1
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Ashraf A, Ahmad M, Mariadasse R, Khan MA, Noor S, Islam A, Hassan MI. Integrated spectroscopic and MD simulation approach to decipher the effect of pH on the structure function of Staphylococcus aureus thymidine kinase. J Biomol Struct Dyn 2023:1-12. [PMID: 38100604 DOI: 10.1080/07391102.2023.2293270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023]
Abstract
Staphylococcus aureus is a major human pathogen responsible for a variety of clinical infections, becoming increasingly resistant to antibiotics. To address this challenge, there is a need to identify new cellular targets and innovative approaches to expand treatment options. One such target is thymidine kinase (TK), a crucial enzyme in the pyrimidine salvage pathway, which plays a key role in the phosphorylation of thymidine, an essential component in DNA synthesis and repair. In this study, we have successfully cloned, expressed, and purified the TK protein. A comprehensive investigation into how different pH levels affect the structure and functional activity of TK, using a combination of spectroscopy, classical molecular dynamics simulations, and enzyme activity assays was conducted. Our study revealed that variation in pH disrupts secondary and tertiary structures of TK with noticeable aggregate formation at pH 5.0. Enzyme activity studies demonstrated that TK exhibited its maximum kinase activity within the physiological pH range. These findings strongly suggest a connection between structural changes and enzymatic activity, which was further supported by the agreement between the spectroscopic features we measured and the results of our MD simulations. Our study provides a deeper insight into the structural features of TK, which could potentially be harnessed for the development of therapeutic strategies aimed at combatting infectious diseases. Conformational dynamics plays an essential role in the design and development of effective inhibitors. Considering the effects of pH on the conformational dynamics of TK, our findings may be implicated in the development of potent and selective inhibitors.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Anam Ashraf
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | | | - Richard Mariadasse
- Structural Biology and Bio-Computing Laboratory, Department of Bioinformatics, Alagappa University, Karaikudi, India
| | - Monis Ali Khan
- Department of Biochemistry, School of Chemical and Life Sciences, New Delhi, India
| | - Saba Noor
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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2
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Mechanistic insights into the urea-induced denaturation of human sphingosine kinase 1. Int J Biol Macromol 2020; 161:1496-1505. [PMID: 32771517 DOI: 10.1016/j.ijbiomac.2020.07.280] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/04/2020] [Accepted: 07/18/2020] [Indexed: 12/17/2022]
Abstract
Sphingosine kinase 1 (SphK1) plays a significant role in various cellular processes, including cell proliferation, apoptosis, and angiogenesis. SphK1 is considered as an attractive target for drug development owing to its connection with several diseases, including cancer. In the current work, the urea-induced unfolding of SphK1 was performed at pH 8.0 and 25 °C using CD and fluorescence spectroscopy. SphK1 follows a biphasic unfolding transition (N ⇌ I ⇌ D) with an intermediate (I) state populated around 4.0 M urea concentration. The circular dichroism ([θ]222) and fluorescence emission spectra (λmax) of SphK1 with increasing concentrations of urea were analyzed to calculate Gibbs free energy (ΔG0) for both the transitions (N ⇌ I and I ⇌ D). A significant overlap of both the transitions obtained by two spectroscopic properties ([θ]222 and λmax) was observed, indicating that both N ⇌ I and I ⇌ D transition follow two-step equilibrium unfolding pattern. Also, we performed 100 ns molecular dynamics (MD) simulations to get atomistic insights into the structural changes in SphK1 with increasing urea concentrations. Our results showed a consistent pattern of the SphK1 unfolding with increasing urea concentrations. Together, spectroscopic and MD simulation findings provide deep insights into the unfolding mechanism and conformational features of SphK1.
