to identify the key aspects of the formation of kidney stones, hence assist in therapeutic management and to prevent recurrence. The complementarity of both techniques has been emphasized and discussed. LIBS spectra of different types of stones suggest the probable composition of it by virtue of the major, minor and trace elements detected from the sample. However, it failed to differentiate the crystalline form of different hydrates of calcium oxalate stone. This lacuna was overcome by the use of Raman spectroscopy and these results are compared with conventional chemical analysis.
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Affiliation(s)
- K M Muhammed Shameem
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal, 576 104, India
| | - Arun Chawla
- Department of Urology, Kasturba Medical College, Manipal, India
| | | | | | - V K Unnikrishnan
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal, 576 104, India
| | - V B Kartha
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal, 576 104, India
| | - C Santhosh
- Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal, 576 104, India
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Pujar G, Wari M, Steffi B, Varsha H, Kavita B, Yohannan Panicker C, Santhosh C, Patil A, Inamdar SR. A combined experimental and computational investigation of solvatochromism of nonpolar laser dyes: Evaluation of ground and singlet excited-state dipole moments. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.08.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Shameem KMM, Choudhari KS, Bankapur A, Kulkarni SD, Unnikrishnan VK, George SD, Kartha VB, Santhosh C. A hybrid LIBS-Raman system combined with chemometrics: an efficient tool for plastic identification and sorting. Anal Bioanal Chem 2017; 409:3299-3308. [PMID: 28321503 DOI: 10.1007/s00216-017-0268-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [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: 10/18/2016] [Revised: 02/12/2017] [Accepted: 02/20/2017] [Indexed: 11/30/2022]
Abstract
Classification of plastics is of great importance in the recycling industry as the littering of plastic wastes increases day by day as a result of its extensive use. In this paper, we demonstrate the efficacy of a combined laser-induced breakdown spectroscopy (LIBS)-Raman system for the rapid identification and classification of post-consumer plastics. The atomic information and molecular information of polyethylene terephthalate, polyethylene, polypropylene, and polystyrene were studied using plasma emission spectra and scattered signal obtained in the LIBS and Raman technique, respectively. The collected spectral features of the samples were analyzed using statistical tools (principal component analysis, Mahalanobis distance) to categorize the plastics. The analyses of the data clearly show that elemental information and molecular information obtained from these techniques are efficient for classification of plastics. In addition, the molecular information collected via Raman spectroscopy exhibits clearly distinct features for the transparent plastics (100% discrimination), whereas the LIBS technique shows better spectral feature differences for the colored samples. The study shows that the information obtained from these complementary techniques allows the complete classification of the plastic samples, irrespective of the color or additives. This work further throws some light on the fact that the potential limitations of any of these techniques for sample identification can be overcome by the complementarity of these two techniques. Graphical Abstract ᅟ.
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Affiliation(s)
- K M Muhammed Shameem
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - Khoobaram S Choudhari
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - Aseefhali Bankapur
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - Suresh D Kulkarni
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - V K Unnikrishnan
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India.
| | - Sajan D George
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - V B Kartha
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
| | - C Santhosh
- Department of Atomic and Molecular Physics, Manipal University, LG-01, AB-05 MIT Campus Manipal, Manipal, 576 104, Karnataka, India
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Santhosh C, James A, T M, Saranya M, Ramachandran R, Felix S, T M, Velmurugan V, Grace A. Solvothermal Preparation of Graphene Supported Mn Ferrites and its Photocatalytic Activity. ACTA ACUST UNITED AC 2013. [DOI: 10.2174/22106812112029990007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Harish C, Sreeharsha VS, Santhosh C, Ramachandran R, Saranya M, Vanchinathan TM, Govardhan K, Grace AN. Synthesis of Polyaniline/Graphene Nanocomposites and Its Optical, Electrical and Electrochemical Properties. ACTA ACUST UNITED AC 2013. [DOI: 10.1166/asem.2013.1237] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Unnikrishnan VK, Choudhari KS, Kulkarni SD, Nayak R, Kartha VB, Santhosh C. Analytical predictive capabilities of Laser Induced Breakdown Spectroscopy (LIBS) with Principal Component Analysis (PCA) for plastic classification. RSC Adv 2013. [DOI: 10.1039/c3ra44946g] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Patil A, Choudhari KS, Prabhu V, Unnikrishnan VK, Bhat S, Pai KM, Kartha VB, Santhosh C. Highly Sensitive High Performance Liquid Chromatography-Laser Induced Fluorescence for Proteomics Applications. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/643979] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This paper describes the sensitivity study and performance evaluation of high-performance liquid chromatography-laser-induced fluorescence detection (HPLC-LIF) system assembled in our laboratory for proteomics applications. The limits of Detection (LOD) of several serum proteins have been estimated with this instrument and are found to be much lower compared to other commonly used proteomics techniques like SELDI, MALDI, 2-D-SDS-PAGE, and so forth. Techniques for improving the LOD still further with similar setup are briefly discussed. Using the system, protein profiles of serum in normal, malignant, and premalignant conditions were recorded for different malignancy situations.
