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Nanda Kumar Y, Jeyakodi G, Gunasekaran K, Jambulingam P. Computational screening and characterization of putative vaccine candidates of Plasmodium vivax. J Biomol Struct Dyn 2015; 34:1736-50. [PMID: 26338678 DOI: 10.1080/07391102.2015.1090344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Plasmodium vivax is the most prevalent species of malaria affecting millions of people annually worldwide and demands effective interventions to develop a successful vaccine. In this milieu, we have dedicated noteworthy efforts to characterize the proteome of P. vivax to give a lead for the epitope-based vaccine development. Membrane proteins of P. vivax were collected from SWISS PROT database and 10 antigenic proteins were identified among them by in silico analysis using multiple servers. T-cell and B-cell epitopes were identified and their immunity was assessed. Their ability to trigger humoral and cell-mediated responses was determined. Three dimensional models were constructed for the antigenic proteins using Modeller, Phyre2, and Modloop tools and their quality was validated using PROCHECK and ProSA-web validation servers. Further, the binding affinity and molecular interactions of these antigenic proteins were characterized by performing protein-protein docking against transmission-blocking anti-malaria antibody Fab2A8 (PDB ID: 3S62) using Z-dock module of Discovery Studio 4.0. The presence of potential B & T-cell epitopes, major histocompatibility complex-binding sites, and their efficient interactions with Fab2A8 antibody suggests the use of predicted antigenic proteins for the construction of multi-epitope peptide vaccine against P. vivax.
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Affiliation(s)
- Y Nanda Kumar
- a Biomedical Informatics Centre, Vector Control Research Centre , Indian Council of Medical Research , Pondicherry 605006 , India
| | - G Jeyakodi
- a Biomedical Informatics Centre, Vector Control Research Centre , Indian Council of Medical Research , Pondicherry 605006 , India
| | - K Gunasekaran
- a Biomedical Informatics Centre, Vector Control Research Centre , Indian Council of Medical Research , Pondicherry 605006 , India
| | - P Jambulingam
- a Biomedical Informatics Centre, Vector Control Research Centre , Indian Council of Medical Research , Pondicherry 605006 , India
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Abstract
Protein thermostability has been the focus of growing research interests in the last decades since its understanding and control play important roles in the optimization of a wide series of bioprocesses of academic and industrial importance. The complexity of this issue is rooted in the fact that the mechanisms ensuring thermal resistance are not unique and specific, but rather family- or even protein-dependent. Therefore, and despite the amount of research already accomplished, obtaining fast and precise thermal stability predictions is still a challenge, especially on a large scale. This article deepens the study of protein thermal stability and is focused on the prediction of its best descriptor, the melting temperature Tm. The relations between Tm and a series of factors that are expected to influence the protein stability are analyzed and discussed. Different Tm-prediction methods that utilize these factors, sometimes with additional information about homologous proteins, are introduced, and their individual performances are evaluated. The best methods are based on temperature-dependent statistical potentials, on the environmental temperature of the host organism, on the fraction of charged residues, and on the number of residues. They are combined to build an improved prediction method with significantly increased score. The root mean square deviation between the computed and experimental Tm-values for 45 proteins of known structure from 11 families is about 7°C in cross-validation and decreases to 5°C when 10% outliers are removed. The associated linear correlation coefficients are equal to .91 and .95, respectively.
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Affiliation(s)
- Fabrizio Pucci
- a Department of BioModeling, BioInformatics & BioProcesses , Université Libre de Bruxelles , Roosevelt Ave. 50, 1050 Brussels , Belgium
| | - Marianne Rooman
- a Department of BioModeling, BioInformatics & BioProcesses , Université Libre de Bruxelles , Roosevelt Ave. 50, 1050 Brussels , Belgium
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Abhinand PA, Shaikh F, Bhakat S, Radadiya A, Bhaskar LVKS, Shah A, Ragunath PK. Insights on the structural perturbations in human MTHFR Ala222Val mutant by protein modeling and molecular dynamics. J Biomol Struct Dyn 2015; 34:892-905. [PMID: 26273990 DOI: 10.1080/07391102.2015.1057866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) protein catalyzes the only biochemical reaction which produces methyltetrahydrofolate, the active form of folic acid essential for several molecular functions. The Ala222Val polymorphism of human MTHFR encodes a thermolabile protein associated with increased risk of neural tube defects and cardiovascular disease. Experimental studies have shown that the mutation does not affect the kinetic properties of MTHFR, but inactivates the protein by increasing flavin adenine dinucleotide (FAD) loss. The lack of completely solved crystal structure of MTHFR is an impediment in understanding the structural perturbations caused by the Ala222Val mutation; computational modeling provides a suitable alternative. The three-dimensional structure of human MTHFR protein was obtained through homology modeling, by taking the MTHFR structures from Escherichia coli and Thermus thermophilus as templates. Subsequently, the modeled structure was docked with FAD using Glide, which revealed a very good binding affinity, authenticated by a Glide XP score of -10.3983 (kcal mol(-1)). The MTHFR was mutated by changing Alanine 222 to Valine. The wild-type MTHFR-FAD complex and the Ala222Val mutant MTHFR-FAD complex were subjected to molecular dynamics simulation over 50 ns period. The average difference in backbone root mean square deviation (RMSD) between wild and mutant variant was found to be ~.11 Å. The greater degree of fluctuations in the mutant protein translates to increased conformational stability as a result of mutation. The FAD-binding ability of the mutant MTHFR was also found to be significantly lowered as a result of decreased protein grip caused by increased conformational flexibility. The study provides insights into the Ala222Val mutation of human MTHFR that induces major conformational changes in the tertiary structure, causing a significant reduction in the FAD-binding affinity.
