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Some Clues about Enzymes from Psychrophilic Microorganisms. Microorganisms 2022; 10:microorganisms10061161. [PMID: 35744679 PMCID: PMC9227589 DOI: 10.3390/microorganisms10061161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/29/2022] [Accepted: 06/03/2022] [Indexed: 02/04/2023] Open
Abstract
Enzymes purified from psychrophilic microorganisms prove to be efficient catalysts at low temperatures and possess a great potential for biotechnological applications. The low-temperature catalytic activity has to come from specific structural fluctuations involving the active site region, however, the relationship between protein conformational stability and enzymatic activity is subtle. We provide a survey of the thermodynamic stability of globular proteins and their rationalization grounded in a theoretical approach devised by one of us. Furthermore, we provide a link between marginal conformational stability and protein flexibility grounded in the harmonic approximation of the vibrational degrees of freedom, emphasizing the occurrence of long-wavelength and excited vibrations in all globular proteins. Finally, we offer a close view of three enzymes: chloride-dependent α-amylase, citrate synthase, and β-galactosidase.
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Mohsin I, Zhang LQ, Li DC, Papageorgiou AC. Crystal structure of a Cu,Zn superoxide dismutase from the thermophilic fungus Chaetomium thermophilum. Protein Pept Lett 2021; 28:1043-1053. [PMID: 33726638 DOI: 10.2174/0929866528666210316104919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Thermophilic fungi have recently emerged as a promising source of thermostable enzymes. Superoxide dismutases are key antioxidant metalloenzymes with promising therapeutic effects in various diseases, both acute and chronic. However, structural heterogeneity and low thermostability limit their therapeutic efficacy. OBJECTIVE Although several studies from hypethermophilic superoxide dismutases (SODs) have been reported, information about Cu,Zn-SODs from thermophilic fungi is scarce. Chaetomium thermophilum is a thermophilic fungus that could provide proteins with thermophilic properties. METHOD The enzyme was expressed in Pichia pastoris cells and crystallized using the vapor-diffusion method. X-ray data were collected, and the structure was determined and refined to 1.56 Å resolution. Structural analysis and comparisons were carried out. RESULTS The presence of 8 molecules (A through H) in the asymmetric unit resulted in four different interfaces. Molecules A and F form the typical homodimer which is also found in other Cu,Zn-SODs. Zinc was present in all subunits of the structure while copper was found in only four subunits with reduced occupancy (C, D, E and F). CONCLUSION The ability of the enzyme to form oligomers and the elevated Thr:Ser ratio may be contributing factors to its thermal stability. Two hydrophobic residues that participate in interface formation and are not present in other CuZn-SODs may play a role in the formation of new interfaces and the oligomerization process. The CtSOD crystal structure reported here is the first Cu,Zn-SOD structure from a thermophilic fungus.
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Affiliation(s)
- Imran Mohsin
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku 20521. Finland
| | - Li-Qing Zhang
- Department of Mycology, Shandong Agricultural University, Taian, Shandong 271018. China
| | - Duo-Chuan Li
- Department of Mycology, Shandong Agricultural University, Taian, Shandong 271018. China
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4-Hydroxyphenylpyruvate Dioxygenase Thermolability Is Responsible for Temperature-Dependent Melanogenesis in Aeromonas salmonicida subsp. salmonicida. Appl Environ Microbiol 2019; 85:AEM.01926-18. [PMID: 30341077 DOI: 10.1128/aem.01926-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/09/2018] [Indexed: 12/17/2022] Open
Abstract
Aeromonas salmonicida subsp. salmonicida is a major pathogen affecting fisheries worldwide and is a well-known pigmented member of the Aeromonas genus. This subspecies produces melanin at ≤22°C. However, melanogenesis decreases as the culture temperature increases and is completely suppressed at 30°C to 35°C, while bacterial growth is unaffected. The mechanism and biological significance of this temperature-dependent melanogenesis remain unclear. Heterologous expression of an A. salmonicida subsp. salmonicida 4-hydroxyphenylpyruvate dioxygenase (HppD), the most critical enzyme in the homogentisic acid (HGA)-melanin synthesis pathway, results in thermosensitive pigmentation in Escherichia coli, suggesting that HppD plays a key role in this process. In this study, we demonstrated that the thermolability of HppD is responsible for the temperature-dependent melanization of A. salmonicida subsp. salmonicida Substitutions of three residues, S18T, P103Q, and L119P, in A. salmonicida subsp. salmonicida HppD increased the thermostability of this enzyme and resulted in temperature-independent melanogenesis. Moreover, the replacement of the corresponding residues in HppD from Aeromonas media strain WS, which forms pigment independent of temperature, with those of A. salmonicida subsp. salmonicida HppD resulted in thermosensitive melanogenesis. A structural analysis suggested that mutations at these sites, especially at position P103, strengthen the secondary structure of HppD and greatly improve its thermal stability. Additionally, we found that the HppD sequences of all A. salmonicida subsp. salmonicida isolates were identical and that two of the three residues were clearly distinct from those of other Aeromonas strains.IMPORTANCE Aeromonas salmonicida subsp. salmonicida is the causative agent of furunculosis, a bacterial septicemia of cold-water fish of the Salmonidae family. Although other Aeromonas species can produce melanin, A. salmonicida subsp. salmonicida is the only member of this genus that has been reported to exhibit temperature-dependent melanization. Here, we demonstrated that thermosensitive melanogenesis in A. salmonicida subsp. salmonicida strains is due to the thermolability of 4-hydroxyphenylpyruvate dioxygenase (HppD). Additionally, we confirmed that this thermolabile HppD exhibited higher activity at low temperatures than its mesophilic homologues, suggesting this as an adaptive strategy of this enzyme to the psychrophilic lifestyle of A. salmonicida subsp. salmonicida The strictly conserved hppD sequences among A. salmonicida subsp. salmonicida isolates and the specific possession of P103 and L119 residues could be used as a reference for the identification of A. salmonicida subsp. salmonicida isolates.
