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Characterization of M116.1p, a murine cytomegalovirus protein required for efficient infection of mononuclear phagocytes. J Virol 2021; 96:e0087621. [PMID: 34705561 DOI: 10.1128/jvi.00876-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Broad tissue tropism of cytomegaloviruses (CMVs) is facilitated by different glycoprotein entry complexes, which are conserved between human CMV (HCMV) and murine CMV (MCMV). Among the wide array of cell types susceptible to the infection, mononuclear phagocytes (MNPs) play a unique role in the pathogenesis of the infection as they contribute both to the virus spread and immune control. CMVs have dedicated numerous genes for the efficient infection and evasion of macrophages and dendritic cells. In this study, we have characterized the properties and function of M116, a previously poorly described but highly transcribed MCMV gene region which encodes M116.1p, a novel protein necessary for the efficient infection of MNPs and viral spread in vivo. Our study further revealed that M116.1p shares similarities with its positional homologs in HCMV and RCMV, UL116 and R116, respectively, such as late kinetics of expression, N-glycosylation, localization to the virion assembly compartment, and interaction with gH - a member of the CMVs fusion complex. This study, therefore, expands our knowledge about virally encoded glycoproteins that play important roles in viral infectivity and tropism. Importance Human cytomegalovirus (HCMV) is a species-specific herpesvirus that causes severe disease in immunocompromised individuals and immunologically immature neonates. Murine cytomegalovirus (MCMV) is biologically similar to HCMV, and it serves as a widely used model for studying the infection, pathogenesis, and immune responses to HCMV. In our previous work, we have identified the M116 ORF as one of the most extensively transcribed regions of the MCMV genome without an assigned function. This study shows that the M116 locus codes for a novel protein, M116.1p, which shares similarities with UL116 and R116 in HCMV and RCMV, respectively, and is required for the efficient infection of mononuclear phagocytes and virus spread in vivo. Furthermore, this study establishes the α-M116 monoclonal antibody and MCMV mutants lacking M116, generated in this work, as valuable tools for studying the role of macrophages and dendritic cells in limiting CMV infection following different MCMV administration routes.
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Biochemical characteristics of the chondrocyte-enriched SNORC protein and its transcriptional regulation by SOX9. Sci Rep 2020; 10:7790. [PMID: 32385306 PMCID: PMC7210984 DOI: 10.1038/s41598-020-64640-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/16/2020] [Indexed: 11/08/2022] Open
Abstract
Snorc (Small NOvel Rich in Cartilage) has been identified as a chondrocyte-specific gene in the mouse. Yet little is known about the SNORC protein biochemical properties, and mechanistically how the gene is regulated transcriptionally in a tissue-specific manner. The goals of the present study were to shed light on those important aspects. The chondrocyte nature of Snorc expression was confirmed in mouse and rat tissues, in differentiated (day 7) ATDC5, and in RCS cells where it was constitutive. Topological mapping and biochemical analysis brought experimental evidences that SNORC is a type I protein carrying a chondroitin sulfate (CS) attached to serine 44. The anomalous migration of SNORC on SDS-PAGE was due to its primary polypeptide features, suggesting no additional post-translational modifications apart from the CS glycosaminoglycan. A highly conserved SOX9-binding enhancer located in intron 1 was necessary to drive transcription of Snorc in the mouse, rat, and human. The enhancer was active independently of orientation and whether located in a heterologous promoter or intron. Crispr-mediated inactivation of the enhancer in RCS cells caused reduction of Snorc. Transgenic mice carrying the intronic multimerized enhancer drove high expression of a βGeo reporter in chondrocytes, but not in the hypertrophic zone. Altogether these data confirmed the chondrocyte-specific nature of Snorc and revealed dependency on the intronic enhancer binding of SOX9 for transcription.
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Pestov NB, Kalinovsky DV, Larionova TD, Zakirova AZ, Modyanov NN, Okkelman IA, Korneenko TV. Properties of a cryptic lysyl oxidase from haloarchaeon Haloterrigena turkmenica. PeerJ 2019; 7:e6691. [PMID: 30984480 PMCID: PMC6452851 DOI: 10.7717/peerj.6691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/26/2019] [Indexed: 11/20/2022] Open
Abstract
Background Lysyl oxidases (LOX) have been extensively studied in mammals, whereas properties and functions of recently found homologues in prokaryotic genomes remain enigmatic. Methods LOX open reading frame was cloned from Haloterrigena turkmenica in an E. coli expression vector. Recombinant Haloterrigena turkmenica lysyl oxidase (HTU-LOX) proteins were purified using metal affinity chromatography under denaturing conditions followed by refolding. Amine oxidase activity has been measured fluorometrically as hydrogen peroxide release coupled with the oxidation of 10-acetyl-3,7-dihydroxyphenoxazine in the presence of horseradish peroxidase. Rabbit polyclonal antibodies were obtained and used in western blotting. Results Cultured H. turkmenica has no detectable amine oxidase activity. HTU-LOX may be expressed in E. coli with a high protein yield. The full-length protein gives no catalytic activity. For this reason, we hypothesized that the hydrophobic N-terminal region may interfere with proper folding and its removal may be beneficial. Indeed, truncated His-tagged HTU-LOX lacking the N-terminal hydrophobic signal peptide purified under denaturing conditions can be successfully refolded into an active enzyme, and a larger N-terminal truncation further increases the amine oxidase activity. Refolding is optimal in the presence of Cu2+ at pH 6.2 and is not sensitive to salt. HTU-LOX is sensitive to LOX inhibitor 3-aminopropionitrile. HTU-LOX deaminates usual substrates of mammalian LOX such as lysine-containing polypeptides and polymers. The major difference between HTU-LOX and mammalian LOX is a relaxed substrate specificity of the former. HTU-LOX readily oxidizes various primary amines including such compounds as taurine and glycine, benzylamine being a poor substrate. Of note, HTU-LOX is also active towards several aminoglycoside antibiotics and polymyxin. Western blotting indicates that epitopes for the anti-HTU-LOX polyclonal antibodies coincide with a high molecular weight protein in H. turkmenica cells. Conclusion H. turkmenica contains a lysyl oxidase gene that was heterologously expressed yielding an active recombinant enzyme with important biochemical features conserved between all known LOXes, for example, the sensitivity to 3-aminopropionitrile. However, the native function in the host appears to be cryptic. Significance This is the first report on some properties of a lysyl oxidase from Archaea and an interesting example of evolution of enzymatic properties after hypothetical horizontal transfers between distant taxa.