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3
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Alamry KA, Srivastava S, Shahbaaz M, Khan P, Gupta P, Syed SB, Azum N, Asiri AM, Islam A, Ahmad F, Hassan MI. Unravelling the unfolding pathway of human Fas-activated serine/threonine kinase induced by urea. J Biomol Struct Dyn 2020; 39:5516-5525. [PMID: 32662329 DOI: 10.1080/07391102.2020.1790423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Fas-activated serine/threonine kinase (FASTK) is a mitochondria-associated nuclear protein that inhibits Fas- and UV-induced apoptosis. This protein is generally activated during Fas-mediated apoptosis by phosphorylating a nuclear RNA-binding protein T-cell intracellular antigen-1 and thus considered as a modulator of apoptosis. In the present study, we have examined the equilibrium unfolding and conformational stability of the kinase domain of FASTK (FASTK353-444). The kinase domain of FASTK353-444 was cloned, expressed, and purified. The folding ↔ unfolding transitions of urea-induced denaturation was monitored with the help of circular dichroism, intrinsic fluorescence, and UV absorption spectroscopies. Analysis of transition curves obtained from different probes revealed a coincidence of denaturation curves, suggesting that folding/unfolding of FASTK follows a two-state process with the midpoint (Cm) value at 3.50 ± 0.1 M. Urea-induced denaturation curves were further analyzed to estimate change in the Gibbs free energy in the absence of urea (ΔGD0) associated with the equilibrium of denaturation. To get atomistic insights into the urea-induced denaturation of FASTK, we performed an all-atom molecular dynamics simulation for 100 ns. A close agreement was noticed between experimental and computational studies. This study will help to understand the unfolding mechanism and structural stability of the kinase domain of FASTK.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Khalid A Alamry
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Saurabha Srivastava
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Mohd Shahbaaz
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Bellville, Cape Town, South Africa.,Laboratory of Computational Modeling of Drugs, South Ural State University, Chelyabinsk, Russia
| | - Parvez Khan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Preeti Gupta
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Sunayana Begum Syed
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Naved Azum
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Abdullah M Asiri
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.,Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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4
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Gupta P, Khan FI, Roy S, Anwar S, Dahiya R, Alajmi MF, Hussain A, Rehman MT, Lai D, Hassan MI. Functional implications of pH-induced conformational changes in the Sphingosine kinase 1. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 225:117453. [PMID: 31446356 DOI: 10.1016/j.saa.2019.117453] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/21/2019] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
Sphingosine kinase 1 (SphK1) catalyzes the conversion of sphingosine to sphingosine-1-phosphate that acts as a bioactive signalling molecule, and regulates various cellular processes including lymphocyte trafficking, angiogenesis and response to apoptotic stimuli. Abnormal expression of SphK1 has been observed in a wide range of cancers highlighting their role in tumour growth and metastasis. This enzyme also plays a critical role in metabolic and inflammatory diseases, including pulmonary fibrosis, diabetic neuropathy and Alzheimer's disease. In the present study, we have investigated the structural and conformational changes in SphK1 at varying pH using various spectroscopic techniques. Consistent results were observed with the function of SphK1 at corresponding pH values. SphK1 maintains its secondary and tertiary structure in the pH range of 7.5-10.0. However, protein aggregation was observed in the acidic pH range (4.0-6.5). At pH 2.0, the SphK1 exists in the molten-globule state. Kinase assay also shows that SphK1 activity was optimal in the pH range of 7.5-8.5. To complement in vitro results, we have performed 100 ns molecular dynamics simulation to examine the effect of pH on the structural stability of SphK1 at molecular level. SphK1 maintains its native conformation in the alkaline pH range with some residual fluctuations detected at acidic pH. A considerable correlation was noticed between spectroscopic, enzymatic activity and MD simulation studies. pH dependent structural changes can be further implicated to understand its association with disease condition, and cellular homeostasis with respect to protein function under variable pH conditions.
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Affiliation(s)
- Preeti Gupta
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Faez Iqbal Khan
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Sonam Roy
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Saleha Anwar
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Rashmi Dahiya
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Mohammed F Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Md Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Dakun Lai
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India.
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5
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Gupta P, Khan FI, Ambreen D, Lai D, Alajmi MF, Hussain A, Islam A, Ahmad F, Hassan MI. Investigation of guanidinium chloride-induced unfolding pathway of sphingosine kinase 1. Int J Biol Macromol 2020; 147:177-186. [PMID: 31917989 DOI: 10.1016/j.ijbiomac.2020.01.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/03/2020] [Accepted: 01/04/2020] [Indexed: 01/11/2023]
Abstract
Sphingosine kinase 1 (SphK1) is a lipid kinase which plays vital role in the regulation of varieties of biological processes including, cell growth, apoptosis and mitogenesis. In the present study, we investigated the guanidinium chloride (GdmCl)-induced denaturation of SphK1 at pH 8.0 and 25 °C using two different spectroscopic probes, i.e., mean residue ellipticity at 222 nm ([θ]222) and fluorescence emission maxima (λmax). A significant overlap between the transition curves obtained from both the spectral properties indicate that GdmCl-induced unfolding of SphK1 follows two-state process i.e., Native (N) ⇌ Denatured (D) state. Interestingly, a visible protein aggregation was observed at low concentrations of GdmCl ([GdmCl] ≤ 1.5 M). The analysis of transition curves was done to estimate the thermodynamic parameters associated with the stability of SphK1. To complement our experimental findings, 100 ns molecular dynamics (MD) simulations were performed. Spectroscopic studies together with MD simulations provided mechanistic insights of unfolding pathway of SphK1 along with its stability parameters.