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Zhang D, Hu P, Liu T, Wang J, Jiang S, Xu Q, Chen L. GC bias lead to increased small amino acids and random coils of proteins in cold-water fishes. BMC Genomics 2018; 19:315. [PMID: 29720106 PMCID: PMC5930961 DOI: 10.1186/s12864-018-4684-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/16/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Temperature adaptation of biological molecules is fundamental in evolutionary studies but remains unsolved. Fishes living in cold water are adapted to low temperatures through adaptive modification of their biological molecules, which enables their functioning in extreme cold. To study nucleotide and amino acid preference in cold-water fishes, we investigated the substitution asymmetry of codons and amino acids in protein-coding DNA sequences between cold-water fishes and tropical fishes., The former includes two Antarctic fishes, Dissostichus mawsoni (Antarctic toothfish), Gymnodraco acuticeps (Antarctic dragonfish), and two temperate fishes, Gadus morhua (Atlantic cod) and Gasterosteus aculeatus (stickleback), and the latter includes three tropical fishes, including Danio rerio (zebrafish), Oreochromis niloticus (Nile tilapia) and Xiphophorus maculatus (Platyfish). RESULTS Cold-water fishes showed preference for Guanines and cytosines (GCs) in both synonymous and nonsynonymous codon substitution when compared with tropical fishes. Amino acids coded by GC-rich codons are favored in the temperate fishes, while those coded by AT-rich codons are disfavored. Similar trends were discovered in Antarctic fishes but were statistically weaker. The preference of GC rich codons in nonsynonymous substitution tends to increase ratio of small amino acid in proteins, which was demonstrated by biased small amino acid substitutions in the cold-water species when compared with the tropical species, especially in the temperate species. Prediction and comparison of secondary structure of the proteomes showed that frequency of random coils are significantly larger in the cold-water fish proteomes than those of the tropical fishes. CONCLUSIONS Our results suggested that natural selection in cold temperature might favor biased GC content in the coding DNA sequences, which lead to increased frequency of small amino acids and consequently increased random coils in the proteomes of cold-water fishes.
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Affiliation(s)
- Dongsheng Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, People's Republic of China
| | - Peng Hu
- Department of Genetics, University of Pennsylvania, Philadelphia, USA
| | - Taigang Liu
- College of Informatics, Shanghai Ocean University, Shanghai, People's Republic of China
| | - Jian Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, People's Republic of China
| | - Shouwen Jiang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, People's Republic of China
| | - Qianghua Xu
- College of Marine Sciences, Shanghai Ocean University, Shanghai, People's Republic of China
| | - Liangbiao Chen
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, People's Republic of China.
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Jung YH, Uh JH, Lee K, Im H. An intrinsically disordered domain in Polaribacter irgensii KOPRI 22228 CspB confers extraordinary freeze-tolerance. Biochem Biophys Res Commun 2018; 496:374-380. [PMID: 29330047 DOI: 10.1016/j.bbrc.2018.01.050] [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: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 10/18/2022]
Abstract
Organisms living in extremely cold environments possess mechanisms to survive low temperatures. Among the known cold-induced genes, cold-shock proteins (Csps) are the most prominent. A csp-homologous gene, cspBPi, has been cloned from the Arctic bacterium Polaribacter irgensii KOPRI 22228, and overexpression of this gene greatly increased the freezing tolerance of its host. This protein consists of a unique N-terminal domain and a well conserved C-terminal cold shock domain. To elucidate the detailed mechanisms involved in the extraordinary freeze-tolerance conferred by CspBPi, we identified the responsible domain by mutational analysis. Changes of residues in the cold shock domain that are crucial for binding RNA or single-stranded DNA did not impair the ability of the host to survive freezing stress. All domain-shuffled CspBPi variants containing the N-terminal domain retained the ability to confer superior freeze-tolerance. Slow electrophoretic mobility and far-UV circular dichroism spectra of the N-terminal domain suggested an intrinsically disordered structure for this region. The N-terminal domain also bound to lipid vesicles in vitro. This lipid vesicle binding characteristic is shared with other intrinsically disordered proteins, such as α-synuclein and plant dehydrins, known to confer cold-tolerance when overexpressed, suggesting a mechanism for cold-survival through membrane binding.
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Affiliation(s)
- Youn Hong Jung
- Department of Molecular Biology, Sejong University, 209 Neungdong-ro, Gunja-dong, Gwangjin-gu, Seoul 05006, Republic of Korea
| | - Ji-Hyun Uh
- Department of Molecular Biology, Sejong University, 209 Neungdong-ro, Gunja-dong, Gwangjin-gu, Seoul 05006, Republic of Korea
| | - Kyunghee Lee
- Department of Chemistry, Sejong University, 209 Neungdong-ro, Gunja-dong, Gwangjin-gu, Seoul 05006, Republic of Korea
| | - Hana Im
- Department of Molecular Biology, Sejong University, 209 Neungdong-ro, Gunja-dong, Gwangjin-gu, Seoul 05006, Republic of Korea; Department of Integrative Bioscience and Biotechnology, Sejong University, 209 Neungdong-ro, Gunja-dong, Gwangjin-gu, Seoul 05006, Republic of Korea.