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Affiliation(s)
- Nikolay B Pestov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | | | | | - Alia Z Zakirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Nikolai N Modyanov
- Department of Physiology and Pharmacology, University of Toledo, Toledo, OH, United States of America
| | - Irina A Okkelman
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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Tiwari P, Kaila P, Guptasarma P. Understanding anomalous mobility of proteins on SDS‐PAGE with special reference to the highly acidic extracellular domains of human E‐ and N‐cadherins. Electrophoresis 2019; 40:1273-1281. [DOI: 10.1002/elps.201800219] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 12/21/2018] [Accepted: 01/14/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Prince Tiwari
- Centre for Protein ScienceDesign and EngineeringDepartment of Biological SciencesIndian Institute of Science Education and Research (IISER) Mohali Punjab India
| | - Pallavi Kaila
- Centre for Protein ScienceDesign and EngineeringDepartment of Biological SciencesIndian Institute of Science Education and Research (IISER) Mohali Punjab India
| | - Purnananda Guptasarma
- Centre for Protein ScienceDesign and EngineeringDepartment of Biological SciencesIndian Institute of Science Education and Research (IISER) Mohali Punjab India
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Bogen O, Bender O, Alvarez P, Kern M, Tomiuk S, Hucho F, Levine JD. Expression of a novel versican variant in dorsal root ganglia from spared nerve injury rats. Mol Pain 2019; 15:1744806919874557. [PMID: 31429356 PMCID: PMC6724496 DOI: 10.1177/1744806919874557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The size and modular structure of versican and its gene suggest the existence of multiple splice variants. We have identified, cloned, and sequenced a previously unknown exon located within the noncoding gene sequence downstream of exon 8. This exon, which we have named exon 8β, specifies two stop-codons. mRNAs of the versican gene with exon 8β are predicted to be constitutively degraded by nonsense-mediated RNA decay. Here, we tested the hypothesis that these transcripts become expressed in a model of neuropathic pain.
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Affiliation(s)
- Oliver Bogen
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Olaf Bender
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Pedro Alvarez
- Department of Oral & Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Marie Kern
- Department of Oral & Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
| | | | - Ferdinand Hucho
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Jon D Levine
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
- Department of Oral & Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
- Jon D Levine, University of California San Francisco Medical Center at Parnassus, 533 Parnassu Ave, San Francisco, San Francisco, CA 94143, USA.
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Characterization of a novel cysteine-rich antifungal protein from Fusarium graminearum with activity against maize fungal pathogens. Int J Food Microbiol 2018; 283:45-51. [DOI: 10.1016/j.ijfoodmicro.2018.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 02/08/2023]
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Bírová S, Levarski Z, Vidličková I, Pastoreková S, Turňa J, Stuchlík S. Purification of small-size acidic proteoglycan-like domain of carbonic anhydrase IX fused with thioredoxine expressed in Escherichia coli for structural characterization. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Olombrada M, García-Ortega L, Lacadena J, Oñaderra M, Gavilanes JG, Martínez-del-Pozo Á. Involvement of loop 5 lysine residues and the N-terminal β-hairpin of the ribotoxin hirsutellin A on its insecticidal activity. Biol Chem 2016; 397:135-45. [DOI: 10.1515/hsz-2015-0261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/17/2015] [Indexed: 11/15/2022]
Abstract
Abstract
Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger, with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties. Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently, four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity, being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.
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Singh PK, Ratnam N, Narayanarao KB, Bugatha H, Karande AA, Melkote Subbarao S. A carboxy terminal domain of the L protein of rinderpest virus possesses RNA triphosphatase activity - The first enzyme in the viral mRNA capping pathway. Biochem Biophys Res Commun 2015; 464:629-34. [PMID: 26168720 DOI: 10.1016/j.bbrc.2015.07.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/06/2015] [Indexed: 11/30/2022]
Abstract
The large protein L of negative-sense RNA viruses is a multifunctional protein involved in transcription and replication of genomic RNA. It also possesses enzymatic activities involved in capping and methylation of viral mRNAs. The pathway for mRNA capping followed by the L protein of the viruses in the Morbillivirus genus has not been established, although it has been speculated that these viruses may follow the unconventional capping pathway as has been shown for some viruses of Rhabdoviridae family. We had earlier shown that the large protein L of Rinderpest virus expressed as recombinant L-P complex in insect cells as well as the ribonucleoprotein complex from purified virus possesses RNA triphosphatase (RTPase) and guanylyltransferase activities, in addition to RNA dependent RNA polymerase activity. In the present work, we demonstrate that RTPase as well as nucleoside triphosphatase (NTPase) activities are exhibited by a subdomain of the L protein in the C terminal region (a.a. 1640-1840). The RTPase activity depends absolutely on a divalent cation, either magnesium or manganese. Both the RTPase and NTPase activities of the protein show dual metal specificity. Two mutant proteins having alanine mutations in the glutamic acid residues in motif-A of the RTPase domain did not show RTPase activity, while exhibiting reduced NTPase activity suggesting overlapping active sites for the two enzymatic functions. The RTPase and NTPase activities of the L subdomain resemble those of the Vaccinia capping enzyme D1 and the baculovirus LEF4 proteins.
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Affiliation(s)
- Piyush Kumar Singh
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Nivedita Ratnam
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Kannan Boosi Narayanarao
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Harigopalarao Bugatha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Anjali A Karande
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Shaila Melkote Subbarao
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
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Houser WM, Butterer A, Addepalli B, Limbach PA. Combining recombinant ribonuclease U2 and protein phosphatase for RNA modification mapping by liquid chromatography–mass spectrometry. Anal Biochem 2015; 478:52-8. [DOI: 10.1016/j.ab.2015.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 02/21/2015] [Accepted: 03/12/2015] [Indexed: 10/23/2022]
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Conde JA, Claunch CJ, Romo HE, Benito-Martín A, Ballestero RP, González-García M. Identification of a motif in BMRP required for interaction with Bcl-2 by site-directed mutagenesis studies. J Cell Biochem 2013; 113:3498-508. [PMID: 22711503 DOI: 10.1002/jcb.24226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Bcl-2 is an anti-apoptotic protein that inhibits apoptosis elicited by multiple stimuli in a large variety of cell types. BMRP (also known as MRPL41) was identified as a Bcl-2 binding protein and shown to promote apoptosis. Previous studies indicated that the amino-terminal two-thirds of BMRP contain the domain(s) required for its interaction with Bcl-2, and that this region of the protein is responsible for the majority of the apoptosis-inducing activity of BMRP. We have performed site-directed mutagenesis analyses to further characterize the BMRP/Bcl-2 interaction and the pro-apoptotic activity of BMRP. The results obtained indicate that the 13-17 amino acid region of BMRP is necessary for its binding to Bcl-2. Further mutagenesis of this motif shows that amino acid residue aspartic acid (D) 16 of BMRP is essential for the BMRP/Bcl-2 interaction. Functional analyses conducted in mammalian cells with BMRP site-directed mutants BMRP(13Ala17) and BMRP(D16A) indicate that these mutants induce apoptosis through a caspase-mediated pathway, and that they kill cells slightly more potently than wild-type BMRP. Bcl-2 is still able to counteract BMRP(D16A)-induced cell death significantly, but not as completely as when tested against wild-type BMRP. These results suggest that the apoptosis-inducing ability of wild-type BMRP is blocked by Bcl-2 through several mechanisms.