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Affiliation(s)
- Ajeetkumar Patil
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 567104, India
| | - K. S. Choudhari
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 567104, India
| | - Vijendra Prabhu
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 567104, India
| | - V. K. Unnikrishnan
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 567104, India
| | - Sujatha Bhat
- Department of Microbiology, KMC International Center, Manipal 567104, India
| | - Keerthilatha M. Pai
- Department of Oral Medicine and Radiology, Manipal College of Dental Sciences, Manipal 567104, India
| | | | - C. Santhosh
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 567104, India
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Muneendra Prasad A, Santhosh C, Nirmala Grace A. Carbon nanotubes and polyaniline supported Pt nanoparticles for methanol oxidation towards DMFC applications. Appl Nanosci 2012. [DOI: 10.1007/s13204-012-0061-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Bhat S, Patil A, Rai L, Kartha V, Santhosh C. Protein profile analysis of cellular samples from the cervix for the objective diagnosis of cervical cancer using HPLC-LIF. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:3225-30. [DOI: 10.1016/j.jchromb.2010.09.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/02/2010] [Accepted: 09/24/2010] [Indexed: 11/25/2022]
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Zachariah E, Bankapur A, Santhosh C, Valiathan M, Mathur D. Probing oxidative stress in single erythrocytes with Raman Tweezers. Journal of Photochemistry and Photobiology B: Biology 2010; 100:113-6. [PMID: 20561796 DOI: 10.1016/j.jphotobiol.2010.05.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 05/22/2010] [Accepted: 05/25/2010] [Indexed: 02/05/2023]
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Karemore G, Mullick JB, Sujatha R, Nielsen M, Santhosh C. Classification of protein profiles using fuzzy clustering techniques: an application in early diagnosis of oral, cervical and ovarian cancer. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2010:6361-6364. [PMID: 21096693 DOI: 10.1109/iembs.2010.5627292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Present study has brought out a comparison of PCA and fuzzy clustering techniques in classifying protein profiles (chromatogram) of homogenates of different tissue origins: Ovarian, Cervix, Oral cancers, which were acquired using HPLC-LIF (High Performance Liquid Chromatography-Laser Induced Fluorescence) method developed in our laboratory. Study includes 11 chromatogram spectra each from oral, cervical, ovarian cancers as well as healthy volunteers. Generally multivariate analysis like PCA demands clear data that is devoid of day-to-day variation, artifacts due to experimental strategies, inherent uncertainty in pumping procedure which is very common activities during HPLC-LIF experiment. Under these circumstances we demonstrate how fuzzy clustering algorithm like Gath Geva followed by Sammon mapping outperform PCA mapping in classifying various cancers from healthy spectra with classification rate up to 95 % from 60%. Methods are validated using various clustering indexes and shows promising improvement in developing optical pathology like HPLC-LIF for early detection of various cancers in all uncertain conditions with high sensitivity and specificity.
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Affiliation(s)
- Gopal Karemore
- University of Copenhagen and Nordic Bioscience Imaging A/S, Herlev Hovedgade 203, 2730, Denmark.
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Singh RK, Naik SK, Gupta L, Balakrishnan S, Santhosh C, Pai KM. Hybrid SVM - Random Forest classication system for oral cancer screening using LIF spectra. ACTA ACUST UNITED AC 2008. [DOI: 10.1109/icpr.2008.4761357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Naik SK, Gupta L, Mittal C, Balakrishnan S, Rath SP, Santhosh C, Pai KM. Optical screening of oral cancer: technology for emerging markets. ACTA ACUST UNITED AC 2007; 2007:2807-10. [PMID: 18002578 DOI: 10.1109/iembs.2007.4352912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Oral cancer is the sixth most common cancer in the world. It is one of the most prevalent cancers in the developing countries of South Asia accounting for one third of the world burden. Sixty percent of the cancers are advanced by the time they are detected. Two methods of optical spectroscopy for detection of oral cancer have been discussed here. These methods are simple, easy to handle and non-invasive. The evaluation of the data is done automatically using pattern recognition techniques, making the screening subjective.
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Nayak GS, Kamath S, Pai KM, Sarkar A, Ray S, Kurien J, D'Almeida L, Krishnanand BR, Santhosh C, Kartha VB, Mahato KK. Principal component analysis and artificial neural network analysis of oral tissue fluorescence spectra: Classification of normal premalignant and malignant pathological conditions. Biopolymers 2006; 82:152-66. [PMID: 16470821 DOI: 10.1002/bip.20473] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pulsed laser-induced autofluorescence spectroscopic studies of pathologically certified normal, premalignant, and malignant oral tissues were carried out at 325 nm excitation. The spectral analysis and classification for discrimination among normal, premalignant, and malignant conditions were performed using principal component analysis (PCA) and artificial neural network (ANN) separately on the same set of spectral data. In case of PCA, spectral residuals, Mahalanobis distance, and scores of factors were used for discrimination among normal, premalignant, and malignant cases. In ANN, parameters like mean, spectral residual, standard deviation, and total energy were used to train the network. The ANN used in this study is a classical multiplayer feed-forward type with a back-propagation algorithm for the training of the network. The specificity and sensitivity were determined in both classification schemes. In the case of PCA, they are 100 and 92.9%, respectively, whereas for ANN they are 100 and 96.5% for the data set considered.