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Affiliation(s)
- P A Abhinand
- a Department of Bioinformatics , Sri Ramachandra University , Porur, Chennai 600 116 , India
| | - Faraz Shaikh
- b Center for Excellence, National Facility for Drug Discovery Complex, Department of Chemistry , Saurashtra University , Rajkot , Gujarat , India
| | - Soumendranath Bhakat
- d Division of Biophysical Chemistry , Lund University , P.O. Box 124, SE-22100 Lund , Sweden
| | - Ashish Radadiya
- b Center for Excellence, National Facility for Drug Discovery Complex, Department of Chemistry , Saurashtra University , Rajkot , Gujarat , India
| | - L V K S Bhaskar
- c Department of Biomedical Sciences , Sri Ramachandra University , Porur, Chennai 600 116 , India
| | - Anamik Shah
- b Center for Excellence, National Facility for Drug Discovery Complex, Department of Chemistry , Saurashtra University , Rajkot , Gujarat , India
| | - P K Ragunath
- a Department of Bioinformatics , Sri Ramachandra University , Porur, Chennai 600 116 , India
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Saranya N, Saravanan KM, Michael Gromiha M, Selvaraj S. Analysis of secondary structural and physicochemical changes in protein-protein complexes. J Biomol Struct Dyn 2015; 34:508-16. [PMID: 25990569 DOI: 10.1080/07391102.2015.1050695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Conformation switching in protein-protein complexes is considered important for the molecular recognition process. Overall analysis of 123 protein-protein complexes in a benchmark data-set showed that 6.8% of residues switched over their secondary structure conformation upon complex formation. Amino acid residue-wise preference for conformation change has been analyzed in binding and non-binding site residues separately. In this analysis, residues such as Ser, Leu, Glu, and Lys had higher frequency of secondary structural conformation change. The change of helix to coil and sheet to coil conformation and vice versa has been observed frequently, whereas the conformation change of helix to extended sheet occurred rarely in the studied complexes. Influence of conformation change toward the N and C terminal on either side of the binding site residues has been analyzed. Further, analysis on φ and ψ angle variation, conservation, stability, and solvent accessibility have been performed on binding site residues. Knowledge obtained from the present study could be effectively employed in the protein-protein modeling and docking studies.
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Affiliation(s)
- N Saranya
- a Department of Bioinformatics , School of Life Sciences, Bharathidasan University , Tiruchirappalli 620024 , India.,b Department of Plant Molecular Biology and Bioinformatics , Tamil Nadu Agricultural University , Coimbatore , Tamil Nadu 641003 , India
| | - K M Saravanan
- a Department of Bioinformatics , School of Life Sciences, Bharathidasan University , Tiruchirappalli 620024 , India.,c Center of Excellence in Bioinformatics, School of Biotechnology , Madurai Kamaraj University , Madurai , Tamil Nadu 625 021 , India
| | - M Michael Gromiha
- d Department of Biotechnology , Indian Institute of Technology Madras , Chennai , Tamil Nadu 600036 , India
| | - S Selvaraj
- a Department of Bioinformatics , School of Life Sciences, Bharathidasan University , Tiruchirappalli 620024 , India
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Gupta AM, Pal P, Mandal S. Structural analysis of sigma E interactions with core RNA polymerase and its cognate P-hsp20 promoter of Mycobacterium tuberculosis. J Biomol Struct Dyn 2015; 34:792-9. [PMID: 26006066 DOI: 10.1080/07391102.2015.1054432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Alternate sigma factor plays an important role for the survival of Mycobacterium tuberculosis in adverse environmental condition. Stress-induced sigma factors are major cause for expression of genes involved in pathogenesis, dormancy and various unusual environmental conditions. In the present work, an attempt has been made to characterize one of such M. tuberculosis (Mtb) sigma factor, SigE. The structures of Mtb-SigE and Mtb-β have been predicted using comparative modelling techniques and validated. Effort has also been implied to understand the nature of interaction of SigE with the core RNA polymerase subunits which have well identified the amino acid residues in the binding interface and prompted the fact that Mtb-β' and Mtb-β interact with domain 2 and domain 4 of Mtb-SigE, respectively. Furthermore, intermolecular docking study predicted the interface between the Mtb-SigE and its putative promoter P-hsp20. The report confers the probable amino acid residues and the nitrogenous bases involved in the recognition of P-hsp20 by the sigma factor to initiate the transcription process.