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Affiliation(s)
- Juan A Conde
- Department of Chemistry, Texas A&M University-Kingsville, Kingsville, Texas 78363, USA
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Karan R, Capes MD, DasSarma P, DasSarma S. Cloning, overexpression, purification, and characterization of a polyextremophilic β-galactosidase from the Antarctic haloarchaeon Halorubrum lacusprofundi. BMC Biotechnol 2013; 13:3. [PMID: 23320757 PMCID: PMC3556326 DOI: 10.1186/1472-6750-13-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/14/2013] [Indexed: 01/18/2023] Open
Abstract
Background Halorubrum lacusprofundi is a cold-adapted halophilic archaeon isolated from Deep Lake, a perennially cold and hypersaline lake in Antarctica. Its genome sequencing project was recently completed, providing access to many genes predicted to encode polyextremophilic enzymes active in both extremely high salinity and cold temperatures. Results Analysis of the genome sequence of H. lacusprofundi showed a gene cluster for carbohydrate utilization containing a glycoside hydrolase family 42 β-galactosidase gene, named bga. In order to study the biochemical properties of the β-galactosidase enzyme, the bga gene was PCR amplified, cloned, and expressed in the genetically tractable haloarchaeon Halobacterium sp. NRC-1 under the control of a cold shock protein (cspD2) gene promoter. The recombinant β-galactosidase protein was produced at 20-fold higher levels compared to H. lacusprofundi, purified using gel filtration and hydrophobic interaction chromatography, and identified by SDS-PAGE, LC-MS/MS, and ONPG hydrolysis activity. The purified enzyme was found to be active over a wide temperature range (−5 to 60°C) with an optimum of 50°C, and 10% of its maximum activity at 4°C. The enzyme also exhibited extremely halophilic character, with maximal activity in either 4 M NaCl or KCl. The polyextremophilic β-galactosidase was also stable and active in 10–20% alcohol-aqueous solutions, containing methanol, ethanol, n-butanol, or isoamyl alcohol. Conclusion The H. lacusprofundi β-galactosidase is a polyextremophilic enzyme active in high salt concentrations and low and high temperature. The enzyme is also active in aqueous-organic mixed solvents, with potential applications in synthetic chemistry. H. lacuprofundi proteins represent a significant biotechnology resource and for developing insights into enzyme catalysis under water limiting conditions. This study provides a system for better understanding how H. lacusprofundi is successful in a perennially cold, hypersaline environment, with relevance to astrobiology.
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Affiliation(s)
- Ram Karan
- Department of Microbiology and Immunology, University of Maryland School of Medicine, and Institute of Marine and Environmental Technology, University System of Maryland, 701 E Pratt Street, Baltimore, MD 21202, USA
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Guan G, Moreau E, Liu J, Ma M, Rogniaux H, Liu A, Niu Q, Li Y, Ren Q, Luo J, Chauvin A, Yin H. BQP35 is a novel member of the intrinsically unstructured protein (IUP) family which is a potential antigen for the sero-diagnosis of Babesia sp. BQ1 (Lintan) infection. Vet Parasitol 2012; 187:421-30. [PMID: 22317784 DOI: 10.1016/j.vetpar.2012.01.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 01/04/2012] [Accepted: 01/13/2012] [Indexed: 11/19/2022]
Abstract
A new gene of Babesia sp. BQ1 (Lintan) (BQP35) was cloned by screening a merozoite cDNA expression library with infected sheep serum and using rapid amplification of cDNA ends (RACE). The nucleotide sequence of the cDNA was 1140bp with an open reading frame (ORF) of 936bp encoding a 35-kDa predicted polypeptide with 311 amino acid residues. Comparison of BQP35 cDNA and genomic DNA sequences showed that BQP35 does not possess an intron. Recombinant BQP35 (rBQP35), expressed in a prokaryotic expression system, showed abnormally slow migration on SDS-PAGE. Gel shifting, amino acid sequence and in silico disorder region prediction indicated that BQP35 protein has characteristics of intrinsically unstructured proteins (IUPs). This is the first description of such proteins in the Babesia genus. BQP35 induced antibodies production as early as one week after Babesia sp. BQ1 (Lintan) infection in sheep. No cross-reaction was observed with sera from sheep infected with other ovine piroplasms dominant in China, except with Babesia sp. Tianzhu. The interest of BQP35 as a diagnostic antigen is discussed.
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Affiliation(s)
- Guiquan Guan
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu 730046, PR China
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Fattahian Y, Rasooli I, Mousavi Gargari SL, Rahbar MR, Darvish Alipour Astaneh S, Amani J. Protection against Acinetobacter baumannii infection via its functional deprivation of biofilm associated protein (Bap). Microb Pathog 2011; 51:402-6. [PMID: 21946278 DOI: 10.1016/j.micpath.2011.09.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 09/07/2011] [Accepted: 09/15/2011] [Indexed: 02/06/2023]
Abstract
Acinetobacter baumannii, a major nosocomial pathogen, has remarkable capacity to acquire antimicrobial resistance attributable to its biofilm formation ability. Biofilm associated protein (Bap), a specific cell surface protein, is directly involved in biofilm formation by A. baumannii and plays a major role in bacterial infectious processes. In the present study we cloned, expressed and purified a 371 amino acid subunit of Bap. Mice were immunized using recombinant Bap subunit. They were then challenged with A. baumannii to evaluate the immunogenicity and protectivity of Bap subunit. Humoral immune response to Bap was determined by ELISA. Injection of Bap subunit resulted in high antibody titers. Decrease in bacterial cell counts of the immunized mice was evident 18 h after challenge. Reaction of antibodies against Bap with several strains suggests that not only immunodominant regions of Bap in A. baumannii strains are conserved but also have the same epitope presenting pattern in different strains. Immunodominant region of Bap possesses target sites for a protective humoral immune response to A. baumannii. This seems to be a conserved region erecting efficacy of Bap as an appropriate vaccine candidate.
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Affiliation(s)
- Yaser Fattahian
- Department of Biology, Shahed University, Tehran-Qom Express Way, Opposite Imam Khomeini's shrine, Tehran-3319118651, Iran
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Lee A, Tang SKY, Mace CR, Whitesides GM. Denaturation of proteins by SDS and tetraalkylammonium dodecyl sulfates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:11560-74. [PMID: 21834533 PMCID: PMC3172379 DOI: 10.1021/la201832d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This article describes the use of capillary electrophoresis (CE) to examine the influence of different cations (C(+); C(+) = Na(+) and tetra-n-alkylammonium, NR(4)(+), where R = Me, Et, Pr, and Bu) on the rates of denaturation of bovine carbonic anhydrase II (BCA) in the presence of anionic surfactant dodecylsulfate (DS(-)). An analysis of the denaturation of BCA in solutions of Na(+)DS(-) and NR(4)(+)DS(-) (in Tris-Gly buffer) indicated that the rates of formation of complexes of denatured BCA with DS(-) (BCA(D)-DS(-)(n,sat)) are indistinguishable and independent of the cation below the critical micellar concentration (cmc) and independent of the total concentration of DS(-) above the cmc. At concentrations of C(+)DS(-) above the cmc, BCA denatured at rates that depended on the cation; the rates decreased by a factor >10(4) in the order of Na(+) ≈ NMe(4)(+) > NEt(4)(+) > NPr(4)(+) > NBu(4)(+), which is the same order as the values of the cmc (which decrease from 4.0 mM for Na(+)DS(-) to 0.9 mM for NBu(4)(+)DS(-) in Tris-Gly buffer). The relationship between the cmc values and the rates of formation of BCA(D)-DS(-)(n,sat()) suggested that the kinetics of denaturation of BCA involve the association of this protein with monomeric DS(-) rather than with micelles of (C(+)DS(-))(n). A less-detailed survey of seven other proteins (α-lactalbumin, β-lactoglobulin A, β-lactoglobulin B, carboxypeptidase B, creatine phosphokinase, myoglobin, and ubiquitin) showed that the difference between Na(+)DS(-) and NR(4)(+)DS(-) observed with BCA was not general. Instead, the influence of NR(4)(+) on the association of DS(-) with these proteins depended on the protein. The selection of the cation contributed to the properties (including the composition, electrophoretic mobility, and partitioning behavior in aqueous two-phase systems) of aggregates of denatured protein and DS(-). These results suggest that the variation in the behavior of NR(4)(+)DS(-) with changes in R may be exploited in methods used to analyze and separate mixtures of proteins.