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Fullana N, Braña V, José Marizcurrena J, Morales D, Betton JM, Marín M, Castro-Sowinski S. Identification, recombinant production and partial biochemical characterization of an extracellular cold-active serine-metalloprotease from an Antarctic Pseudomonas isolate. AIMS BIOENGINEERING 2017. [DOI: 10.3934/bioeng.2017.3.386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Ferreras JM, Ragucci S, Citores L, Iglesias R, Pedone PV, Di Maro A. Insight into the phylogenetic relationship and structural features of vertebrate myoglobin family. Int J Biol Macromol 2016; 93:1041-1050. [PMID: 27659002 DOI: 10.1016/j.ijbiomac.2016.09.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/18/2016] [Indexed: 11/17/2022]
Abstract
Myoglobin (Mb) is studied to clarify the structure-function relationships in protein science. In this work, we report the results of a comparative analysis of amino acid sequences from 298 vertebrate Mbs. Forty-one high conserved residues were identified and seven of them were invariants [E18, G25, F43, V68, L72, H93 (proximal histidine) and H97]. E18 is the only invariant amino acid residue located out of the heme-pocket and Xe-cavities playing a role in interaction between the A and E-helices. A comparative analysis of several parameters related to amino acid composition shows an increase of average mass, accessible surface area and volume per residue from Actinopterygii to Mammalia and Aves. This may be due to an increased number of bulky residues reducing the non-specific cavities volume and thus improving the oxygen flow between the heme site and the outside of the protein. Finally, the phylogenetic analyses of Mb in vertebrates are consistent with an evolution that runs with the diversification of the species, but in which several episodes of gene duplication and lost have occurred, less frequently in the ancestors of great taxons, cartilaginous fishes and non-avian reptiles, most frequently in ray-finned fishes and mammals, and very frequently in birds.
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Affiliation(s)
- José M Ferreras
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain
| | - Sara Ragucci
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy
| | - Lucía Citores
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain
| | - Rosario Iglesias
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain
| | - Paolo V Pedone
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy
| | - Antimo Di Maro
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy.
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Novel S -enantioselective lipase TALipB from Trichosporon asahii MSR54: Heterologous expression, characterization, conformational stability and homology modeling. Enzyme Microb Technol 2016; 83:29-39. [DOI: 10.1016/j.enzmictec.2015.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/10/2015] [Accepted: 11/10/2015] [Indexed: 11/18/2022]
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Insights into the molecular basis of piezophilic adaptation: Extraction of piezophilic signatures. J Theor Biol 2015; 390:117-26. [PMID: 26656108 DOI: 10.1016/j.jtbi.2015.11.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 11/06/2015] [Accepted: 11/21/2015] [Indexed: 11/20/2022]
Abstract
Piezophiles are the organisms which can successfully survive at extreme pressure conditions. However, the molecular basis of piezophilic adaptation is still poorly understood. Analysis of the protein sequence adjustments that had taken place during evolution can help to reveal the sequence adaptation parameters responsible for protein functional and structural adaptation at such high pressure conditions. In this current work we have used SVM classifier for filtering strong instances and generated human interpretable rules from these strong instances by using the PART algorithm. These generated rules were analyzed for getting insights into the molecular signature patterns present in the piezophilic proteins. The experiments were performed on three different temperature ranges piezophilic groups, namely psychrophilic-piezophilic, mesophilic-piezophilic, and thermophilic-piezophilic for the detailed comparative study. The best classification results were obtained as we move up the temperature range from psychrophilic-piezophilic to thermophilic-piezophilic. Based on the physicochemical classification of amino acids and using feature ranking algorithms, hydrophilic and polar amino acid groups have higher discriminative ability for psychrophilic-piezophilic and mesophilic-piezophilic groups along with hydrophobic and nonpolar amino acids for the thermophilic-piezophilic groups. We also observed an overrepresentation of polar, hydrophilic and small amino acid groups in the discriminatory rules of all the three temperature range piezophiles along with aliphatic, nonpolar and hydrophobic groups in the mesophilic-piezophilic and thermophilic-piezophilic groups.
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Yang LL, Tang SK, Huang Y, Zhi XY. Low Temperature Adaptation Is Not the Opposite Process of High Temperature Adaptation in Terms of Changes in Amino Acid Composition. Genome Biol Evol 2015; 7:3426-33. [PMID: 26614525 PMCID: PMC4700962 DOI: 10.1093/gbe/evv232] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Previous studies focused on psychrophilic adaptation generally have demonstrated that multiple mechanisms work together to increase protein flexibility and activity, as well as to decrease the thermostability of proteins. However, the relationship between high and low temperature adaptations remains unclear. To investigate this issue, we collected the available predicted whole proteome sequences of species with different optimal growth temperatures, and analyzed amino acid variations and substitutional asymmetry in pairs of homologous proteins from related species. We found that changes in amino acid composition associated with low temperature adaptation did not exhibit a coherent opposite trend when compared with changes in amino acid composition associated with high temperature adaptation. This result indicates that during their evolutionary histories the proteome-scale evolutionary patterns associated with prokaryotes exposed to low temperature environments were distinct from the proteome-scale evolutionary patterns associated with prokaryotes exposed to high temperature environments in terms of changes in amino acid composition of the proteins.
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Affiliation(s)
- Ling-Ling Yang
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education and the Laboratory for Conservation and Utilization of Bio-Resources, Yunnan Institute of Microbiology, Yunnan University, Kunming, China
| | - Shu-Kun Tang
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education and the Laboratory for Conservation and Utilization of Bio-Resources, Yunnan Institute of Microbiology, Yunnan University, Kunming, China
| | - Ying Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiao-Yang Zhi
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education and the Laboratory for Conservation and Utilization of Bio-Resources, Yunnan Institute of Microbiology, Yunnan University, Kunming, China State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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Point Mutation Ile137-Met Near Surface Conferred Psychrophilic Behaviour and Improved Catalytic Efficiency to Bacillus Lipase of 1.4 Subfamily. Appl Biochem Biotechnol 2015; 178:753-65. [DOI: 10.1007/s12010-015-1907-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
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12
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Ding Y, Wang X, Mou Z. Communities in the iron superoxide dismutase amino acid network. J Theor Biol 2015; 367:278-285. [PMID: 25500180 DOI: 10.1016/j.jtbi.2014.11.030] [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: 05/06/2014] [Revised: 11/24/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
Abstract
Amino acid networks (AANs) analysis is a new way to reveal the relationship between protein structure and function. We constructed six different types of AANs based on iron superoxide dismutase (Fe-SOD) three-dimensional structure information. These Fe-SOD AANs have clear community structures when they were modularized by different methods. Especially, detected communities are related to Fe-SOD secondary structures. Regular structures show better correlations with detected communities than irregular structures, and loops weaken these correlations, which suggest that secondary structure is the unit element in Fe-SOD folding process. In addition, a comparative analysis of mesophilic and thermophilic Fe-SOD AANs' communities revealed that thermostable Fe-SOD AANs had more highly associated community structures than mesophilic one. Thermophilic Fe-SOD AANs also had more high similarity between communities and secondary structures than mesophilic Fe-SOD AANs. The communities in Fe-SOD AANs show that dense interactions in modules can help to stabilize thermophilic Fe-SOD.