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Affiliation(s)
- Aayatti Mallick Gupta
- a Department of Microbiology , University of Calcutta , 35, Ballygunge Circular Road, Kolkata 700019 , India
| | - Purab Pal
- a Department of Microbiology , University of Calcutta , 35, Ballygunge Circular Road, Kolkata 700019 , India
| | - Sukhendu Mandal
- a Department of Microbiology , University of Calcutta , 35, Ballygunge Circular Road, Kolkata 700019 , India
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Trejo-Soto PJ, Aguayo-Ortiz R, Yépez-Mulia L, Hernández-Campos A, Medina-Franco JL, Castillo R. Insights into the structure and inhibition of Giardia intestinalis arginine deiminase: homology modeling, docking, and molecular dynamics studies. J Biomol Struct Dyn 2015; 34:732-48. [PMID: 26017138 DOI: 10.1080/07391102.2015.1051115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Giardia intestinalis arginine deiminase (GiADI) is an important metabolic enzyme involved in the energy production and defense of this protozoan parasite. The lack of this enzyme in the human host makes GiADI an attractive target for drug design against G. intestinalis. One approach in the design of inhibitors of GiADI could be computer-assisted studies of its crystal structure, such as docking; however, the required crystallographic structure of the enzyme still remains unresolved. Because of its relevance, in this work, we present a three-dimensional structure of GiADI obtained from its amino acid sequence using the homology modeling approximation. Furthermore, we present an approximation of the most stable dimeric structure of GiADI identified through molecular dynamics simulation studies. An in silico analysis of druggability using the structure of GiADI was carried out in order to know if it is a good target for design and optimization of selective inhibitors. Potential GiADI inhibitors were identified by docking of a set of 3196 commercial and 19 in-house benzimidazole derivatives, and molecular dynamics simulation studies were used to evaluate the stability of the ligand-enzyme complexes.
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Affiliation(s)
- Pedro Josué Trejo-Soto
- a Facultad de Química, Departamento de Farmacia , Universidad Nacional Autónoma de México , México, DF 04510 , Mexico
| | - Rodrigo Aguayo-Ortiz
- a Facultad de Química, Departamento de Farmacia , Universidad Nacional Autónoma de México , México, DF 04510 , Mexico
| | - Lilián Yépez-Mulia
- b Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, IMSS , México, DF 06720 , Mexico
| | - Alicia Hernández-Campos
- a Facultad de Química, Departamento de Farmacia , Universidad Nacional Autónoma de México , México, DF 04510 , Mexico
| | - José Luis Medina-Franco
- a Facultad de Química, Departamento de Farmacia , Universidad Nacional Autónoma de México , México, DF 04510 , Mexico
| | - Rafael Castillo
- a Facultad de Química, Departamento de Farmacia , Universidad Nacional Autónoma de México , México, DF 04510 , Mexico
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Advani P, Joseph B, Ambre P, Pissurlenkar R, Khedkar V, Iyer K, Gabhe S, Iyer RP, Coutinho E. In silico optimization of pharmacokinetic properties and receptor binding affinity simultaneously: a 'parallel progression approach to drug design' applied to β-blockers. J Biomol Struct Dyn 2015; 34:384-98. [PMID: 25854164 DOI: 10.1080/07391102.2015.1033646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The present work exploits the potential of in silico approaches for minimizing attrition of leads in the later stages of drug development. We propose a theoretical approach, wherein 'parallel' information is generated to simultaneously optimize the pharmacokinetics (PK) and pharmacodynamics (PD) of lead candidates. β-blockers, though in use for many years, have suboptimal PKs; hence are an ideal test series for the 'parallel progression approach'. This approach utilizes molecular modeling tools viz. hologram quantitative structure activity relationships, homology modeling, docking, predictive metabolism, and toxicity models. Validated models have been developed for PK parameters such as volume of distribution (log Vd) and clearance (log Cl), which together influence the half-life (t1/2) of a drug. Simultaneously, models for PD in terms of inhibition constant pKi have been developed. Thus, PK and PD properties of β-blockers were concurrently analyzed and after iterative cycling, modifications were proposed that lead to compounds with optimized PK and PD. We report some of the resultant re-engineered β-blockers with improved half-lives and pKi values comparable with marketed β-blockers. These were further analyzed by the docking studies to evaluate their binding poses. Finally, metabolic and toxicological assessment of these molecules was done through in silico methods. The strategy proposed herein has potential universal applicability, and can be used in any drug discovery scenario; provided that the data used is consistent in terms of experimental conditions, endpoints, and methods employed. Thus the 'parallel progression approach' helps to simultaneously fine-tune various properties of the drug and would be an invaluable tool during the drug development process.