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Affiliation(s)
- Preeti Gupta
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Faez Iqbal Khan
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Dilkash Ambreen
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Dakun Lai
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Mohamed F Alajmi
- Department of Pharmacognosy College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Afzal Hussain
- Department of Pharmacognosy College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India.
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6
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Trigui I, Zarai Z, Chevance S, Cheikh-Rouhou S, Attia H, Ayadi M. Physicochemical properties, antioxidant activity and in vitro gastrointestinal digestion of purified proteins from black cumin seeds. Int J Biol Macromol 2019; 126:454-465. [DOI: 10.1016/j.ijbiomac.2018.12.198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/13/2018] [Accepted: 12/21/2018] [Indexed: 12/29/2022]
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7
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Khan SH, Prakash A, Pandey P, Lynn AM, Islam A, Hassan MI, Ahmad F. Protein folding: Molecular dynamics simulations and in vitro studies for probing mechanism of urea- and guanidinium chloride-induced unfolding of horse cytochrome-c. Int J Biol Macromol 2019; 122:695-704. [DOI: 10.1016/j.ijbiomac.2018.10.186] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/27/2018] [Accepted: 10/27/2018] [Indexed: 11/26/2022]
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8
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Purification, modeling and structural insights of calmodulin-binding receptor like cytoplasmic kinase 2 from Oroxylum Indicum. Int J Biol Macromol 2019; 123:704-712. [DOI: 10.1016/j.ijbiomac.2018.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/02/2018] [Accepted: 11/02/2018] [Indexed: 12/25/2022]
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9
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Syed SB, Khan FI, Khan SH, Srivastava S, Hasan GM, Lobb KA, Islam A, Ahmad F, Hassan MI. Mechanistic insights into the urea-induced denaturation of kinase domain of human integrin linked kinase. Int J Biol Macromol 2018; 111:208-218. [DOI: 10.1016/j.ijbiomac.2017.12.164] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/29/2017] [Accepted: 12/30/2017] [Indexed: 01/01/2023]
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10
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Shahbaaz M, Amir M, Rahman S, Mustafa Hasan G, Dohare R, Bisetty K, Ahmad F, Kim J, Hassan MI. Structural insights into Rab21 GTPase activation mechanism by molecular dynamics simulations. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1357813] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Mohd. Shahbaaz
- Department of Chemistry, Durban University of Technology, Durban, South Africa
| | - Mohd. Amir
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Safikur Rahman
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, South Korea
| | - Gulam Mustafa Hasan
- Department of Biochemistry, College of Medicine, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Ravins Dohare
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Krishna Bisetty
- Department of Chemistry, Durban University of Technology, Durban, South Africa
| | - Faizan Ahmad
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Jihoe Kim
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, South Korea
| | - Md. Imtaiyaz Hassan
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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11
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Prakash A, Dixit G, Meena NK, Singh R, Vishwakarma P, Mishra S, Lynn AM. Elucidation of stable intermediates in urea-induced unfolding pathway of human carbonic anhydrase IX. J Biomol Struct Dyn 2017; 36:2391-2406. [DOI: 10.1080/07391102.2017.1355847] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Amresh Prakash
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Gunjan Dixit
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Naveen Kumar Meena
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ruhar Singh
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Poonam Vishwakarma
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Smriti Mishra
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Andrew M. Lynn
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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12
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Shamsi TN, Athar T, Parveen R, Fatima S. A review on protein misfolding, aggregation and strategies to prevent related ailments. Int J Biol Macromol 2017; 105:993-1000. [PMID: 28743576 DOI: 10.1016/j.ijbiomac.2017.07.116] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 07/13/2017] [Accepted: 07/18/2017] [Indexed: 01/28/2023]
Abstract
This review aims to highlight the fundamental mechanism of protein misfolding leading to protein aggregation and associated diseases. It also aims to anticipate novel therapeutic strategies with which to prevent or treat these highly debilitating conditions linked to these pathologies. The failure of a protein to correctly fold de novo or to remain correctly folded can have profound consequences on a living system especially when the cellular quality control processes fail to eliminate the rogue proteins. The core cause of over 20 different human diseases which have now been designated as 'conformational diseases' including neurodegenerative diseases such as Alzheimer's disease (AD), Huntington's disease (HD) and Parkinson's disease (PD) etc. A comprehensive study on protein misfolding, aggregation, and the outcomes of the effects of cytotoxic aggregates will lead to understand the aggregation-mediated cell toxicity and serves as a foundation for future research in development of promising therapies and drugs. This review has also shed light on the mechanism of protein misfolding which leads to its aggregation and hence the neurodegeneration. From these considerations, one could also envisage the possibility that protein aggregation may be exploited by nature to perform specific physiological functions in differing biological contexts.