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Affiliation(s)
- Andrew Lee
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts, USA
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Peterson AW, Pendrak ML, Roberts DD. ATP binding to hemoglobin response gene 1 protein is necessary for regulation of the mating type locus in Candida albicans. J Biol Chem 2011; 286:13914-24. [PMID: 21372131 PMCID: PMC3077592 DOI: 10.1074/jbc.m110.180190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 02/28/2011] [Indexed: 11/06/2022] Open
Abstract
HBR1 (hemoglobin response gene 1) is an essential gene in Candida albicans that positively regulates mating type locus MTLα gene expression and thereby regulates cell type-specific developmental genes. Hbr1p contains a phosphate-binding loop (P-loop), a highly conserved motif characteristic of ATP- and GTP-binding proteins. Recombinant Hbr1p was isolated in an oligomeric state that specifically bound ATP with K(d) ∼2 μM. ATP but not ADP, AMP, GTP, or dATP specifically protected Hbr1p from proteolysis by trypsin. Site-directed mutagenesis of the highly conserved P-loop lysine (K22Q) and the less conserved glycine (G19S) decreased the binding affinity for soluble ATP and ATP immobilized through its γ-phosphate. ATP bound somewhat more avidly than ATPγS to wild type and mutant Hbr1p. Although Hbr1p exhibits sequence motifs characteristic of adenylate kinases, and adenylate kinase and ATPase activities have been reported for the apparent human ortholog of Hbr1p, assays for adenylate kinase activity, autophosphorylation, and ATPase activity proved negative. Overexpression of wild type but not the mutant forms of Hbr1p restored MTlα2 expression in an HBR1/hbr1 mutant, indicating that ATP binding to the P-loop is necessary for this function of Hbr1p.
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Affiliation(s)
- Alexander W. Peterson
- From the Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1500
| | - Michael L. Pendrak
- From the Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1500
| | - David D. Roberts
- From the Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1500
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Franken B, Eggert T, Jaeger KE, Pohl M. Mechanism of acetaldehyde-induced deactivation of microbial lipases. BMC BIOCHEMISTRY 2011; 12:10. [PMID: 21342514 PMCID: PMC3049140 DOI: 10.1186/1471-2091-12-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 02/22/2011] [Indexed: 11/23/2022]
Abstract
Background Microbial lipases represent the most important class of biocatalysts used for a wealth of applications in organic synthesis. An often applied reaction is the lipase-catalyzed transesterification of vinyl esters and alcohols resulting in the formation of acetaldehyde which is known to deactivate microbial lipases, presumably by structural changes caused by initial Schiff-base formation at solvent accessible lysine residues. Previous studies showed that several lipases were sensitive toward acetaldehyde deactivation whereas others were insensitive; however, a general explanation of the acetaldehyde-induced inactivation mechanism is missing. Results Based on five microbial lipases from Candida rugosa, Rhizopus oryzae, Pseudomonas fluorescens and Bacillus subtilis we demonstrate that the protonation state of lysine ε-amino groups is decisive for their sensitivity toward acetaldehyde. Analysis of the diverse modification products of Bacillus subtilis lipases in the presence of acetaldehyde revealed several stable products such as α,β-unsaturated polyenals, which result from base and/or amino acid catalyzed aldol condensation of acetaldehyde. Our studies indicate that these products induce the formation of stable Michael-adducts at solvent-accessible amino acids and thus lead to enzyme deactivation. Further, our results indicate Schiff-base formation with acetaldehyde to be involved in crosslinking of lipase molecules. Conclusions Differences in stability observed with various commercially available microbial lipases most probably result from different purification procedures carried out by the respective manufacturers. We observed that the pH of the buffer used prior to lyophilization of the enzyme sample is of utmost importance. The mechanism of acetaldehyde-induced deactivation of microbial lipases involves the generation of α,β-unsaturated polyenals from acetaldehyde which subsequently form stable Michael-adducts with the enzymes. Lyophilization of the enzymes from buffer at pH 6.0 can provide an easy and effective way to stabilize lipases toward inactivation by acetaldehyde.
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Affiliation(s)
- Benjamin Franken
- Institute of Molecular Enzyme Technology, Heinrich-Heine University Düsseldorf, Forschungszentrum Jülich GmbH, D-52426 Jülich, Germany
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18
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Brun E, Blouquit Y, Duchambon P, Malosse C, Chamot-Rooke J, Sicard-Roselli C. Oxidative stress induces mainly human centrin 2 polymerisation. Int J Radiat Biol 2010; 86:657-68. [PMID: 20586543 DOI: 10.3109/09553001003734584] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE To determine the human centrin 2 (Hscen 2) protein response to oxidising radicals in vitro and to evaluate the consequences on its biological functions. MATERIALS AND METHODS Hscen 2 was submitted to hydroxyl and azide radicals produced by radiolysis in the absence of oxygen. The resulting products were characterised by biochemical, spectroscopic and mass spectrometry techniques. Their thermodynamics parameters of complexation with C-terminal fragment of Xeroderma pigmentosum C protein (C-XPC), one of the Hscen 2 cellular partners, were quantified by isothermal titration calorimetry (ITC). RESULTS Both hydroxyl and azide radicals induce centrin 2 polymerisation as we characterised several intermolecular cross-links generating dimers, trimers, tetramers and higher molecular mass species. These cross-links result from the formation of a covalent bond between the only tyrosine residue (Tyr 172) located in the C-terminal region of each monomer. Remarkably, dimerisation occurs for doses as low as a few grays. Moreover, this Hscen2 dimer has a lower affinity and stoechiometry binding to C-XPC. CONCLUSIONS These results show that as oxidative radicals induce high proportions of irreversible damages (polymerisation) centrin 2 is highly sensitive to ionising radiation. This could have important consequences on its biological functions.
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Affiliation(s)
- Emilie Brun
- Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud 11, Bât. 350, Orsay Cedex, France
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19
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Site-Saturation Mutagenesis of Leucine 134 of Bacillus licheniformis Nucleotide Exchange Factor GrpE Reveals the Importance of this Residue to the Co-chaperone Activity. Protein J 2010; 29:365-72. [DOI: 10.1007/s10930-010-9261-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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20
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Mass spectrometric analysis of Ehrlichia chaffeensis tandem repeat proteins reveals evidence of phosphorylation and absence of glycosylation. PLoS One 2010; 5:e9552. [PMID: 20209062 PMCID: PMC2832021 DOI: 10.1371/journal.pone.0009552] [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: 11/11/2009] [Accepted: 02/12/2010] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Ehrlichia chaffeensis has a small subset of immunoreactive secreted, acidic (pI approximately 4), tandem repeat (TR)-containing proteins (TRPs), which exhibit abnormally large electrophoretic masses that have been associated with glycosylation of the TR domain. METHODOLOGY/PRINCIPAL FINDINGS In this study, we examined the extent and nature of posttranslational modifications on the native TRP47 and TRP32 using mass spectrometry. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) demonstrated that the mass of native TRP47 (33,104.5 Da) and TRP32 (22,736.8 Da) were slightly larger (179- and 288-Da, respectively) than their predicted masses. The anomalous migration of native and recombinant TRP47, and the recombinant TR domain (C-terminal region) were normalized by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) modification of negatively charged carboxylates to neutral amides. Exhaustive tandem mass spectrometric analysis (92% coverage) performed on trypsin and Asp-N digested native TRP47 identified peptides consistent with their predicted masses. Two TRP47 peptides not identified were located in the normally migrating amino (N)-terminal region of TRP47 and contained predicted phosphorylation sites (tyrosine and serine residues). Moreover, native TRP47 was immunoprecipitated from E. chaffeensis-infected cell lysate with anti-phosphotyrosine (anti-pTyr) antibody. CONCLUSIONS/SIGNIFICANCE TRP47 and TRP32 are not modified by glycans and the substantial net negative charge of the ehrlichial TRPs, and particularly the highly acidic TRs present within the ehrlichial TRPs, is responsible for larger-than-predicted masses. Furthermore, this study provides evidence that the N-terminal region of the TRP47 is tyrosine phosphorylated.