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Affiliation(s)
- Poonam Advani
- a Department of Pharmaceutical Chemistry , C.U. Shah College of Pharmacy, S.N.D.T. Women's University , Mumbai , Maharashtra , India.,e Mumbai Educational Trust , Institute of Pharmacy , Bandra Reclamation, Bandra (W), Mumbai , India
| | - Blessy Joseph
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
| | - Premlata Ambre
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
| | - Raghuvir Pissurlenkar
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
| | - Vijay Khedkar
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
| | - Krishna Iyer
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
| | - Satish Gabhe
- c Department of Pharmaceutical Chemistry , Poona College of Pharmacy, Bharati Vidyapeeth Deemed University , Pune , India
| | | | - Evans Coutinho
- b Department of Pharmaceutical Chemistry , Bombay College of Pharmacy , Mumbai , Maharashtra , India
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58
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Biswal HS, Bhattacharyya S, Bhattacherjee A, Wategaonkar S. Nature and strength of sulfur-centred hydrogen bonds: laser spectroscopic investigations in the gas phase and quantum-chemical calculations. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1022946] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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59
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Wilson KA, Wells RA, Abendong MN, Anderson CB, Kung RW, Wetmore SD. Landscape of π-π and sugar-π contacts in DNA-protein interactions. J Biomol Struct Dyn 2015; 34:184-200. [PMID: 25723403 DOI: 10.1080/07391102.2015.1013157] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
There were 1765 contacts identified between DNA nucleobases or deoxyribose and cyclic (W, H, F, Y) or acyclic (R, E, D) amino acids in 672 X-ray structures of DNA-protein complexes. In this first study to compare π-interactions between the cyclic and acyclic amino acids, visual inspection was used to categorize amino acid interactions as nucleobase π-π (according to biological edge) or deoxyribose sugar-π (according to sugar edge). Overall, 54% of contacts are nucleobase π-π interactions, which involve all amino acids, but are more common for Y, F, and R, and involve all DNA nucleobases with similar frequencies. Among binding arrangements, cyclic amino acids prefer more planar (stacked) π-systems than the acyclic counterparts. Although sugar-π interactions were only previously identified with the cyclic amino acids and were found to be less common (38%) than nucleobase-cyclic amino acid contacts, sugar-π interactions are more common than nucleobase π-π contacts for the acyclic series (61% of contacts). Similar to DNA-protein π-π interactions, sugar-π contacts most frequently involve Y and R, although all amino acids adopt many binding orientations relative to deoxyribose. These DNA-protein π-interactions stabilize biological systems, by up to approximately -40 kJ mol(-1) for neutral nucleobase or sugar-amino acid interactions, but up to approximately -95 kJ mol(-1) for positively or negatively charged contacts. The high frequency and strength, despite variation in structure and composition, of these π-interactions point to an important function in biological systems.
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Affiliation(s)
- Katie A Wilson
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
| | - Rachael A Wells
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
| | - Minette N Abendong
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
| | - Colin B Anderson
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
| | - Ryan W Kung
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
| | - Stacey D Wetmore
- a Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West, Lethbridge , AB T1K 3M4 , Canada
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60
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Kumar V, Damodharan S, Pandaranayaka EP, Madathiparambil MG, Tennyson J. Molecular modeling andin-silicoengineering ofCardamom mosaic viruscoat protein for the presentation of immunogenic epitopes ofLeptospiraLipL32. J Biomol Struct Dyn 2015; 34:42-56. [DOI: 10.1080/07391102.2015.1009491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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61
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Benrezkallah D, Dauchez M, Krallafa A. Molecular dynamics of the salt dependence of a cold-adapted enzyme: endonuclease I. J Biomol Struct Dyn 2015; 33:2511-21. [DOI: 10.1080/07391102.2014.1002007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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62
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Gorai B, Prabhavadhni A, Sivaraman T. Unfolding stabilities of two structurally similar proteins as probed by temperature-induced and force-induced molecular dynamics simulations. J Biomol Struct Dyn 2014; 33:2037-47. [DOI: 10.1080/07391102.2014.986668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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63
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Khorsand Ahmadi S, Mahmoodian Moghadam M, Mokaberi P, Reza Saberi M, Chamani J. A comparison study of the interaction between β-lactoglobulin and retinol at two different conditions: spectroscopic and molecular modeling approaches. J Biomol Struct Dyn 2014; 33:1880-98. [DOI: 10.1080/07391102.2014.977351] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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64
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Ratnaparkhi A, Muthu SA, Shiriskar SM, Pissurlenkar RR, Choudhary S, Ahmad B. Effects of hesperidin, a flavanone glycoside interaction on the conformation, stability, and aggregation of lysozyme: multispectroscopic and molecular dynamic simulation studies? J Biomol Struct Dyn 2014; 33:1866-79. [DOI: 10.1080/07391102.2014.975746] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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65
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Lavanya P, Ramaiah S, Anbarasu A. Binding site residues in β-lactamases: role in non-classical interactions and metal binding. J COORD CHEM 2014. [DOI: 10.1080/00958972.2014.956661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- P. Lavanya
- Medical & Biological Computing Laboratory, School of Biosciences and Technology, VIT University, Vellore, India
| | - Sudha Ramaiah
- Medical & Biological Computing Laboratory, School of Biosciences and Technology, VIT University, Vellore, India
| | - Anand Anbarasu
- Medical & Biological Computing Laboratory, School of Biosciences and Technology, VIT University, Vellore, India
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66
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Mandal RS, Das S. In silicoapproach towards identification of potential inhibitors ofHelicobacter pyloriDapE. J Biomol Struct Dyn 2014; 33:1460-73. [DOI: 10.1080/07391102.2014.954272] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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67
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Banerjee R, Chakraborti P, Bhowmick R, Mukhopadhyay S. Distinct molecular features facilitating ice-binding mechanisms in hyperactive antifreeze proteins closely related to an Antarctic sea ice bacterium. J Biomol Struct Dyn 2014; 33:1424-41. [PMID: 25190099 DOI: 10.1080/07391102.2014.952665] [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: 10/24/2022]
Abstract
Antifreeze proteins or ice-binding proteins (IBPs) facilitate the survival of certain cellular organisms in freezing environment by inhibiting the growth of ice crystals in solution. Present study identifies orthologs of the IBP of Colwellia sp. SLW05, which were obtained from a wide range of taxa. Phylogenetic analysis on the basis of conserved regions (predicted as the 'ice-binding domain' [IBD]) present in all the orthologs, separates the bacterial and archaeal orthologs from that of the eukaryotes'. Correspondence analysis pointed out that the bacterial and archaeal IBDs have relatively higher average hydrophobicity than the eukaryotic members. IBDs belonging to bacterial as well as archaeal AFPs contain comparatively more strands, and therefore are revealed to be under higher evolutionary selection pressure. Molecular docking studies prove that the ice crystals form more stable complex with the bacterial as well as archaeal proteins than the eukaryotic orthologs. Analysis of the docked structures have traced out the ice-binding sites (IBSs) in all the orthologs which continue to facilitate ice-binding activity even after getting mutated with respect to the well-studied IBSs of Typhula ishikariensis and notably, all these mutations performing ice-binding using 'anchored clathrate mechanism' have been found to prefer polar and hydrophilic amino acids. Horizontal gene transfer studies point toward a strong selection pressure favoring independent evolution of the IBPs in some polar organisms including prokaryotes as well as eukaryotes because these proteins facilitate the polar organisms to acclimatize to the adversities in their niche, thus safeguarding their existence.