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Affiliation(s)
- Yanrui Ding
- School of Digital Media, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China; Key Laboratory of Industrial Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China.
| | - Xueqin Wang
- School of Digital Media, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China
| | - Zhaolin Mou
- School of Digital Media, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China
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Nath A, Subbiah K. Inferring biological basis about psychrophilicity by interpreting the rules generated from the correctly classified input instances by a classifier. Comput Biol Chem 2014; 53PB:198-203. [PMID: 25462328 DOI: 10.1016/j.compbiolchem.2014.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/02/2014] [Accepted: 10/06/2014] [Indexed: 11/19/2022]
Abstract
Organisms thriving at extreme cold surroundings are called as psychrophiles and they present a wealth of knowledge about sequence adjustments in proteins that had occurred during the adaptation to low temperatures. In this paper, we propose a new cascading model to investigate the basis for psychrophilicity. In this model, a superior classifier was used to discriminate psychrophilic from mesophilic protein sequences, and then the PART rule generating algorithm was applied on the input instances that are correctly classified by the classifier, to generate human interpretable rules. These derived rules were further validated on a structural dataset and finally analyzed to discover the underlying biological basis about the psychrophilicity. In this study, we have used one of the key features of psychrophilic proteins accountable for remaining functional in extreme cold temperature surroundings i.e., global patterns of amino acid composition as the input features. The rotation forest classifier outperformed all the other classifiers with maximum accuracy of 70.5% and maximum AUC of 0.78. The effect of sequence length on the classification accuracy was also investigated. The analysis of the derived rules and interpretation of the analyzed results had revealed some interesting phenomena such as the amino acids A, D, G, F, and S are over-represented, and T is under-represented in psychrophilic proteins. These findings augment the existing domain knowledge for psychrophilic sequence features.
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Affiliation(s)
- Abhigyan Nath
- Bioinformatics Section, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi 221005, India.
| | - Karthikeyan Subbiah
- Department of Computer Science, Banaras Hindu University, Varanasi 221005, India.
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Identification and characterization of a cathepsin-L-like peptidase in Eimeria tenella. Parasitol Res 2014; 113:4335-48. [DOI: 10.1007/s00436-014-4107-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/26/2014] [Indexed: 11/26/2022]
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15
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The cold-adapted γ-glutamyl-cysteine ligase from the psychrophile Pseudoalteromonas haloplanktis. Biochimie 2014; 104:50-60. [DOI: 10.1016/j.biochi.2014.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/09/2014] [Indexed: 01/22/2023]
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16
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Merlino A, Russo Krauss I, Castellano I, Ruocco MR, Capasso A, De Vendittis E, Rossi B, Sica F. Structural and denaturation studies of two mutants of a cold adapted superoxide dismutase point to the importance of electrostatic interactions in protein stability. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:632-40. [DOI: 10.1016/j.bbapap.2014.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 10/25/2022]
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17
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Nonaka K, Yoon KS, Ogo S. Biochemical characterization of psychrophilic Mn-superoxide dismutase from newly isolated Exiguobacterium sp. OS-77. Extremophiles 2014; 18:363-73. [PMID: 24414928 DOI: 10.1007/s00792-013-0621-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 12/29/2013] [Indexed: 02/01/2023]
Abstract
Many types of superoxide dismutases have been purified and characterized from various bacteria, however, a psychrophilic Mn-superoxide dismutase (MnSOD) has not yet been reported. Here, we describe the purification and the biochemical characterization of the psychrophilic MnSOD from Exiguobacterium sp. strain OS-77 (EgMnSOD). According to 16S rRNA sequence analysis, a newly isolated bacterium strain OS-77 belongs to the genus Exiguobacterium. The optimum growth temperature of the strain OS-77 is 20 °C. The EgMnSOD is a homodimer of 23.5 kDa polypeptides determined by SDS-PAGE and gel filtration analysis. UV-Vis spectrum and ICP-MS analysis clearly indicated that the homogeneously purified enzyme contains only a Mn ion as a metal cofactor. The optimal reaction pH and temperature of the enzyme were pH 9.0 and 5 °C, respectively. Notably, the purified EgMnSOD was thermostable up to 45 °C and retained 50% activity after 21.2 min at 60 °C. The differential scanning calorimetry also indicated that the EgMnSOD is thermostable, exhibiting two protein denaturation peaks at 65 and 84 °C. The statistical analysis of amino acid sequence and composition of the EgMnSOD suggests that the enzyme retains psychrophilic characteristics.