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Affiliation(s)
- Tooba Naz Shamsi
- Department of Biotechnology, Jamia Millia Islamia, New Delhi 110025, India.
| | - Teeba Athar
- Department of Biotechnology, Jamia Millia Islamia, New Delhi 110025, India.
| | - Romana Parveen
- Department of Biotechnology, Jamia Millia Islamia, New Delhi 110025, India.
| | - Sadaf Fatima
- Department of Biotechnology, Jamia Millia Islamia, New Delhi 110025, India.
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13
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Wahiduzzaman, Dar MA, Haque MA, Idrees D, Hassan MI, Islam A, Ahmad F. Characterization of folding intermediates during urea-induced denaturation of human carbonic anhydrase II. Int J Biol Macromol 2017; 95:881-887. [DOI: 10.1016/j.ijbiomac.2016.10.073] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 10/07/2016] [Accepted: 10/22/2016] [Indexed: 11/25/2022]
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14
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Kumar V, Sami N, Kashav T, Islam A, Ahmad F, Hassan MI. Protein aggregation and neurodegenerative diseases: From theory to therapy. Eur J Med Chem 2016; 124:1105-1120. [DOI: 10.1016/j.ejmech.2016.07.054] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 12/23/2022]
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15
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Idrees D, Prakash A, Haque MA, Islam A, Hassan MI, Ahmad F. GdnHCl-induced unfolding intermediate in the mitochondrial carbonic anhydrase VA. Int J Biol Macromol 2016; 91:1151-60. [DOI: 10.1016/j.ijbiomac.2016.06.080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/24/2016] [Accepted: 06/26/2016] [Indexed: 10/21/2022]
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16
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Khan FI, Bisetty K, Singh S, Permaul K, Hassan MI. Chitinase from Thermomyces lanuginosus SSBP and its biotechnological applications. Extremophiles 2016; 19:1055-66. [PMID: 26462798 DOI: 10.1007/s00792-015-0792-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/03/2015] [Indexed: 12/30/2022]
Abstract
Chitinases are ubiquitous class of extracellular enzymes, which have gained attention in the past few years due to their wide biotechnological applications. The effectiveness of conventional insecticides is increasingly compromised by the occurrence of resistance; thus, chitinase offers a potential alternative to the use of chemical fungicides. The thermostable enzymes from thermophilic microorganisms have numerous industrial, medical, environmental and biotechnological applications due to their high stability for temperature and pH. Thermomyces lanuginosus produced a large number of chitinases, of which chitinase I and II are successfully cloned and purified recently. Molecular dynamic simulations revealed that the stability of these enzymes are maintained even at higher temperature. In this review article we have focused on chitinases from different sources, mainly fungal chitinase of T. lanuginosus and its industrial application.
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17
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Khan P, Shandilya A, Jayaram B, Islam A, Ahmad F, Hassan MI. Effect of pH on the stability of hemochromatosis factor E: a combined spectroscopic and molecular dynamics simulation-based study. J Biomol Struct Dyn 2016; 35:1582-1598. [PMID: 27174123 DOI: 10.1080/07391102.2016.1189359] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hereditary hemochromatosis is an iron overburden condition, which is mainly governed by hereditary hemochromatosis factor E (HFE), a member of major histocompatibility complex class I. To understand the effect of pH on the structure and stability of HFE, we have cloned, expressed, and purified the HFE in the bacterial system and performed circular dichroism, fluorescence, and absorbance measurements at a wide pH range (pH 3.0-11.0). We found that HFE remains stable in the pH range 7.5-11.0 and gets completely acid denatured at low pH values. In this work, we also analyzed the contribution of salt bridges to the stability of HFE. We further performed molecular dynamics simulations for 80 ns at different pH values. An excellent agreement was observed between results from biophysical and MD simulation studies. At lower pH, HFE undergoes denaturation and may be driven toward a degradation pathway, such as ubiquitination. Hence, HFE is not available to bind again with transferrin receptor1 to negatively regulate iron homeostasis. Further we postulated that, might be low pH of cancerous cells helps them to meet their high iron requirement.