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Affiliation(s)
- Rachana Banerjee
- a Department of Biophysics, Molecular Biology and Bioinformatics , University of Calcutta , 92, A.P.C. Road, Kolkata 700009 , India
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Jahandideh S, Jamalan M, Faridounnia M. Molecular dynamics study of the dominant-negative E219K polymorphism in human prion protein. J Biomol Struct Dyn 2014; 33:1315-25. [DOI: 10.1080/07391102.2014.945486] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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69
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Kaneko K, Washio K, Umezawa T, Matsuda F, Morikawa M, Okino T. cDNA cloning and characterization of vanadium-dependent bromoperoxidases from the red alga Laurencia nipponica. Biosci Biotechnol Biochem 2014; 78:1310-9. [DOI: 10.1080/09168451.2014.918482] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their Km values for Br− were significantly lower than other red algal VBPOs. The bromination reaction was also assessed using laurediol, the predicted natural precursor of the brominated ether laurencin. Laurediol, protected by trimethylsilyl at the enyne, was converted to deacetyllaurencin by the LnVBPOs, which was confirmed by tandem mass spectrometry. Native LnVBPO partially purified from algal bodies was active, suggesting that LnVBPO is functional in vivo. These results contributed to our knowledge of the biosynthesis of Laurencia brominated metabolites.
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Affiliation(s)
- Kensuke Kaneko
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Kenji Washio
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Taiki Umezawa
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Fuyuhiko Matsuda
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Masaaki Morikawa
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Tatsufumi Okino
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
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70
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Zhang Z, Chen X, Guan X, Liu Y, Chen H, Wang T, Mouekouba LDO, Li J, Wang A. A genome-wide survey of homeodomain-leucine zipper genes and analysis of cold-responsive HD-Zip I members’ expression in tomato. Biosci Biotechnol Biochem 2014; 78:1337-49. [DOI: 10.1080/09168451.2014.923292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Abstract
Homeodomain-leucine zipper (HD-Zip) proteins are a kind of transcriptional factors that play a vital role in plant growth and development. However, no detailed information of HD-Zip family in tomato has been reported till now. In this study, 51 HD-Zip genes (SlHZ01-51) in this family were identified and categorized into 4 classes by exon–intron and protein structure in tomato (Solanum lycopersicum) genome. The synthetical phylogenetic tree of tomato, Arabidopsis and rice HD-Zip genes were established for an insight into their evolutionary relationships and putative functions. The results showed that the contribution of segmental duplication was larger than that of tandem duplication for expansion and evolution of genes in this family of tomato. The expression profile results under abiotic stress suggested that all SlHZ I genes were responsive to cold stress. This study will provide a clue for the further investigation of functional identification and the role of tomato HD-Zip I subfamily in plant cold stress responses and developmental events.
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Affiliation(s)
- Zhenzhu Zhang
- College of Life Science, Northeast Agricultural University, Harbin, P.R. China
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, P.R. China
| | - Xiuling Chen
- College of Horticulture, Northeast Agricultural University, Harbin, P.R. China
| | - Xin Guan
- College of Horticulture, Northeast Agricultural University, Harbin, P.R. China
| | - Yang Liu
- College of Life Science, Northeast Agricultural University, Harbin, P.R. China
| | - Hongyu Chen
- College of Life Science, Northeast Agricultural University, Harbin, P.R. China
| | - Tingting Wang
- College of Horticulture, Northeast Agricultural University, Harbin, P.R. China
| | | | - Jingfu Li
- College of Horticulture, Northeast Agricultural University, Harbin, P.R. China
| | - Aoxue Wang
- College of Life Science, Northeast Agricultural University, Harbin, P.R. China
- College of Horticulture, Northeast Agricultural University, Harbin, P.R. China
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71
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Paulin S, Jamshad M, Dafforn TR, Garcia-Lara J, Foster SJ, Galley NF, Roper DI, Rosado H, Taylor PW. Surfactant-free purification of membrane protein complexes from bacteria: application to the staphylococcal penicillin-binding protein complex PBP2/PBP2a. NANOTECHNOLOGY 2014; 25:285101. [PMID: 24972373 DOI: 10.1088/0957-4484/25/28/285101] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Surfactant-mediated removal of proteins from biomembranes invariably results in partial or complete loss of function and disassembly of multi-protein complexes. We determined the capacity of styrene-co-maleic acid (SMA) co-polymer to remove components of the cell division machinery from the membrane of drug-resistant staphylococcal cells. SMA-lipid nanoparticles solubilized FtsZ-PBP2-PBP2a complexes from intact cells, demonstrating the close physical proximity of these proteins within the lipid bilayer. Exposure of bacteria to (-)-epicatechin gallate, a polyphenolic agent that abolishes β-lactam resistance in staphylococci, disrupted the association between PBP2 and PBP2a. Thus, SMA purification provides a means to remove native integral membrane protein assemblages with minimal physical disruption and shows promise as a tool for the interrogation of molecular aspects of bacterial membrane protein structure and function.