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Affiliation(s)
- Kyoshiro Nonaka
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
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Yan Z, Nam YW, Fushinobu S, Wakagi T. Sulfolobus tokodaii ST2133 is characterized as a thioredoxin reductase-like ferredoxin:NADP+ oxidoreductase. Extremophiles 2013; 18:99-110. [DOI: 10.1007/s00792-013-0601-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 11/14/2013] [Indexed: 10/26/2022]
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Dassarma S, Capes MD, Karan R, Dassarma P. Amino acid substitutions in cold-adapted proteins from Halorubrum lacusprofundi, an extremely halophilic microbe from antarctica. PLoS One 2013; 8:e58587. [PMID: 23536799 PMCID: PMC3594186 DOI: 10.1371/journal.pone.0058587] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/05/2013] [Indexed: 11/18/2022] Open
Abstract
The halophilic Archaeon Halorubrum lacusprofundi, isolated from the perennially cold and hypersaline Deep Lake in Antarctica, was recently sequenced and compared to 12 Haloarchaea from temperate climates by comparative genomics. Amino acid substitutions for 604 H. lacusprofundi proteins belonging to conserved haloarchaeal orthologous groups (cHOGs) were determined and found to occur at 7.85% of positions invariant in proteins from mesophilic Haloarchaea. The following substitutions were observed most frequently: (a) glutamic acid with aspartic acid or alanine; (b) small polar residues with other small polar or non-polar amino acids; (c) small non-polar residues with other small non-polar residues; (d) aromatic residues, especially tryptophan, with other aromatic residues; and (e) some larger polar residues with other similar residues. Amino acid substitutions for a cold-active H. lacusprofundi β-galactosidase were then examined in the context of a homology modeled structure at residues invariant in homologous enzymes from mesophilic Haloarchaea. Similar substitutions were observed as in the genome-wide approach, with the surface accessible regions of β-galactosidase displaying reduced acidity and increased hydrophobicity, and internal regions displaying mainly subtle changes among smaller non-polar and polar residues. These findings are consistent with H. lacusprofundi proteins displaying amino acid substitutions that increase structural flexibility and protein function at low temperature. We discuss the likely mechanisms of protein adaptation to a cold, hypersaline environment on Earth, with possible relevance to life elsewhere.
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Affiliation(s)
- Shiladitya Dassarma
- Department of Microbiology and Immunology, and Institute of Marine and Environmental Technology, University of Maryland, Baltimore, Maryland, United States of America.
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Feller G. Psychrophilic enzymes: from folding to function and biotechnology. SCIENTIFICA 2013; 2013:512840. [PMID: 24278781 PMCID: PMC3820357 DOI: 10.1155/2013/512840] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 11/06/2012] [Indexed: 05/10/2023]
Abstract
Psychrophiles thriving permanently at near-zero temperatures synthesize cold-active enzymes to sustain their cell cycle. Genome sequences, proteomic, and transcriptomic studies suggest various adaptive features to maintain adequate translation and proper protein folding under cold conditions. Most psychrophilic enzymes optimize a high activity at low temperature at the expense of substrate affinity, therefore reducing the free energy barrier of the transition state. Furthermore, a weak temperature dependence of activity ensures moderate reduction of the catalytic activity in the cold. In these naturally evolved enzymes, the optimization to low temperature activity is reached via destabilization of the structures bearing the active site or by destabilization of the whole molecule. This involves a reduction in the number and strength of all types of weak interactions or the disappearance of stability factors, resulting in improved dynamics of active site residues in the cold. These enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate. Several open questions in the field are also highlighted.
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Affiliation(s)
- Georges Feller
- Laboratory of Biochemistry, Centre for Protein Engineering, Institute of Chemistry, University of Liège, B6a, 4000 Liège, Belgium
- *Georges Feller:
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Rajput R, Verma VV, Chaudhary V, Gupta R. A hydrolytic γ-glutamyl transpeptidase from thermo-acidophilic archaeon Picrophilus torridus: binding pocket mutagenesis and transpeptidation. Extremophiles 2012; 17:29-41. [PMID: 23104165 DOI: 10.1007/s00792-012-0490-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 10/09/2012] [Indexed: 11/26/2022]
Abstract
γ-Glutamyl transpeptidase of a thermo-acidophilic archaeon Picrophilus torridus was cloned and expressed using E. coli Rosetta-pET 51b(+) expression system. The enzyme was expressed at 37 °C/200 rpm with γ-GT production of 1.99 U/mg protein after 3 h of IPTG induction. It was improved nearby 10-fold corresponding to 18.92 U/mg protein in the presence of 2 % hexadecane. The enzyme was purified by Ni(2+)-NTA with a purification fold of 3.6 and recovery of 61 %. It was synthesized as a precursor heterodimeric protein of 47 kDa with two subunits of 30 kDa and 17 kDa, respectively, as revealed by SDS-PAGE and western blot. The enzyme possesses hydrolase activity with optima at pH 7.0 and 55 °C. It was thermostable with a t (1/2) of 1 h at 50 °C and 30 min at 60 °C, and retained 100 % activity at 45 °C even after 24 h. It was inhibited by azaserine and DON and PMSF. Ptγ-GT shared 37 % sequence identity and 53 % homology with an extremophile γ-GT from Thermoplasma acidophilum. Functional residues identified by in silico approaches were further validated by site-directed mutagenesis where Tyr327 mutated by Asn327 introduced significant transpeptidase activity.
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Affiliation(s)
- Rinky Rajput
- Department of Microbiology, University of Delhi, South Campus, New Delhi, 110021, India
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Optimization to low temperature activity in psychrophilic enzymes. Int J Mol Sci 2012; 13:11643-11665. [PMID: 23109875 PMCID: PMC3472767 DOI: 10.3390/ijms130911643] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/07/2012] [Accepted: 09/10/2012] [Indexed: 01/20/2023] Open
Abstract
Psychrophiles, i.e., organisms thriving permanently at near-zero temperatures, synthesize cold-active enzymes to sustain their cell cycle. These enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate. Most psychrophilic enzymes optimize a high activity at low temperature at the expense of substrate affinity, therefore reducing the free energy barrier of the transition state. Furthermore, a weak temperature dependence of activity ensures moderate reduction of the catalytic activity in the cold. In these naturally evolved enzymes, the optimization to low temperature activity is reached via destabilization of the structures bearing the active site or by destabilization of the whole molecule. This involves a reduction in the number and strength of all types of weak interactions or the disappearance of stability factors, resulting in improved dynamics of active site residues in the cold. Considering the subtle structural adjustments required for low temperature activity, directed evolution appears to be the most suitable methodology to engineer cold activity in biological catalysts.