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Affiliation(s)
- Parvez Khan
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , New Delhi 110025 , India
| | - Ashutosh Shandilya
- b Department of Chemistry , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - B Jayaram
- b Department of Chemistry , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Asimul Islam
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , New Delhi 110025 , India
| | - Faizan Ahmad
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , New Delhi 110025 , India
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18
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Zaidi S, Haque MA, Ubaid-ullah S, Prakash A, Hassan MI, Islam A, Batra JK, Ahmad F. Denatured states of yeast cytochrome c induced by heat and guanidinium chloride are structurally and thermodynamically different. J Biomol Struct Dyn 2016; 35:1420-1435. [DOI: 10.1080/07391102.2016.1185039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sobia Zaidi
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Md. Anzarul Haque
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Shah Ubaid-ullah
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
- Department of Biotechnology, School of Life Sciences, Central University of Kashmir (CUK), Sonwar Campus, Srinagar 190004, India
| | - Amresh Prakash
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Janendra K. Batra
- Immunochemistry Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
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19
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Purification and characterization of RGA2, a Rho2 GTPase-activating protein from Tinospora cordifolia. 3 Biotech 2016; 6:85. [PMID: 28330155 PMCID: PMC4773375 DOI: 10.1007/s13205-016-0400-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 01/22/2016] [Indexed: 01/23/2023] Open
Abstract
Rho GTPases activating protein 2 (RGA2) is primarily involved in the modulation of numerous morphological events in eukaryotes. It protects plants by triggering the defense system which restricts the pathogen growth. This is the first report on the isolation, purification and characterization of RGA2 from the stems of Tinospora cordifolia, a medicinal plant. The RGA2 was purified using simple two-step process using DEAE-Hi-Trap FF and Superdex 200 chromatography columns, with a high yield. The purity of RGA2 was confirmed by SDS-PAGE and identified by MALDI-TOF/MS. The purified protein was further characterized for its secondary structural elements using the far-UV circular dichroism measurements. Our purification procedure is simple two-step process with high yield which can be further used to produce RGA2 for structural and functional studies.
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Prakash A, Idrees D, Haque MA, Islam A, Ahmad F, Hassan MI. GdmCl-induced unfolding studies of human carbonic anhydrase IX: a combined spectroscopic and MD simulation approach. J Biomol Struct Dyn 2016; 35:1295-1306. [PMID: 27092977 DOI: 10.1080/07391102.2016.1179596] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Carbonic anhydrase IX (CAIX) is a transmembrane glycoprotein, associated with tumor, acidification which leads to the cancer, and is considered as a potential biomarker for hypoxia-induced cancers. The overexpression of CAIX is linked with hypoxia condition which is mediated by the transcription of hypoxia-induced factor (HIF-1). To understand the biophysical properties of CAIX, we have carried out a reversible isothermal denaturation of CAIX-induced by GdmCl at pH 8.0 and 25°C. Three different spectroscopic probes, the far-UV CD at 222 nm ([θ]222), Trp fluorescence emission at 342 nm (F342) and difference molar absorption coefficient at 287 nm (Δε287) were used to estimate stability parameters, [Formula: see text] (Gibbs free energy change in the absence of GdmCl; Cm (midpoint of the denaturation curve), i.e. molar GdmCl concentration ([GdmCl]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[GdmCl])). GdmCl induces a reversible denaturation of CAIX. Coincidence of the normalized transition curves of all optical properties suggests that unfolding/refolding of CAIX is a two-state process. We further performed molecular dynamics simulation of CAIX for 40 ns to see the dynamics of protein structure in different GdmCl concentrations. An excellent agreement was observed between in silico and in vitro studies.
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Affiliation(s)
- Amresh Prakash
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Danish Idrees
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Anzarul Haque
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Asimul Islam
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
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Anwer K, Rahman S, Sonani RR, Khan FI, Islam A, Madamwar D, Ahmad F, Hassan MI. Probing pH sensitivity of αC-phycoerythrin and its natural truncant: A comparative study. Int J Biol Macromol 2016; 86:18-27. [DOI: 10.1016/j.ijbiomac.2016.01.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/09/2016] [Accepted: 01/13/2016] [Indexed: 12/13/2022]
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Idrees D, Shahbaaz M, Bisetty K, Islam A, Ahmad F, Hassan MI. Effect of pH on structure, function, and stability of mitochondrial carbonic anhydrase VA. J Biomol Struct Dyn 2016; 35:449-461. [PMID: 26828699 DOI: 10.1080/07391102.2016.1149097] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Mitochondrial carbonic anhydrase VA (CAVA) catalyzes the hydration of carbon dioxide to produce proton and bicarbonate which is primarily expressed in the mitochondrial matrix of liver, and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis, and neuronal transmission. To understand the effect of pH on the structure, function, and stability of CAVA, we employed spectroscopic techniques such as circular dichroism, fluorescence, and absorbance measurements in wide range of pH (from pH 2.0 to pH 11.5). CAVA showed an aggregation at acidic pH range from pH 2.0 to pH 5.0. However, it remains stable and maintains its secondary structure in the pH range, pH 7.0-pH 11.5. Furthermore, this enzyme has an appreciable activity at more than pH 7.0 (7.0 < pH ≤ 11.5) with maximum activity at pH 9.0. The maximal values of kcat and kcat/Km at pH 9.0 are 3.7 × 106 s-1 and 5.5 × 107 M-1 s-1, respectively. However, this enzyme loses its activity in the acidic pH range. We further performed 20-ns molecular dynamics simulation of CAVA to see the dynamics at different pH values. An excellent agreement was observed between in silico and in vitro studies. This study provides an insight into the activity of CAVA in the pH range of subcellular environment.