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Affiliation(s)
- Sarah Paulin
- School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK
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72
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Ali MR, Latif R, Davies TF, Mezei M. Monte Carlo loop refinement and virtual screening of the thyroid-stimulating hormone receptor transmembrane domain. J Biomol Struct Dyn 2014; 33:1140-52. [PMID: 25012978 DOI: 10.1080/07391102.2014.932310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Metropolis Monte Carlo (MMC) loop refinement has been performed on the three extracellular loops (ECLs) of rhodopsin and opsin-based homology models of the thyroid-stimulating hormone receptor transmembrane domain, a class A type G protein-coupled receptor. The Monte Carlo sampling technique, employing torsion angles of amino acid side chains and local moves for the six consecutive backbone torsion angles, has previously reproduced the conformation of several loops with known crystal structures with accuracy consistently less than 2 Å. A grid-based potential map, which includes van der Waals, electrostatics, hydrophobic as well as hydrogen-bond potentials for bulk protein environment and the solvation effect, has been used to significantly reduce the computational cost of energy evaluation. A modified sigmoidal distance-dependent dielectric function has been implemented in conjunction with the desolvation and hydrogen-bonding terms. A long high-temperature simulation with 2 kcal/mol repulsion potential resulted in extensive sampling of the conformational space. The slow annealing leading to the low-energy structures predicted secondary structure by the MMC technique. Molecular docking with the reported agonist reproduced the binding site within 1.5 Å. Virtual screening performed on the three lowest structures showed that the ligand-binding mode in the inter-helical region is dependent on the ECL conformations.
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Affiliation(s)
- M Rejwan Ali
- a Thyroid Research Unit , Icahn School of Medicine at Mount Sinai , New York , NY , USA
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73
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San Martín A, Sotelo-Hitschfeld T, Lerchundi R, Fernández-Moncada I, Ceballo S, Valdebenito R, Baeza-Lehnert F, Alegría K, Contreras-Baeza Y, Garrido-Gerter P, Romero-Gómez I, Barros LF. Single-cell imaging tools for brain energy metabolism: a review. NEUROPHOTONICS 2014; 1:011004. [PMID: 26157964 PMCID: PMC4478754 DOI: 10.1117/1.nph.1.1.011004] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 05/03/2023]
Abstract
Neurophotonics comes to light at a time in which advances in microscopy and improved calcium reporters are paving the way toward high-resolution functional mapping of the brain. This review relates to a parallel revolution in metabolism. We argue that metabolism needs to be approached both in vitro and in vivo, and that it does not just exist as a low-level platform but is also a relevant player in information processing. In recent years, genetically encoded fluorescent nanosensors have been introduced to measure glucose, glutamate, ATP, NADH, lactate, and pyruvate in mammalian cells. Reporting relative metabolite levels, absolute concentrations, and metabolic fluxes, these sensors are instrumental for the discovery of new molecular mechanisms. Sensors continue to be developed, which together with a continued improvement in protein expression strategies and new imaging technologies, herald an exciting era of high-resolution characterization of metabolism in the brain and other organs.
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Affiliation(s)
- Alejandro San Martín
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Tamara Sotelo-Hitschfeld
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Rodrigo Lerchundi
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Ignacio Fernández-Moncada
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Sebastian Ceballo
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | - Rocío Valdebenito
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | | | - Karin Alegría
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | - Yasna Contreras-Baeza
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Pamela Garrido-Gerter
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Ignacio Romero-Gómez
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - L. Felipe Barros
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Address all correspondence to: L. Felipe Barros, E-mail:
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74
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Brovarets' OO, Hovorun DM. The nature of the transition mismatches with Watson-Crick architecture: the G*·T or G·T* DNA base mispair or both? A QM/QTAIM perspective for the biological problem. J Biomol Struct Dyn 2014; 33:925-45. [PMID: 24842163 DOI: 10.1080/07391102.2014.924879] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This study provides the first accurate investigation of the tautomerization of the biologically important guanine*·thymine (G*·T) DNA base mispair with Watson-Crick geometry, involving the enol mutagenic tautomer of the G and the keto tautomer of the T, into the G·T* mispair (∆G = .99 kcal mol(-1), population = 15.8% obtained at the MP2 level of quantum-mechanical theory in the continuum with ε = 4), formed by the keto tautomer of the G and the enol mutagenic tautomer of the T base, using DFT and MP2 methods in vacuum and in the weakly polar medium (ε = 4), characteristic for the hydrophobic interfaces of specific protein-nucleic acid interactions. We were first able to show that the G*·T↔G·T* tautomerization occurs through the asynchronous concerted double proton transfer along two antiparallel O6H···O4 and N1···HN3 H-bonds and is assisted by the third N2H···O2 H-bond, that exists along the entire reaction pathway. The obtained results indicate that the G·T* base mispair is stable from the thermodynamic point of view complex, while it is dynamically unstable structure in vacuum and dynamically stable structure in the continuum with ε = 4 with lifetime of 6.4·10(-12) s, that, on the one side, makes it possible to develop all six low-frequency intermolecular vibrations, but, on the other side, it is by three orders less than the time (several ns) required for the replication machinery to forcibly dissociate a base pair into the monomers during DNA replication. One of the more significant findings to emerge from this study is that the short-lived G·T* base mispair, which electronic interaction energy between the bases (-23.76 kcal mol(-1)) exceeds the analogical value for the G·C Watson-Crick nucleobase pair (-20.38 kcal mol(-1)), "escapes from the hands" of the DNA replication machinery by fast transforming into the G*·T mismatch playing an indirect role of its supplier during the DNA replication. So, exactly the G*·T mismatch was established to play the crucial role in the spontaneous point mutagenesis.