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21
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Molecular characterization of antibody epitopes of Ehrlichia chaffeensis ankyrin protein 200 and tandem repeat protein 47 and evaluation of synthetic immunodeterminants for serodiagnosis of human monocytotropic ehrlichiosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 17:87-97. [PMID: 19955322 DOI: 10.1128/cvi.00331-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Recently, major species-specific antibody epitopes in three immunoreactive tandem repeat proteins (TRPs) of Ehrlichia chaffeensis, TRP32, TRP47, and TRP120, have been identified and molecularly characterized within tandem repeat (TR) regions. In this study, we mapped the major immunodeterminants of the E. chaffeensis 200-kDa ankyrin protein (Ank200) and the minor immunodeterminants in the N- and C-terminal regions of E. chaffeensis TRP47. Major antibody epitopes of Ank200 were localized to four polypeptide regions (18-mer, 20-mer, 20-mer, and 21-mer, respectively) in terminal acidic domains, which reacted with antibodies in sera from human monocytotropic ehrlichiosis (HME) patients and an E. chaffeensis-infected dog. Two minor epitope-containing regions were identified in the N terminus and the C terminus of TRP47. The sensitivities and specificities of synthetic peptides representing these and other well-defined major immunodeterminants of E. chaffeensis were determined by enzyme-linked immunosorbent assay (ELISA). Thirty-one HME patient serum samples that had detectable E. chaffeensis antibodies (titers from 64 to 8,192) by indirect fluorescent-antibody assay (IFA) were tested. All 31 serum samples reacted with at least one E. chaffeensis peptide, 30 (96.8%) with TRP120 peptides, 27 (87.1%) with TRP32 peptides, 24 (77.4%) with TRP47 peptides, 19 (61.3%) with Ank200 peptides, and 28 (90.3%) with recombinant TRP120-TR protein. A mixture of the two most sensitive peptides from TRP120 and TRP32 did not provide enhanced analytical sensitivity compared to that provided by TRP120 alone. Our results demonstrate that the TRP120 peptide can be utilized for development of standardized sensitive point-of-care and reference laboratory immunodiagnostics for HME. This is the first study to compare analysis of molecularly defined major antibody epitopes with IFA for diagnosis of HME.
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Production of the biotechnologically relevant AFP from Aspergillus giganteus in the yeast Pichia pastoris. Protein Expr Purif 2009; 70:206-10. [PMID: 19896535 DOI: 10.1016/j.pep.2009.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/03/2009] [Accepted: 11/03/2009] [Indexed: 11/23/2022]
Abstract
The mould Aspergillus giganteus produces a basic, low molecular weight protein (AFP) showing in vitro and in vivo antifungal properties against important plant pathogens. AFP is secreted as an inactive precursor containing an amino-terminal extension of six amino acids (lf-AFP) which is later removed to produce the active protein. The molecular basis to explain this behavior and the features that determine the fungal specificity of this protein are not completely solved. In this work, the mature AFP (AFP *) and a version of AFP with an extended amino-terminal (proAFP) have been cloned and produced in the yeast Pichia pastoris. The two proteins have been purified to homogeneity and characterized from structural and functional points of view. Recombinant AFP * produced is practically indistinguishable from the natural fungal protein in terms of its spectroscopic and antifungal properties while proAFP is mostly inactive under identical assay conditions. The availability of an active AFP protein produced in P. pastoris will permit investigation of the mode of action and targeting specificity of AFP by using site-directed mutagenesis approaches.
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Byrne-Steele ML, Hughes RC, Ng JD. Recombinant production, crystallization and preliminary X-ray analysis of PCNA from the psychrophilic archaeon Methanococcoides burtonii DSM 6242. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:1131-5. [PMID: 19923734 PMCID: PMC2777042 DOI: 10.1107/s1744309109037075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 09/13/2009] [Indexed: 11/10/2022]
Abstract
Proliferating cell nuclear antigen (PCNA) is a DNA-clamping protein that is responsible for increasing the processivity of the replicative polymerases during DNA replication and repair. The PCNA from the eurypsychrophilic archaeon Methanococcoides burtonii DSM 6242 (MbPCNA) has been targeted for protein structural studies. A recombinant expression system has been created that overproduces MbPCNA with an N-terminal hexahistidine affinity tag in Escherichia coli. As a result, recombinant MbPCNA with a molecular mass of 28.3 kDa has been purified to at least 95% homogeneity and crystallized by vapor-diffusion equilibration. Preliminary X-ray analysis revealed a trigonal hexagonal R3 space group, with unit-cell parameters a = b = 102.5, c = 97.5 angstrom. A singleMbPCNA crystal was subjected to complete diffraction data-set collection using synchrotron radiation and reflections were measured to 2.40 angstrom resolution. The diffraction data were of suitable quality for indexing and scaling and an unrefined molecular-replacement solution has been obtained.
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Nie Z, Lv Z, Qian J, Chen J, Li S, Sheng Q, Wang D, Shen H, Yu W, Wu X, Zhang Y. Molecular cloning and expression characterization of translationally controlled tumor protein in silkworm pupae. Mol Biol Rep 2009; 37:2621-8. [PMID: 19757184 DOI: 10.1007/s11033-009-9787-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Accepted: 08/31/2009] [Indexed: 12/11/2022]
Abstract
A Bombyx mori (B. mori) cDNA was isolated from silkworm pupae cDNA library encoding a homologue of translationally controlled tumor protein (BmTCTPk). BmTCTPk was expressed in E. coli; SDS-PAGE and Western blot showed the molecular weight of recombinant and native BmTCTPk is approximately 28 and 25 kDa, respectively; they are larger than the theoretical molecular weight. Immunohistochemical studies showed that BmTCTPk is uniformly distributed throughout the cytoplasm of BmN cells. In silkworm pupae, BmTCTPk is expressed in the midgut wall, the midgut cavity, and some fat body tissues lying between the midgut wall and body wall. Western blot and ELISAs performed on total protein extracts isolated from silkworm pupae at different development stages showed that, although BmTCTPk is expressed during all pupae stages, its expression level increases dramatically during late pupae stages, suggesting that BmTCTPk may play an important role during the developmental transition from pupa to imago.