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Affiliation(s)
- Danish Idrees
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India
| | - Mohd Shahbaaz
- b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa
| | - Krishna Bisetty
- b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa
| | - Asimul Islam
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India
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Naz H, Shahbaaz M, Haque MA, Bisetty K, Islam A, Ahmad F, Hassan MI. Urea-induced denaturation of human calcium/calmodulin-dependent protein kinase IV: a combined spectroscopic and MD simulation studies. J Biomol Struct Dyn 2016; 35:463-475. [PMID: 26835540 DOI: 10.1080/07391102.2016.1150203] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Calcium/calmodulin-dependent protein kinase IV (CaMKIV) is a multifunctional enzyme which belongs to the Ser/Thr kinase family. CaMKIV plays important role in varieties of biological processes such as gene expression regulation, memory consolidation, bone growth, T-cell maturation, sperm motility, regulation of microtubule dynamics, cell-cycle progression, and apoptosis. To measure stability parameters, urea-induced denaturation of CaMKIV was carried out at pH 7.4 and 25°C, using three different probes, namely far-UV CD, near-UV absorption, and tryptophan fluorescence. A coincidence of normalized denaturation curves of these optical properties suggests that urea-induced denaturation is a two-state process. Analysis of these denaturation curves gave values of 4.20 ± 0.12 kcal mol-1, 2.95 ± 0.15 M, and 1.42 ± 0.06 kcal mol-1 M-1 for [Formula: see text] (Gibbs free energy change (ΔGD) in the absence of urea), Cm (molar urea concentration ([urea]) at the midpoint of the denaturation curve), and m (=∂ΔGD/∂[urea]), respectively. All these experimental observations have been fully supported by 30 ns molecular dynamics simulation studies.
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Affiliation(s)
- Huma Naz
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Mohd Shahbaaz
- b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa
| | - Md Anzarul Haque
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Krishna Bisetty
- b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa
| | - Asimul Islam
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
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Idrees D, Prakash A, Haque MA, Islam A, Ahmad F, Hassan MI. Spectroscopic and MD simulation studies on unfolding processes of mitochondrial carbonic anhydrase VA induced by urea. J Biomol Struct Dyn 2016; 34:1987-97. [PMID: 26421381 DOI: 10.1080/07391102.2015.1100552] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Carbonic anhydrase VA (CAVA) is primarily expressed in the mitochondria and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis and neuronal transmission. To understand the biophysical properties of CAVA, we carried out a reversible urea-induced isothermal denaturation at pH 7.0 and 25°C. Spectroscopic probes, [θ]222 (mean residue ellipticity at 222 nm), F344 (Trp-fluorescence emission intensity at 344 nm) and Δε280 (difference absorption at 280 nm) were used to monitor the effect of urea on the structure and stability of CAVA. The urea-induced reversible denaturation curves were used to estimate [Formula: see text], Gibbs free energy in the absence of urea; Cm, the mid-point of the denaturation curve, i.e. molar urea concentration ([urea]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[urea]). Coincidence of normalized transition curves of all optical properties suggests that unfolding/refolding of CAVA is a two-state process. We further performed 40 ns molecular dynamics simulation of CAVA to see the dynamics at different urea concentrations. An excellent agreement was observed between in silico and in vitro studies.