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Affiliation(s)
- Ol'ha O Brovarets'
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Akademika Zabolotnoho Str., Kyiv 03680 , Ukraine
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75
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Yamaguchi M, Takai S, Hosono A, Seki T. Bovine milk-derived α-lactalbumin inhibits colon inflammation and carcinogenesis in azoxymethane and dextran sodium sulfate-treated mice. Biosci Biotechnol Biochem 2014; 78:672-9. [PMID: 25036966 DOI: 10.1080/09168451.2014.890034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cyclooxygenase-2 is expressed early in colon carcinogenesis and plays crucial role in the progress of the disease. Recently, we found that α-lactalbumin had anti-inflammatory activity by inhibiting cyclooxygenase-2. In experiment 1, we investigated the effects of α-lactalbumin on the colon carcinogenesis initiated with azoxymethane (AOM) followed by promotion with dextran sodium sulfate (DSS) in mice. Dietary treatment with α-lactalbumin decreased fecal occult blood score at 3 days after DSS intake. α-Lactalbumin also decreased the colon tumor at week 9. In experiment 2, AOM-treated mice were sacrificed at 7 days after DSS intake. The plasma and colon prostaglandin E2 (PGE2) levels in AOM/DSS-treated mice were higher than those in the DSS-treated mice without initiation by AOM. α-Lactalbumin decreased PGE2 in both plasma and colon. These results suggest that α-lactalbumin effectively inhibited colon carcinogenesis, and the inhibition may be due to the decreased PGE2 by inhibiting cyclooxygenase-2 at cancer promotion stages.
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Affiliation(s)
- Makoto Yamaguchi
- a Food Science Research Labs, R&D Division, Meiji Co., Ltd. , Odawara , Japan
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76
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Rahman GM, Das J. Modeling studies on the structural determinants for the DAG/phorbol ester binding to C1 domain. J Biomol Struct Dyn 2014; 33:219-32. [DOI: 10.1080/07391102.2014.895679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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77
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Maity A, Majumdar S, Priya P, De P, Saha S, Ghosh Dastidar S. Adaptability in protein structures: structural dynamics and implications in ligand design. J Biomol Struct Dyn 2014; 33:298-321. [PMID: 24433438 DOI: 10.1080/07391102.2013.873002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The basic framework of understanding the mechanisms of protein functions is achieved from the knowledge of their structures which can model the molecular recognition. Recent advancement in the structural biology has revealed that in spite of the availability of the structural data, it is nontrivial to predict the mechanism of the molecular recognition which progresses via situation-dependent structural adaptation. The mutual selectivity of protein-protein and protein-ligand interactions often depends on the modulations of conformations empowered by their inherent flexibility, which in turn regulates the function. The mechanism of a protein's function, which used to be explained by the ideas of 'lock and key' has evolved today as the concept of 'induced fit' as well as the 'population shift' models. It is felt that the 'dynamics' is an essential feature to take into account for understanding the mechanism of protein's function. The design principles of therapeutic molecules suffer from the problems of plasticity of the receptors whose binding conformations are accurately not predictable from the prior knowledge of a template structure. On the other hand, flexibility of the receptors provides the opportunity to improve the binding affinity of a ligand by suitable substitution that will maximize the binding by modulating the receptors surface. In this paper, we discuss with example how the protein's flexibility is correlated with its functions in various systems, revealing the importance of its understanding and for making applications. We also highlight the methodological challenges to investigate it computationally and to account for the flexible nature of the molecules in drug design.