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Affiliation(s)
- Zuoming Nie
- Institute of Biochemistry, Zhejiang Sci-Tech University, Xiasha High-Tech Zone, No. 2 Road, 310018 Hangzhou, People's Republic of China
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25
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Calvel P, Kervarrec C, Lavigne R, Vallet-Erdtmann V, Guerrois M, Rolland AD, Chalmel F, Jégou B, Pineau C. CLPH, a novel casein kinase 2-phosphorylated disordered protein, is specifically associated with postmeiotic germ cells in rat spermatogenesis. J Proteome Res 2009; 8:2953-65. [PMID: 19271754 DOI: 10.1021/pr900082m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a recent proteomic study of rat spermatogenesis, we identified CLPH (for Casein-Like PHosphoprotein), a new testis-specific protein expressed exclusively in postmeiotic germ cells. In situ hybridization showed that the CLPH transcript was mainly present in round spermatids, whereas the protein was specifically detected by immunohistochemistry in elongated spermatids and in residual bodies. Electron microscopy showed the protein to be mostly cytoplasmic, but also frequently associated with the mitochondrial inner membrane during the last steps of spermatid differentiation. The Clph gene was found to be present solely in mammalian genomes, in a chromosomal region syntenic to the mammalian cluster of secretory calcium-binding phosphoprotein (SCPP) genes. CLPH has several distinctive properties in common with SCPPs: calcium overlay experiments showed that CLPH was a calcium-binding protein, whereas trypsin digestion assay, circular dichroism and fluorescence experiments demonstrated its intrinsically disordered structure. We also showed that CLPH was phosphorylated in vitro and in vivo by casein kinase 2, an enzyme critical for spermatid elongation. Given the specific and strong production of CLPH during rat spermiogenesis, together with the particular biochemical properties of this protein, we suggest that CLPH is involved in the extremely complex structural rearrangements occurring in haploid germ cells during spermiogenesis.
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Affiliation(s)
- Pierre Calvel
- Inserm, U625, Rennes, Universite Rennes I, Campus de Beaulieu, IFR-140, GERHM, Rennes, F-35042, France
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Alvarez-García E, García-Ortega L, De los Ríos V, Gavilanes JG, Martínez-del-Pozo A. Influence of key residues on the heterologous extracellular production of fungal ribonuclease U2 in the yeast Pichia pastoris. Protein Expr Purif 2009; 65:223-9. [PMID: 19297697 DOI: 10.1016/j.pep.2009.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Ribonuclease U2, secreted by the smut fungus Ustilago sphaerogena, is a cyclizing ribonuclease that displays a rather unusual specificity within the group of microbial extracellular RNases, best represented by RNase T1. Superposition of the three-dimensional structures of RNases T1 and U2 suggests that the RNase U2 His 101 would be the residue equivalent to the RNase T1 catalytically essential His 92. RNase U2 contains three disulfide bridges but only two of them are conserved among the family of fungal extracellular RNases. The non-conserved disulfide bond is established between Cys residues 1 and 54. Mispairing of the disulfide network due to the presence of two consecutive Cys residues (54 and 55) has been invoked to explain the presence of wrongly folded RNase U2 species when produced in Pichia pastoris. In order to study both hypotheses, the RNase U2 H101Q and C1/54S variants have been produced, purified, and characterized. The results obtained support the major conclusion that His 101 is required for proper protein folding when secreted by the yeast P. pastoris. On the other hand, substitution of the first Cys residue for Ser results in a mutant version which is more efficiently processed in terms of a more complete removal of the yeast alpha-factor signal peptide. In addition, it has been shown that elimination of the Cys 1-Cys 54 disulfide bridge does not interfere with RNase U2 proper folding, generating a natively folded but much less stable protein.
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Affiliation(s)
- Elisa Alvarez-García
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense, Avenida Complutense s/n, Ciudad Universitaria, 28040 Madrid, Spain
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Major species-specific antibody epitopes of the Ehrlichia chaffeensis p120 and E. canis p140 orthologs in surface-exposed tandem repeat regions. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:982-90. [PMID: 19420187 DOI: 10.1128/cvi.00048-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ehrlichia chaffeensis and E. canis have a small subset of tandem repeat (TR)-containing protein orthologs, including p120/p140, which elicit strong antibody responses. The TR regions of these protein orthologs are immunoreactive, but the molecular characteristics of the p120/p140 epitopes have not been determined. In this study, the immunodeterminants of the E. chaffeensis p120 and E. canis p140 were identified and molecularly defined. Major antibody epitope-containing regions of both p120 and p140 were localized to the TR regions, which reacted strongly by Western immunoblotting with antibodies in sera from E. chaffeensis-infected dogs or patients and E. canis-infected dogs, respectively. Single continuous species-specific major epitopes within the E. chaffeensis p120 and E. canis p140 TRs were mapped to homologous surface-exposed glutamate/aspartate-rich regions (19 to 22 amino acids). In addition, minor cross-reactive epitopes were localized to homologous N- and C-terminal regions of p120 and p140. Furthermore, although the native and recombinant p120 and p140 proteins exhibited higher-than-predicted molecular masses, posttranslational modifications were not present on abnormally migrating p120 and p140 TR recombinant proteins as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry.
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28
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Selcuk Unal E, Zhao R, Qiu A, Goldman ID. N-linked glycosylation and its impact on the electrophoretic mobility and function of the human proton-coupled folate transporter (HsPCFT). BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1778:1407-14. [PMID: 18405659 PMCID: PMC2762823 DOI: 10.1016/j.bbamem.2008.03.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 03/07/2008] [Accepted: 03/07/2008] [Indexed: 01/26/2023]
Abstract
The human proton-coupled folate transporter (HsPCFT, SLC46A1) mediates intestinal absorption of folates and transport of folates into the liver, brain and other tissues. On Western blot, HsPCFT migrates as a broad band (~55 kDa), higher than predicted (~50 kDa) in cell lines. Western blot analysis required that membrane preparations not be incubated in the loading buffer above 50 degrees C to avoid aggregation of the protein. Treatment of membrane fractions from HsPCFT-transfected HeLa cells with peptidyl N-glycanase F, or cells with tunicamycin, resulted in conversion to a ~35 kDa species. Substitution of asparagine residues of two canonical glycosylation sites to glutamine, individually, yielded a ~47 kDa protein; substitution of both sites gave a smaller (~35 kDa) protein. Single mutants retained full transport activity; the double mutant retained a majority of activity. Transport function and molecular size were unchanged when the double mutant was hemagglutinin (HA) tagged at either the NH(2) or COOH terminus and probed with an anti-HA antibody excluding degradation of the deglycosylated protein. Wild-type or deglycosylated HsPCFT HA, tagged at amino or carboxyl termini, could only be visualized on the plasma membrane when HeLa cells were first permeabilized, consistent with the intracellular location of these domains.