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Kumari A, Verma VV, Gupta R. Comparative biochemical characterization and in silico analysis of novel lipases Lip11 and Lip12 with Lip2 from Yarrowia lipolytica. World J Microbiol Biotechnol 2012; 28:3103-11. [DOI: 10.1007/s11274-012-1120-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/26/2012] [Indexed: 11/28/2022]
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Joseph B, Shrivastava N, Ramteke PW. Extracellular cold-active lipase of Microbacterium luteolum isolated from Gangotri glacier, western Himalaya: Isolation, partial purification and characterization. JOURNAL OF GENETIC ENGINEERING AND BIOTECHNOLOGY 2012. [DOI: 10.1016/j.jgeb.2012.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Falasca P, Evangelista G, Cotugno R, Marco S, Masullo M, De Vendittis E, Raimo G. Properties of the endogenous components of the thioredoxin system in the psychrophilic eubacterium Pseudoalteromonas haloplanktis TAC 125. Extremophiles 2012; 16:539-52. [PMID: 22527046 DOI: 10.1007/s00792-012-0453-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 04/02/2012] [Indexed: 11/30/2022]
Abstract
The endogenous components of the thioredoxin system in the Antarctic eubacterium Pseudoalteromonas haloplanktis have been purified and characterised. The temperature dependence of the activities sustained by thioredoxin (PhTrx) and thioredoxin reductase (PhTrxR) pointed to their adaptation in the cold growth environment. PhTrxR was purified as a flavoenzyme and its activity was significantly enhanced in the presence of molar concentration of monovalent cations. The energetics of the partial reactions leading to the whole electron transfer from NADPH to the target protein substrate in the reconstituted thioredoxin system was also investigated. While the initial electron transfer from NADPH to PhTrxR was energetically favoured, the final passage to the heterologous protein substrate enhanced the energetic barrier of the whole process. The energy of activation of the heat inactivation process essentially reflected the psychrophilic origin of PhTrxR. Vice versa, PhTrx possessed an exceptional heat resistance (half-life, 4.4 h at 95 °C), ranking this protein among the most thermostable enzymes reported so far in psychrophiles. PhTrxR was covalently modified by glutathione, mainly by its oxidised or nitrosylated forms. A mutagenic analysis realised on three non catalytic cysteines of the flavoenzyme allowed the identification of C(303) as the target for the S-glutathionylation reaction.
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Affiliation(s)
- Patrizia Falasca
- Dipartimento di Scienze e Tecnologie dell'Ambiente e del Territorio, Università del Molise, Contrada Fonte Lappone, 86090, Pesche, IS, Italy
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Jollivet D, Mary J, Gagnière N, Tanguy A, Fontanillas E, Boutet I, Hourdez S, Segurens B, Weissenbach J, Poch O, Lecompte O. Proteome adaptation to high temperatures in the ectothermic hydrothermal vent Pompeii worm. PLoS One 2012; 7:e31150. [PMID: 22348046 PMCID: PMC3277501 DOI: 10.1371/journal.pone.0031150] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 01/03/2012] [Indexed: 12/19/2022] Open
Abstract
Taking advantage of the massive genome sequencing effort made on thermophilic prokaryotes, thermal adaptation has been extensively studied by analysing amino acid replacements and codon usage in these unicellular organisms. In most cases, adaptation to thermophily is associated with greater residue hydrophobicity and more charged residues. Both of these characteristics are positively correlated with the optimal growth temperature of prokaryotes. In contrast, little information has been collected on the molecular 'adaptive' strategy of thermophilic eukaryotes. The Pompeii worm A. pompejana, whose transcriptome has recently been sequenced, is currently considered as the most thermotolerant eukaryote on Earth, withstanding the greatest thermal and chemical ranges known. We investigated the amino-acid composition bias of ribosomal proteins in the Pompeii worm when compared to other lophotrochozoans and checked for putative adaptive changes during the course of evolution using codon-based Maximum likelihood analyses. We then provided a comparative analysis of codon usage and amino-acid replacements from a greater set of orthologous genes between the Pompeii worm and Paralvinella grasslei, one of its closest relatives living in a much cooler habitat. Analyses reveal that both species display the same high GC-biased codon usage and amino-acid patterns favoring both positively-charged residues and protein hydrophobicity. These patterns may be indicative of an ancestral adaptation to the deep sea and/or thermophily. In addition, the Pompeii worm displays a set of amino-acid change patterns that may explain its greater thermotolerance, with a significant increase in Tyr, Lys and Ala against Val, Met and Gly. Present results indicate that, together with a high content in charged residues, greater proportion of smaller aliphatic residues, and especially alanine, may be a different path for metazoans to face relatively 'high' temperatures and thus a novelty in thermophilic metazoans.
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Affiliation(s)
- Didier Jollivet
- Adaptation & Diversité en Milieu Marin, CNRS UMR 7144, Roscoff, France.