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Affiliation(s)
- Danish Idrees
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Amresh Prakash
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Anzarul Haque
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Asimul Islam
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
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Kumari S, Idrees D, Mishra CB, Prakash A, Wahiduzzaman, Ahmad F, Hassan MI, Tiwari M. Design and synthesis of a novel class of carbonic anhydrase-IX inhibitor 1-(3-(phenyl/4-fluorophenyl)-7-imino-3H-[1,2,3]triazolo[4,5d]pyrimidin 6(7H)yl)urea. J Mol Graph Model 2016; 64:101-109. [PMID: 26826799 DOI: 10.1016/j.jmgm.2016.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/11/2016] [Accepted: 01/16/2016] [Indexed: 02/07/2023]
Abstract
Carbonic anhydrase IX (CAIX) is a promising target in cancer therapy especially in the case of hypoxia-induced tumors. The selective inhibition of CA isozymes is a challenging task in drug design and discovery process. Here, we performed fluorescence-binding studies and inhibition assay combined with molecular docking and molecular dynamics (MD) simulation analyses to determine the binding affinity of two synthesized triazolo-pyrimidine urea derived (TPUI and TPUII) compounds with CAIX and CAII. Fluorescence binding results are showing that molecule TPUI has an excellent binding-affinity for CAIX (kD=0.048μM). The TPUII also exhibits an appreciable binding affinity (kD=7.52μM) for CAIX. TPUI selectively inhibits CAIX as compared to TPUII in the 4-NPA assay. Docking studies show that TPUI is spatially well-fitted in the active site cavity of CAIX, and is involve in H-bond interactions with His94, His96, His119, Thr199 and Thr200. MD simulation studies revealed that TPUI efficiently binds to CAIX and essential active site residual interaction is consistent during the entire simulation of 40ns. These studies suggest that TPUI appeared as novel class of CAIX inhibitor, and may be used as a lead molecule for the development of potent and selective CAIX inhibitor for the hypoxia-induced cancer therapy.
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Affiliation(s)
- Shikha Kumari
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, New Delhi 110007, India
| | - Danish Idrees
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Chandra Bhushan Mishra
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, New Delhi 110007, India
| | - Amresh Prakash
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Wahiduzzaman
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
| | - Manisha Tiwari
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, New Delhi 110007, India.
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Amir M, Wahiduzzaman, Dar MA, Haque MA, Islam A, Ahmad F, Hassan MI. Purification and characterization of Ras related protein, Rab5a from Tinospora cordifolia. Int J Biol Macromol 2016; 82:471-9. [DOI: 10.1016/j.ijbiomac.2015.10.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 11/27/2022]
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Khan S, Shahbaaz M, Bisetty K, Ahmad F, Hassan MI. Classification and Functional Analyses of Putative Conserved Proteins from Chlamydophila pneumoniae CWL029. Interdiscip Sci 2015; 9:96-106. [PMID: 26649559 DOI: 10.1007/s12539-015-0134-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/19/2015] [Accepted: 11/24/2015] [Indexed: 12/01/2022]
Abstract
Chlamydophila pneumoniae, a Gram-negative bacterium belongs to the family Chlamydiaceae, is known to cause community-acquired pneumonia and bronchitis. There is a need for genomic analyses of C. pneumoniae as its chronic infections result in reactive airway disease, lung cancer and asthma. Recent advancement in the sequencing techniques led to the generation of large genomic data. In order to utilize these data, sequence-based function predictions were used for annotating the uncharacterized genes. The genome of C. pneumoniae encodes 1052 proteins, which include a group of 366 functionally uncharacterized proteins, known as "hypothetical proteins" (HPs). Functions of these HPs were predicted by utilizing an integrated approach that combines varieties of bioinformatics tools. The functions of 142 proteins were successfully predicted and categorized into different classes of enzymes, transport proteins, binding proteins and virulence factors. Among these functionally annotated HPs, we were able to identify 12 virulent HPs. Furthermore, the HP with the highest virulence score was subjected to molecular dynamics (MD) simulations to better understand their dynamical behavior in explicit water conditions. These analyses could be utilized for an in-depth understanding of virulence mechanism. The functional knowledge of these proteins could be useful in drug design and discovery process of infections caused by C. pneumoniae.
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Affiliation(s)
- Shama Khan
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Mohd Shahbaaz
- Department of Chemistry, Durban University of Technology, Durban, 4000, South Africa
| | - Krishna Bisetty
- Department of Chemistry, Durban University of Technology, Durban, 4000, South Africa
| | - Faizan Ahmad
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Md Imtaiyaz Hassan
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India.