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Key Words
- rfc, reduced folate carrier
- pcft, proton-coupled folate transporter
- slc, solute carrier family
- tmds, transmembrane domains
- pngasef, peptide-n4-(n-acetyl-β-d-glucosaminyl)asparagine amidase f
- endo h, endo-β-n-acetylglucosaminidase h
- mtx, methotrexate
- dtt, dithiothreitol
- sds-page, sodium dodecyl sulfate polyacrylamide gel electrophoresis
- omim, online mendelian inheritance in man
- hcp1
- pcft/hcp1
- pcft glycosylation
- folate transport
- intestinal folate absorption
- pcft secondary structure
- hereditary folate malabsorption (hfm)
- slc46a1
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Affiliation(s)
- Ersin Selcuk Unal
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Rongbao Zhao
- Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Andong Qiu
- Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - I. David Goldman
- Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Corresponding author. Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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An abundant evolutionarily conserved CSB-PiggyBac fusion protein expressed in Cockayne syndrome. PLoS Genet 2008; 4:e1000031. [PMID: 18369450 PMCID: PMC2268245 DOI: 10.1371/journal.pgen.1000031] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Accepted: 02/11/2008] [Indexed: 12/27/2022] Open
Abstract
Cockayne syndrome (CS) is a devastating progeria most often caused by mutations in the CSB gene encoding a SWI/SNF family chromatin remodeling protein. Although all CSB mutations that cause CS are recessive, the complete absence of CSB protein does not cause CS. In addition, most CSB mutations are located beyond exon 5 and are thought to generate only C-terminally truncated protein fragments. We now show that a domesticated PiggyBac-like transposon PGBD3, residing within intron 5 of the CSB gene, functions as an alternative 3′ terminal exon. The alternatively spliced mRNA encodes a novel chimeric protein in which CSB exons 1–5 are joined in frame to the PiggyBac transposase. The resulting CSB-transposase fusion protein is as abundant as CSB protein itself in a variety of human cell lines, and continues to be expressed by primary CS cells in which functional CSB is lost due to mutations beyond exon 5. The CSB-transposase fusion protein has been highly conserved for at least 43 Myr since the divergence of humans and marmoset, and appears to be subject to selective pressure. The human genome contains over 600 nonautonomous PGBD3-related MER85 elements that were dispersed when the PGBD3 transposase was last active at least 37 Mya. Many of these MER85 elements are associated with genes which are involved in neuronal development, and are known to be regulated by CSB. We speculate that the CSB-transposase fusion protein has been conserved for host antitransposon defense, or to modulate gene regulation by MER85 elements, but may cause CS in the absence of functional CSB protein. For reasons that are still unclear, genetic defects in DNA repair can cause diseases that resemble aspects of premature ageing (“segmental progerias”). Cockayne syndrome (CS) is a particularly devastating progeria most commonly caused by mutations in the CSB chromatin remodeling gene. About 43 million years ago, before humans diverged from marmosets, one of the last PiggyBac transposable elements to invade the human lineage landed within intron 5 of the 21 exon CSB gene. As a result, the CSB locus now encodes two equally abundant proteins generated by alternative mRNA splicing: the original full length CSB protein, and a novel CSB-PiggyBac fusion protein in which the N-terminus of CSB is fused to the complete PiggyBac transposase. Conservation of the CSB-PiggyBac fusion protein since marmoset suggests that it is normally beneficial, demonstrating once again that “selfish” transposable elements can be exploited or “domesticated” by the host. More importantly, almost all CSB mutations that cause CS continue to make the CSB-PiggyBac fusion protein, whereas a mutation that compromises both does not cause CS. Thus the fusion protein which is beneficial in the presence of functional CSB may be harmful in its absence. This may help clarify the cause of CS and other progerias.
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Abstract
Voltage-gated potassium (K(V)) channels can form heteromultimeric complexes with a variety of accessory subunits, including KCNE proteins. Heterologous expression studies have demonstrated diverse functional effects of KCNE subunits on several K(V) channels, including KCNQ1 (K(V)7.1) that, together with KCNE1, generates the slow-delayed rectifier current (I(Ks)) important for cardiac repolarization. In particular, KCNE4 exerts a strong inhibitory effect on KCNQ1 and other K(V) channels, raising the possibility that this accessory subunit is an important potassium current modulator. A polyclonal KCNE4 antibody was developed to determine the human tissue expression pattern and to investigate the biochemical associations of this protein with KCNQ1. We found that KCNE4 is widely and variably expressed in several human tissues, with greatest abundance in brain, liver and testis. In heterologous expression experiments, immunoprecipitation followed by immunoblotting was used to establish that KCNE4 directly associates with KCNQ1, and can co-associate together with KCNE1 in the same KCNQ1 complex to form a 'triple subunit' complex (KCNE1-KCNQ1-KCNE4). We also used cell surface biotinylation to demonstrate that KCNE4 does not impair plasma membrane expression of either KCNQ1 or the triple subunit complex, indicating that biophysical mechanisms probably underlie the inhibitory effects of KCNE4. The observation that multiple KCNE proteins can co-associate with and modulate KCNQ1 channels to produce biochemically diverse channel complexes has important implications for understanding K(V) channel regulation in human physiology.
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Affiliation(s)
- Lauren J Manderfield
- Department of Pharmacology, Vanderbilt University, 2215 Garland Avenue, Nashville, TN 37232, USA
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Loehfelm TW, Luke NR, Campagnari AA. Identification and characterization of an Acinetobacter baumannii biofilm-associated protein. J Bacteriol 2008; 190:1036-44. [PMID: 18024522 PMCID: PMC2223572 DOI: 10.1128/jb.01416-07] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 11/07/2007] [Indexed: 01/01/2023] Open
Abstract
We have identified a homologue to the staphylococcal biofilm-associated protein (Bap) in a bloodstream isolate of Acinetobacter baumannii. The fully sequenced open reading frame is 25,863 bp and encodes a protein with a predicted molecular mass of 854 kDa. Analysis of the nucleotide sequence reveals a repetitive structure consistent with bacterial cell surface adhesins. Bap-specific monoclonal antibody (MAb) 6E3 was generated to an epitope conserved among 41% of A. baumannii strains isolated during a recent outbreak in the U.S. military health care system. Flow cytometry confirms that the MAb 6E3 epitope is surface exposed. Random transposon mutagenesis was used to generate A. baumannii bap1302::EZ-Tn5, a mutant negative for surface reactivity to MAb 6E3 in which the transposon disrupts the coding sequence of bap. Time course confocal laser scanning microscopy and three-dimensional image analysis of actively growing biofilms demonstrates that this mutant is unable to sustain biofilm thickness and volume, suggesting a role for Bap in supporting the development of the mature biofilm structure. This is the first identification of a specific cell surface protein directly involved in biofilm formation by A. baumannii and suggests that Bap is involved in intercellular adhesion within the mature biofilm.
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Affiliation(s)
- Thomas W Loehfelm
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, The State University of New York 14214, USA
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A variable-length PCR target protein of Ehrlichia chaffeensis contains major species-specific antibody epitopes in acidic serine-rich tandem repeats. Infect Immun 2008; 76:1572-80. [PMID: 18212082 DOI: 10.1128/iai.01466-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ehrlichia chaffeensis and E. canis have a small subset of tandem repeat (TR)-containing proteins that elicit strong host immune responses and are associated with host-pathogen interactions. In a previous study, we molecularly characterized a highly conserved 19-kDa major immunoreactive protein (gp19) of E. canis and identified the corresponding TR-containing ortholog variable-length PCR target (VLPT) protein in E. chaffeensis. In this study, the native 32-kDa VLPT protein was identified and the immunodeterminants defined in order to further understand the molecular basis of the host immune response to E. chaffeensis. Synthetic and/or recombinant polypeptides corresponding to various regions of VLPT were used to localize major antibody epitopes to the TR-containing region. Major antibody epitopes were identified in three nonidentical repeats (R2, R3, and R4), which reacted strongly with antibodies in sera from an E. chaffeensis-infected dog and human monocytotropic ehrlichiosis patients. VLPT-R3 and VLPT-R2 reacted most strongly with antibody, and the epitope was further localized to a nearly identical proximal 17-amino-acid region common between these repeats that was species specific. The epitope in R4 was distinct from that of R2 and R3 and was found to have conformational dependence. VLPT was detected in supernatants from infected cells, indicating that the protein was secreted. VLPT was localized on both reticulate and dense-core cells, and it was found extracellularly in the morula fibrillar matrix and associated with the morula membrane.