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Gao J, Wang W. Analysis of structural requirements for thermo-adaptation from orthologs in microbial genomes. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-012-0420-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Dick JM, Shock EL. Calculation of the relative chemical stabilities of proteins as a function of temperature and redox chemistry in a hot spring. PLoS One 2011; 6:e22782. [PMID: 21853048 PMCID: PMC3154912 DOI: 10.1371/journal.pone.0022782] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 06/29/2011] [Indexed: 11/23/2022] Open
Abstract
Uncovering the chemical and physical links between natural environments and microbial communities is becoming increasingly amenable owing to geochemical observations and metagenomic sequencing. At the hot spring known as Bison Pool in Yellowstone National Park, the cooling of the water in the outflow channel is associated with an increase in oxidation potential estimated from multiple field-based measurements. Representative groups of proteins whose sequences were derived from metagenomic data also exhibit an increase in average oxidation state of carbon in the protein molecules with distance from the hot-spring source. The energetic requirements of reactions to form selected proteins used in the model were computed using amino-acid group additivity for the standard molal thermodynamic properties of the proteins, and the relative chemical stabilities of the proteins were investigated by varying temperature, pH and oxidation state, expressed as activity of dissolved hydrogen. The relative stabilities of the proteins were found to track the locations of the sampling sites when the calculations included a function for hydrogen activity that increases with temperature and is higher, or more reducing, than values consistent with measurements of dissolved oxygen, sulfide and oxidation-reduction potential in the field. These findings imply that spatial patterns in the amino acid compositions of proteins can be linked, through energetics of overall chemical reactions representing the formation of the proteins, to the environmental conditions at this hot spring, even if microbial cells maintain considerably different internal conditions. Further applications of the thermodynamic calculations are possible for other natural microbial ecosystems.
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Affiliation(s)
- Jeffrey M Dick
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, United States of America.
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Gene cloning and protein expression of γ-glutamyltranspeptidases from Thermus thermophilus and Deinococcus radiodurans: comparison of molecular and structural properties with mesophilic counterparts. Extremophiles 2011; 15:259-70. [PMID: 21298394 DOI: 10.1007/s00792-011-0355-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
γ-Glutamyltranspeptidase (γ-GT) is an ubiquitous enzyme that catalyzes the hydrolysis of γ-glutamyl bonds in glutathione and glutamine and the transfer of the released γ-glutamyl group to amino acids or short peptides. γ-GTs from extremophiles, bacteria adapted to live in hostile environments, were selected as model systems to study the molecular underpinnings of their adaptation to extreme conditions and to find out special properties of potential biotechnological interest. Here, we report the cloning, expression and purification of two members of γ-GT family from two different extremophilic species, Thermus thermophilus (TtGT) and Deinococcus radiodurans (DrGT); the first is an aerobic eubacterium, growing at high temperatures (50-82°C), the second is a polyextremophile, as it tolerates radiations, cold, dehydration, vacuum, and acid. TtGT and DrGT were both synthesized as precursor proteins of 59-60 kDa, undergoing an intramolecular auto-cleavage to yield two subunits of 40 and 19-20 kDa, respectively. However, like the γ-GT from Geobacillus thermodenitrificans, but differently from the other characterized bacterial and eukaryotic γ-GTs, the two new extremophilic enzymes displayed γ-glutamyl hydrolase, but not transpeptidase activity in the 37-50°C temperature range, pH 8.0. The comparison of sequences and structural models of these two proteins with experimental-determined structures of other known mesophilic γ-GTs suggests that the extremophilic members of this protein family have found a common strategy to adapt to different hostile environments. Moreover, a phylogenetic analysis suggests that γ-GTs displaying only γ-glutamyl hydrolase activity could represent the progenitors of the bacterial and eukaryotic counterparts.
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Amino acid composition in endothermic vertebrates is biased in the same direction as in thermophilic prokaryotes. BMC Evol Biol 2010; 10:263. [PMID: 20807394 PMCID: PMC2939578 DOI: 10.1186/1471-2148-10-263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 08/31/2010] [Indexed: 11/18/2022] Open
Abstract
Background Among bacteria and archaea, amino acid usage is correlated with habitat temperatures. In particular, protein surfaces in species thriving at higher temperatures appear to be enriched in amino acids that stabilize protein structure and depleted in amino acids that decrease thermostability. Does this observation reflect a causal relationship, or could the apparent trend be caused by phylogenetic relatedness among sampled organisms living at different temperatures? And do proteins from endothermic and exothermic vertebrates show similar differences? Results We find that the observed correlations between the frequencies of individual amino acids and prokaryotic habitat temperature are strongly influenced by evolutionary relatedness between the species analysed; however, a proteome-wide bias towards increased thermostability remains after controlling for phylogeny. Do eukaryotes show similar effects of thermal adaptation? A small shift of amino acid usage in the expected direction is observed in endothermic ('warm-blooded') mammals and chicken compared to ectothermic ('cold-blooded') vertebrates with lower body temperatures; this shift is not simply explained by nucleotide usage biases. Conclusion Protein homologs operating at different temperatures have different amino acid composition, both in prokaryotes and in vertebrates. Thus, during the transition from ectothermic to endothermic life styles, the ancestors of mammals and of birds may have experienced weak genome-wide positive selection to increase the thermostability of their proteins.
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Merlino A, Russo Krauss I, Castellano I, De Vendittis E, Rossi B, Conte M, Vergara A, Sica F. Structure and flexibility in cold-adapted iron superoxide dismutases: the case of the enzyme isolated from Pseudoalteromonas haloplanktis. J Struct Biol 2010; 172:343-52. [PMID: 20732427 DOI: 10.1016/j.jsb.2010.08.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/29/2010] [Accepted: 08/18/2010] [Indexed: 10/19/2022]
Abstract
Superoxide dismutases (SODs) are metalloenzymes catalysing the dismutation of superoxide anion radicals into molecular oxygen and hydrogen peroxide. Here, we present the crystal structure of a cold-adapted Fe-SOD from the Antarctic eubacterium Pseudoalteromonas haloplanktis (PhSOD), and that of its complex with sodium azide. The structures were compared with those of the corresponding homologues having a high sequence identity with PhSOD, such as the mesophilic SOD from Escherichia coli (EcSOD) or Pseudomonas ovalis, and the psychrophilic SOD from Aliivibrio salmonicida (AsSOD). These enzymes shared a large structural similarity, such as a conserved tertiary structure and arrangement of the two monomers, an almost identical total number of inter- and intramolecular hydrogen bonds and salt bridges. However, the two cold-adapted SODs showed an increased flexibility of the active site residues with respect to their mesophilic homologues. Structural information was combined with a characterisation of the chemical and thermal stability performed by CD and fluorescence measurements. Despite of its psychrophilic origin, the denaturation temperature of PhSOD was comparable with that of the mesophilic EcSOD, whereas AsSOD showed a lower denaturation temperature. On the contrary, the values of the denaturant concentration at the transition midpoint were in line with the psychrophilic/mesophilic origin of the proteins. These data provide additional support to the hypothesis that cold-adapted enzymes achieve efficient catalysis at low temperature, by increasing the flexibility of their active site; moreover, our results underline how fine structural modifications can alter enzyme flexibility and/or stability without compromising the overall structure of typical rigid enzymes, such as SODs.