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Affiliation(s)
- G S Nayak
- Department of Electronics and Communication, MIT, Manipal, India
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Abstract
Cation-pi interactions play an important role in the stability of protein structures. In this work, we have analyzed the influence of cation-pi interactions in DNA binding proteins. We observed cation-pi interactions in 45 out of 62 DNA binding proteins and there is no significant correlation between the number of amino acid residues and number of cation-pi interactions. These interactions are mainly formed by long-range contacts, and the role of short and medium-range contacts is minimal. The preference of Arg is higher than Lys to form cation-pi interactions. The pair-wise cation-pi interaction energy between aromatic and positively charged residues shows that Arg-Tyr energy is the strongest among the possible six pairs. The structural analysis of cation-pi interaction forming residues shows that Lys, Trp, and Tyr prefer to be in the binding site of protein-DNA complexes. Further, the accessible surface areas of cation-pi interaction forming cationic residues are significantly less than that of other residues. The preference of cation-pi interaction forming residues in different secondary structures shows that Lys prefers to be in strand and Phe prefers to be in turn regions. The results obtained in the present study will be useful in understanding the contribution of cation-pi interactions to the stability and specificity of protein-DNA complexes.
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Affiliation(s)
- M Michael Gromiha
- Computational Biology Research Center (CBRC), National Institute of Advanced Industrial Science and Technology (AIST), Aomi Frontier Building 17F, 2-43 Aomi, Koto-ku, Tokyo 135-0064, Japan.
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Abstract
Elucidating the factors responsible for exhibiting extreme thermal stability of thermophilic proteins is very important for an understanding of the mechanism of protein stability, as well as to design stable proteins. In this work, we have analyzed the influence of cation-pi interactions to enhance the stability from mesophilic to thermophilic proteins. The favorable residue pairs forming such a system of interactions have been brought out. We found that the Tyr has a greater number of such interactions with Lys in thermophilic proteins. Specifically, the same Lys would experience a greater number of cation-pi interactions with several Tyr residues in thermophiles. On the other hand, the influence of Phe in making cation-pi interactions is higher in mesophiles than in thermophiles. Further, a network of cation-pi interactions are maintained by Lys in thermophiles, whereas Arg plays a major role in mesophilic proteins. Moreover, atoms that have a substantial positive charge in both Lys and Arg make a more significant contribution for cation-pi interactions than do cationic group atoms.
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Affiliation(s)
- M Michael Gromiha
- Computational Biology Research Center (CBRC), AIST, 2-41-6 Aomi, Koto-ku, Tokyo 135-0064, Japan.
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Santhosh C, Mishra PC. Molecular electrostatic potential mapping and structure-activity relationship for 3-methoxy flavones. Indian J Biochem Biophys 1996; 33:458-64. [PMID: 9219430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Molecular electrostatic potential (MEP) maps of certain 3-methoxy flavone derivatives having different anti-picornavirus activities have been studied. Geometries of the molecules were optimised and charge distributions computed using the AM1 molecular orbital method. Hybridization displacement charges (HDC) were combined with the Löwdin charge distributions to compute the MEP maps. Reliability of the method of computing MEP maps was tested by studying certain other molecules for which ab initio MEP results are available. The anti-picornavirus activities of the flavones have been shown to be related with negative MEP values in two regions, one near the 3-methoxy group and another in a diagonally opposite region near the substituent attached to the C7 atom of the molecules.
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Affiliation(s)
- C Santhosh
- Department of Physics, Banaras Hindu University, Varanasi, India
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Santhosh C, Mishra P. Electric field mapping and structure-activity relationships for some neurotransmitters: serotonin congeners. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0166-1280(94)80205-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Santhosh C, Mishra PC. Electronic spectra of adenine and guanine: Assignments and effects of solution environment. J CHEM SCI 1992. [DOI: 10.1007/bf02839111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Santhosh C, Mishra P. Electronic spectra of 2-aminopurine and 2,6-diaminopurine: phototautomerism and fluorescence reabsorption. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0584-8539(91)80006-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Santhosh C, Mishra PC. Spectroscopic evidence for structural oscillations in DNA caused by oxygen. Indian J Biochem Biophys 1990; 27:209-12. [PMID: 2286384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
It has been shown that interaction of dissolved oxygen with DNA in an aqueous solution causes oscillations in the DNA structure and leads to the formation of a loose DNA-oxygen complex. These results have been compared with those obtained with solution of DNA in high salt concentration.
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Affiliation(s)
- C Santhosh
- Department of Physics, Banaras Hindu University, Varanasi, India
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Santhosh C, Mishra P. Electronic spectra of adenine: interaction with dissolved oxygen in solution, oscillation and intensification of n-π* transition. J Mol Struct 1990. [DOI: 10.1016/0022-2860(90)80097-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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