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Purification and characterization of oligonucleotide binding (OB)-fold protein from medicinal plant Tinospora cordifolia. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 1008:38-44. [PMID: 26613539 DOI: 10.1016/j.jchromb.2015.11.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/09/2015] [Accepted: 11/12/2015] [Indexed: 12/11/2022]
Abstract
The oligonucleotide binding fold (OB-fold) is a small structural motif present in many proteins. It is originally named for its oligonucleotide or oligosaccharide binding properties. These proteins have been identified as essential for replication, recombination and repair of DNA. We have successfully purified a protein contains OB-fold from the stem of Tinospora cordifolia, a medicinal plants of north India. Stems were crushed and centrifuged, and fraction obtained at 60% ammonium sulphate was extensively dialyzed and applied to the weak anion exchange chromatography on Hi-Trap DEAE-FF in 50mM Tris-HCl buffer at pH 8.0. Eluted fractions were concentrated and applied to gel filtration column to get pure protein. We observed a single band of 20-kDa on SDS-PAGE. Finally, the protein was identified as OB-fold by MALDI-TOF. The purified OB-fold protein was characterized for its secondary structural elements using circular dichroism (CD) in the far-UV region. Generally the OB-fold has a characteristic feature as five-stranded beta-sheet coiled to form a closed beta- barrel. To estimate its chemical stability, guanidinium chloride-induced denaturation curve was followed by observing changes in the far-UV CD as a function of the denaturant concentration. Analysis of this denaturation curve gave values of 8.90±0.25kcalmol(-1) and 3.78±0.18M for ΔGD° (Gibbs free energy change at 25°C) and Cm (midpoint of denaturation), respectively. To determine heat stability parameters of OB-fold protein, differential scanning calorimetry was performed. Calorimetric values of ΔGD°, Tm (midpoint of denaturation), ΔHm (enthalpy change at Tm), and ΔCp (constant-pressure heat capacity change) are 9.05±0.27kcalmol(-1), 85.2±0,3°C, 105±4kcalmol(-1) and 1.6±0.08kcalmol(-1)K(-1). This is the first report on the isolation, purification and characterization of OB-fold protein from a medicinal plant T. cordifolia.
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Naz F, Singh P, Islam A, Ahmad F, Imtaiyaz Hassan M. Human microtubule affinity-regulating kinase 4 is stable at extremes of pH. J Biomol Struct Dyn 2015. [PMID: 26208600 DOI: 10.1080/07391102.2015.1074942] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
MAP/microtubule affinity-regulating kinase 4 (MARK4) is a member of adenosine monophosphate-activated protein kinases, directly associated with cancer and neurodegenerative diseases. Here, we have cloned, expressed, and purified two variants of MARK4 [the kinase domain (MARK4-F2), and kinase domain along with 59 N-terminal residues (MARK4-F1)] and compared their stability at varying pH range. Structural and functional changes were observed by incubating both forms of MARK4 in buffers of different pH. We measured the secondary structure of MARK4 using circular dichroism and tertiary structure by measuring intrinsic fluorescence and absorbance properties along with the size of proteins by dynamic light scattering. We observed that at extremes of pH (below pH 3.5 and above pH 9.0), MARK4 is quite stable. However, a remarkable aggregate formation was observed at intermediate pH (between pH 3.5 and 9.0). To further validate this result, we have modeled both forms of MARK4 and performed molecular dynamics simulation for 15 ns. The spectroscopic observations are in excellent agreement with the findings of molecular dynamics simulation. We also performed ATPase activity at varying pH and found a significant correlation of structure of MARK4 with its enzyme activity. It is interesting to note that both forms of MARK4 are showing a similar pattern of structure changes with reference to pH.
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Affiliation(s)
- Farha Naz
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Parvesh Singh
- b School of Chemistry and Physics , University of Kwa-Zulu Natal , Chiltern Hill, Durban 4000 , South Africa
| | - Asimul Islam
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Md Imtaiyaz Hassan
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
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Naiyer A, Hassan MI, Islam A, Sundd M, Ahmad F. Structural characterization of MG and pre-MG states of proteins by MD simulations, NMR, and other techniques. J Biomol Struct Dyn 2015; 33:2267-84. [PMID: 25586676 DOI: 10.1080/07391102.2014.999354] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Almost all proteins fold via a number of partially structured intermediates such as molten globule (MG) and pre-molten globule states. Understanding the structure of these intermediates at atomic level is often a challenge, as these states are observed under extreme conditions of pH, temperature, and chemical denaturants. Furthermore, several other processes such as chemical modification, site-directed mutagenesis (or point mutation), and cleavage of covalent bond of natural proteins often lead to MG like partially unfolded conformation. However, the dynamic nature of proteins in these states makes them unsuitable for most structure determination at atomic level. Intermediate states studied so far have been characterized mostly by circular dichroism, fluorescence, viscosity, dynamic light scattering measurements, dye binding, infrared techniques, molecular dynamics simulations, etc. There is a limited amount of structural data available on these intermediate states by nuclear magnetic resonance (NMR) and hence there is a need to characterize these states at the molecular level. In this review, we present characterization of equilibrium intermediates by biophysical techniques with special reference to NMR.
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Affiliation(s)
- Abdullah Naiyer
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi - 110025 , India
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