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Affiliation(s)
- Antonello Merlino
- Dipartimento di Chimica, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy
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Biochemical and structural properties of gamma-glutamyl transpeptidase from Geobacillus thermodenitrificans: an enzyme specialized in hydrolase activity. Biochimie 2010; 92:464-74. [PMID: 20138205 DOI: 10.1016/j.biochi.2010.01.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Accepted: 01/26/2010] [Indexed: 12/29/2022]
Abstract
Gamma-glutamyltranspeptidases (gamma-GTs) catalyze the transfer of the gamma-glutamyl moiety of glutathione and related gamma-glutamyl amides to water (hydrolysis) or to amino acids and peptides (transpeptidation) and play a key role in glutathione metabolism. Recently, gamma-GTs have been considered attractive pharmaceutical targets for cancer and useful tools to produce gamma-glutamyl compounds. To find out gamma-GTs with special properties we have chosen microorganisms belonging to Geobacillus species which are source of several thermostable enzymes of potential interest for biotechnology. gamma-GT from Geobacillus thermodenitrificans (GthGT) was cloned, expressed in Escherichia coli, purified to homogeneity and characterized. The enzyme, synthesized as a precursor homotetrameric protein of 61-kDa per subunit, undergoes an internal post-translational cleavage of the 61 kDa monomer into 40- and 21-kDa shorter subunits, which are then assembled into an active heterotetramer composed of two 40- and two 21-kDa subunits. The kinetic characterization of the hydrolysis reaction using L-glutamic acid gamma-(4-nitroanilide) as the substrate reveals that the active enzyme has K(m) 7.6 microM and V(max) 0.36 micromol min/mg. The optimum pH and temperature for the hydrolysis activity are 7.8 and 52 degrees C, respectively. GthGT hydrolyses the physiological antioxidant glutathione, suggesting an involvement of the enzyme in the cellular defense mechanism against oxidative stress. Unlike other gamma-GTs, the mutation of the highly conserved catalytic nucleophile, Thr353, abolishes the post-translational cleavage of the pro-enzyme, but does not completely block the hydrolytic action. Furthermore, GthGT does not show any transpeptidase activity, suggesting that the enzyme is a specialized gamma-glutamyl hydrolase. The GthGT homology-model structure reveals peculiar structural features, which should be responsible for the different functional properties of the enzyme and suggests the structural bases of protein thermostability.
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Metpally RPR, Reddy BVB. Comparative proteome analysis of psychrophilic versus mesophilic bacterial species: Insights into the molecular basis of cold adaptation of proteins. BMC Genomics 2009; 10:11. [PMID: 19133128 PMCID: PMC2653534 DOI: 10.1186/1471-2164-10-11] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 01/08/2009] [Indexed: 11/10/2022] Open
Abstract
Background Cold adapted or psychrophilic organisms grow at low temperatures, where most of other organisms cannot grow. This adaptation requires a vast array of sequence, structural and physiological adjustments. To understand the molecular basis of cold adaptation of proteins, we analyzed proteomes of psychrophilic and mesophilic bacterial species and compared the differences in amino acid composition and substitution patterns to investigate their likely association with growth temperatures. Results In psychrophilic bacteria, serine, aspartic acid, threonine and alanine are overrepresented in the coil regions of secondary structures, whilst glutamic acid and leucine are underrepresented in the helical regions. Compared to mesophiles, psychrophiles comprise a significantly higher proportion of amino acids that contribute to higher protein flexibility in the coil regions of proteins, such as those with tiny/small or neutral side chains. Amino acids with aliphatic, basic, aromatic and hydrophilic side chains are underrepresented in the helical regions of proteins of psychrophiles. The patterns of amino acid substitutions between the orthologous proteins of psychrophiles versus mesophiles are significantly different for several amino acids when compared to their substitutions in orthologous proteins of within the mesophiles or psychrophiles. Conclusion Current results provide quantitative substitution preferences (or avoidance) of amino acids that lead to the adaptation of proteins to cold temperatures. These finding would help future efforts in selecting mutations for rational design of proteins with enhanced psychrophilic properties.
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Affiliation(s)
- Raghu Prasad Rao Metpally
- Laboratory of Bioinformatics and in Silico Drug Design, Computer Science Department, Queens College of City University of New York, 65-30 Kissena Blvd,, Flushing, NY 11367, USA.
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Cold stability of intrinsically disordered proteins. FEBS Lett 2008; 583:465-9. [PMID: 19121309 DOI: 10.1016/j.febslet.2008.12.054] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 01/27/2023]
Abstract
Contrary to globular proteins, intrinsically disordered proteins (IDPs) lack a folded structure and they do not lose solubility at elevated temperatures. Although this should also be true at low temperatures, cold stability of IDPs has not been addressed in any scientific work so far. As direct characterization of cold-denaturation is difficult, we approached the problem through a freezing-induced loss-of-function model of globular-disordered functional protein pairs (m-calpain-calpastatin, tubulin-Map2c, Hsp90-ERD14). Our results affirm that in contrast with globular proteins IDPs are resistant to cold treatment. The theoretical and functional aspects of this observation are discussed.
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