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Economopoulou MAI, Fragoulis EG, Sideris DC. Molecular cloning and characterization of the human RNase kappa, an ortholog of Cc RNase. Nucleic Acids Res 2007; 35:6389-98. [PMID: 17881363 PMCID: PMC2095791 DOI: 10.1093/nar/gkm718] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A novel protein family, designated hereafter as RNase κ (kappa) family, has been recently introduced with the characterization of the specific Cc RNase, isolated from the insect Ceratitis capitata. The human ortholog of this family consists of 98 amino acids and shares > 98% identity with its mammalian counterparts. This RNase is encoded by a single-copy gene found to be expressed in a wide spectrum of normal and cancer tissues. The cDNA of the human ribonuclease has been isolated and subcloned into a variety of prokaryotic expression vectors, but most efforts to express it caused a severe toxic effect. On the other hand, the expression of the human RNase by the use of the methylotrophic yeast Pichia pastoris system resulted in the production of a highly active recombinant enzyme. Using a 30-mer 5′-end-labeled RNA probe as substrate, the purified enzyme seems to preferentially cleave ApU and ApG phosphodiester bonds, while it hydrolyzes UpU bonds at a lower rate. Based on amino acid sequence alignment and substrate specificity data, as well as the complete resistance of the recombinant protein to the placental ribonuclease inhibitor, we concluded that the human RNase κ is a novel endoribonuclease distinct from other known ribonucleases.
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Petty AP, Garman KL, Winn VD, Spidel CM, Lindsey JS. Overexpression of carcinoma and embryonic cytotrophoblast cell-specific Mig-7 induces invasion and vessel-like structure formation. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1763-80. [PMID: 17456780 PMCID: PMC1854969 DOI: 10.2353/ajpath.2007.060969] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Molecular requirements for carcinoma cell interactions with the microenvironment are critical for disease progression but are poorly understood. Integrin alpha v beta 5, which senses the extracellular matrix, is important for carcinoma cell dissemination in vivo. alpha v beta 5 signaling induces Mig-7, a novel human gene product that is apparently carcinoma-specific. We hypothesized that Mig-7 expression facilitates tumor cell dissemination by increasing invasion and vasculogenic mimicry. Results show that embryonic cytotrophoblasts up-regulated Mig-7 expression before they acquired an invasive phenotype capable of pseudovasculogenesis. Mig-7 protein primarily co-localized with vasculogenic mimicry markers factor VIII-associated antigen, vascular endothelial-cadherin, and laminin 5 gamma 2 chain domain III fragment in lymph node metastases. Overexpression of Mig-7 increased gamma 2 chain domain III fragments known to contain epidermal growth factor (EGF)-like repeats that can activate EGF receptor. Interestingly, EGF also induced Mig-7 expression. Carcinoma cell adhesion to laminins was significantly reduced by Mig-7 expression. Remarkably, in two-dimensional and three-dimensional Matrigel cultures, Mig-7 expression caused invasion and vessel-like structures. Melanoma cells, which were previously characterized to invade aggressively and to undergo vasculogenic mimicry, expressed Mig-7. Taken together, these data suggest that Mig-7 expression allows cells to sense their environment, to invade, and to form vessel-like structures through a novel relationship with laminin 5 gamma 2 chain domain III fragments.
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Affiliation(s)
- Aaron P Petty
- School of Molecular Biosciences, Washington State University, Wegner Hall, Pullman, WA 99164-6534, USA
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Su Y, Zou Z, Feng S, Zhou P, Cao L. The acidity of protein fusion partners predominantly determines the efficacy to improve the solubility of the target proteins expressed in Escherichia coli. J Biotechnol 2007; 129:373-82. [PMID: 17374413 DOI: 10.1016/j.jbiotec.2007.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2006] [Revised: 01/14/2007] [Accepted: 01/18/2007] [Indexed: 11/17/2022]
Abstract
Maximization of the soluble protein expression in Escherichia coli (E. coli) via the fusion expression strategy is usually preferred for academic, industrial and pharmaceutical purposes. In this study, a set of distinct protein fusion partners were comparatively evaluated to promote the soluble expression of two target proteins including the bovine enterokinase largely prone to aggregation and the green fluorescent protein with moderate native solubility. Within protein attributes that are putatively involved in protein solubility, the protein acidity was of particular concern. Our results explicitly indicated the protein fusion partners with a stronger acidity remarkably exhibited a higher capacity to enhance the solubility of the target proteins. Among them, msyB, an E. coli acidic protein that suppresses the mutants lacking function of protein export, was revealed as an excellent protein fusion partner with the distinguished features including high potential to enhance protein solubility, efficient expression, relatively small size and the origin of E. coli itself. In principle, our results confirmed the modified solubility model of Wilkinson-Harrison and especially deepened understanding its essence. Meanwhile, the roles of other parameters such as protein hydrophilicity in solubility enhancement were discussed, a guideline to design or search an optimum protein solubility enhancer was also proposed.
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Affiliation(s)
- Yu Su
- School of Life Sciences, East China Normal University, Zhongshan North Road 3663, Shanghai 200062, China
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Sebban-Kreuzer C, Deprez-Beauclair P, Berton A, Crenon I. High-level expression of nonglycosylated human pancreatic lipase-related protein 2 in Pichia pastoris. Protein Expr Purif 2006; 49:284-91. [PMID: 16861001 DOI: 10.1016/j.pep.2006.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 05/28/2006] [Accepted: 06/01/2006] [Indexed: 11/28/2022]
Abstract
The human pancreatic lipase-related protein 2 (HPLRP2) was produced in the methylotrophic yeast Pichia pastoris. The HPLRP2 cDNA corresponding to the protein coding sequence including the native signal sequence, was cloned into the pPIC9K vector and integrated into the genome of P. pastoris. P. pastoris transformants secreting high-level rHPLRP2 were obtained and the expression level into the liquid culture medium reached about 40mg/L after 4 days of culture. rHPLRP2 was purified by a single anion-exchange step after an overnight dialysis. N-terminal sequence analysis showed that the purified rHPLRP2 mature protein possessed a correct N-terminal amino acid sequence indicating that its signal peptide was properly processed. Mass spectrometry analysis showed that the recombinant HPLRP2 molecular weight was 52,532Da which was 2451Da greater than the mass calculated from the sequence of the protein (50,081Da) and 1536Da greater than the mass of the native human protein (50,996Da). In vitro deglycosylation experiments by peptide:N-glycosidase F (PNGase F) indicated that rHPLRP2 secreted from P. pastoris was N-glycosylated. Specific conditions were setup in order to obtain a recombinant protein free of glycan chain. We observed that blocking glycosylation in vivo by addition of tunicamycin in the culture medium during the production resulted in a correct processing of the rHPLRP2 mature protein. The lipase activity of glycosylated or nonglycosylated rHPLRP2, which was about 800U/mg on tributyrin, was inhibited by the presence of bile salts and not restored by adding colipase. In conclusion, the experimental procedure which we have developed will allow us to get a high-level production in P. pastoris of glycosylated and nonglycosylated rHPLRP2, suitable for subsequent biophysical and structural studies.
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