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Affiliation(s)
- Atanu Maity
- a Bioinformatics Centre, Bose Institute , P-1/12, C.I.T. Scheme VII M, Kolkata 700054 , India
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78
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Brovarets’ OO, Hovorun DM. The physicochemical essence of the purine·pyrimidine transition mismatches with Watson-Crick geometry in DNA: A·C*versaA*·C. A QM and QTAIM atomistic understanding. J Biomol Struct Dyn 2013; 33:28-55. [DOI: 10.1080/07391102.2013.852133] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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79
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D’Ursi P, Orro A, Morra G, Moscatelli M, Trombetti G, Milanesi L, Rovida E. Molecular dynamics and docking simulation of a natural variant of Activated Protein C with impaired protease activity: implications for integrin-mediated antiseptic function. J Biomol Struct Dyn 2013; 33:85-92. [DOI: 10.1080/07391102.2013.851033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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80
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Beier C, Zacharias M. Tackling the challenges posed by target flexibility in drug design. Expert Opin Drug Discov 2012; 5:347-59. [PMID: 22823087 DOI: 10.1517/17460441003713462] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Current computational docking methods are often effective in predicting accurate drug-binding geometries in cases of relatively rigid target structures. However, binding of drug-like ligands to protein receptor molecules frequently involves or even requires conformational adaptation. Realistic prediction of ligand-receptor binding geometries and complex stability needs in many cases an appropriate inclusion of conformational changes, not only for the ligand, but also for the receptor molecule. AREAS COVERED IN THIS REVIEW Recent approaches to efficiently account for target receptor flexibility during docking simulations are reviewed. WHAT THE READER WILL GAIN The reader will gain insights into methods to efficiently treat protein side-chain flexibility and approaches for continuous adaptation of backbone conformations in pre-calculated essential or soft collective degrees of freedom. In addition, molecular dynamics or Monte Carlo based methods providing simultaneous inclusion of receptor and ligand flexibility are discussed as well as promising new developments to generate conformationally diverse ensembles of a protein structure. The large variety of possible conformational changes in proteins on ligand binding is illustrated for the enzyme reverse transcriptase of HIV-1, which is an important drug target. TAKE HOME MESSAGE If the backbone conformation of the binding site does not change, current docking programs can perform well by taking side-chain reorientations into account only. Future progress to account for full target flexibility in docking requires both accurate prediction of the essential modes of backbone motion and improvements in scoring to enhance selectivity. Thus, the scoring function should realistically cover energetic and particularly entropic contributions to binding, which would allow more realistic estimates of binding free energies.
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Affiliation(s)
- Christian Beier
- Jacobs University Bremen, School of Engineering and Science, Campus Ring 1, D-28759 Bremen, Germany
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81
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Seitz A, Terjung S, Zimmermann T, Pepperkok R. Quantifying the influence of yellow fluorescent protein photoconversion on acceptor photobleaching-based fluorescence resonance energy transfer measurements. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:011010. [PMID: 22352644 DOI: 10.1117/1.jbo.17.1.011010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fluorescence resonance energy transfer (FRET) efficiency measurements based on acceptor photobleaching of yellow fluorescent protein (YFP) are affected by the fact that bleaching of YFP produces a fluorescent species that is detectable in cyan fluorescent protein (CFP) image channels. The presented quantitative measurement of this conversion makes it possible to correct the obtained FRET signal to increase the accuracy of intensity based CFP/YFP FRET measurements. The described method can additionally be used to compare samples with very different fluorescence levels.
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Affiliation(s)
- Arne Seitz
- European Molecular Biology Laboratory, Advanced Light Microscopy Facility, Meyerhofstr 1, 69117 Heidelberg, Germany.
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82
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DiSalvo S, Serio TR. Insights into prion biology: integrating a protein misfolding pathway with its cellular environment. Prion 2011; 5:76-83. [PMID: 21654204 DOI: 10.4161/pri.5.2.16413] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Protein misfolding and assembly into ordered, self-templating aggregates (amyloid) has emerged as a novel mechanism for regulating protein function. For a subclass of amyloidogenic proteins known as prions, this process induces transmissible changes in normal cellular physiology, ranging from neurodegenerative disease in animals and humans to new traits in fungi. The severity and stability of these altered phenotypic states can be attenuated by the conformation or amino-acid sequence of the prion, but in most of these cases, the protein retains the ability to form amyloid in vitro. Thus, our ability to link amyloid formation in vitro with its biological consequences in vivo remains a challenge. In two recent studies, we have begun to address this disconnect by assessing the effects of the cellular environment on traits associated with the misfolding of the yeast prion Sup35. Remarkably, the effects of quality control pathways and of limitations on protein transfer in vivo amplify the effects of even slight differences in the efficiency of Sup35 misfolding, leading to dramatic changes in the associated phenotype. Together, our studies suggest that the interplay between protein misfolding pathways and their cellular context is a crucial contributor to prion biology.
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Affiliation(s)
- Susanne DiSalvo
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
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83
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Kobayashi A, Hizume M, Teruya K, Mohri S, Kitamoto T. Heterozygous inhibition in prion infection: the stone fence model. Prion 2009; 3:27-30. [PMID: 19372732 DOI: 10.4161/pri.3.1.8514] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The human PrP gene (PRNP) has two major polymorphic codons: 129 for methionine (M) or valine (V) and 219 for glutamate (E) or lysine (K). The PRNP heterozygotes appear to be protected from sporadic CJD compared to the PRNP homozygotes. The molecular mechanism responsible for these protective effects of PRNP heterozygosity has remained elusive. In this review, we describe the inhibition of PrP conversion observed in a series of transmission studies using PRNP heterozygous animal models. In vCJD infection, the conversion incompetent human PrP 129V molecules showed an inhibitory effect on the conversion of human PrP 129M molecules in the 129M/V heterozygous mice. Furthermore, though the human PrP 219E and PrP 219K were both conversion competent in vCJD infection, these conversion competent PrP molecules showed an inhibitory effect in the 219E/K heterozygous animals. To explain this heterozygous inhibition, we propose a possible mechanism designated as the stone fence model.
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Affiliation(s)
- Atsushi Kobayashi
- Division of CJD Science and Technology, Department of Prion Research, Tohoku University Graduate School of Medicine, Sendai, Japan
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