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Li JY, Zhou CM, Jin RL, Song JH, Yang KC, Li SL, Tan BH, Li YC. The detection methods currently available for protein aggregation in neurological diseases. J Chem Neuroanat 2024; 138:102420. [PMID: 38626816 DOI: 10.1016/j.jchemneu.2024.102420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/30/2024] [Accepted: 04/13/2024] [Indexed: 04/21/2024]
Abstract
Protein aggregation is a pathological feature in various neurodegenerative diseases and is thought to play a crucial role in the onset and progression of neurological disorders. This pathological phenomenon has attracted increasing attention from researchers, but the underlying mechanism has not been fully elucidated yet. Researchers are increasingly interested in identifying chemicals or methods that can effectively detect protein aggregation or maintain protein stability to prevent aggregation formation. To date, several methods are available for detecting protein aggregates, including fluorescence correlation spectroscopy, electron microscopy, and molecular detection methods. Unfortunately, there is still a lack of methods to observe protein aggregation in situ under a microscope. This article reviews the two main aspects of protein aggregation: the mechanisms and detection methods of protein aggregation. The aim is to provide clues for the development of new methods to study this pathological phenomenon.
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Affiliation(s)
- Jing-Yi Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Cheng-Mei Zhou
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Rui-Lin Jin
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Jia-Hui Song
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China; Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun 130021, PR China
| | - Ke-Chao Yang
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Shu-Lei Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Bai-Hong Tan
- Laboratory Teaching Center of Basic Medicine, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China
| | - Yan-Chao Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Changchun city, Jilin Province 130021, PR China; Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun 130021, PR China.
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2
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Bhondwe P, Sengar N, Bodiwala HS, Singh IP, Panda D. An adamantyl-caffeoyl-anilide exhibits broad-spectrum antibacterial activity by inhibiting FtsZ assembly and Z-ring formation. Int J Biol Macromol 2024; 259:129255. [PMID: 38199552 DOI: 10.1016/j.ijbiomac.2024.129255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/01/2024] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Abstract
Several harmful bacteria have evolved resistance to conventional antibiotics due to their extensive usage. FtsZ, a principal bacterial cell division protein, is considered as an important drug target to combat resistance. We identified a caffeoyl anilide derivative, (E)-N-(4-(3-(3,4-dihydroxyphenyl)acryloyl)phenyl)-1-adamantylamide (compound 11) as a new antimicrobial agent targeting FtsZ. Compound 11 caused cell elongation in Mycobacterium smegmatis, Bacillus subtilis, and Escherichia coli cells, indicating that it inhibits cell partitioning. Compound 11 inhibited the assembly of Mycobacterium smegmatis FtsZ (MsFtsZ), forming short and thin filaments in vitro. Interestingly, the compound increased the rate of GTP hydrolysis of MsFtsZ. Compound 11 also impeded the assembly of Mycobacterium tuberculosis FtsZ. Fluorescence and absorption spectroscopic analysis suggested that compound 11 binds to MsFtsZ and produces conformational changes in FtsZ. The docking analysis indicated that the compound binds at the interdomain cleft of MsFtsZ. Further, it caused delocalization of the Z-ring in Mycobacterium smegmatis and Bacillus subtilis without affecting DNA segregation. Notably, compound 11 did not inhibit tubulin polymerization, the eukaryotic homolog of FtsZ, suggesting its specificity on bacteria. The evidence indicated that compound 11 exerts its antibacterial effect by impeding FtsZ assembly and has the potential to be developed as a broad-spectrum antimicrobial agent.
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Affiliation(s)
- Prajakta Bhondwe
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Neha Sengar
- Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali 160062, Punjab, India
| | - Hardik S Bodiwala
- Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali 160062, Punjab, India
| | - Inder Pal Singh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali 160062, Punjab, India
| | - Dulal Panda
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India; Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali 160062, Punjab, India.
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3
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Shinde Y, Pathan A, Chinnam S, Rathod G, Patil B, Dhangar M, Mathew B, Kim H, Mundada A, Kukreti N, Ahmad I, Patel H. Mycobacterial FtsZ and inhibitors: a promising target for the anti-tubercular drug development. Mol Divers 2023:10.1007/s11030-023-10759-8. [PMID: 38010605 DOI: 10.1007/s11030-023-10759-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/30/2023] [Indexed: 11/29/2023]
Abstract
The emergence of multidrug-resistant tuberculosis (MDR-TB) strains has rendered many anti-TB drugs ineffective. Consequently, there is an urgent need to identify new drug targets against Mycobacterium tuberculosis (Mtb). Filament Forming Temperature Sensitive Gene Z (FtsZ), a member of the cytoskeletal protein family, plays a vital role in cell division by forming a cytokinetic ring at the cell's center and coordinating the division machinery. When FtsZ is depleted, cells are unable to divide and instead elongate into filamentous structures that eventually undergo lysis. Since the inactivation of FtsZ or alterations in its assembly impede the formation of the Z-ring and septum, FtsZ shows promise as a target for the development of anti-mycobacterial drugs. This review not only discusses the potential role of FtsZ as a promising pharmacological target for anti-tuberculosis therapies but also explores the structural and functional aspects of the mycobacterial protein FtsZ in cell division. Additionally, it reviews various inhibitors of Mtb FtsZ. By understanding the importance of FtsZ in cell division, researchers can explore strategies to disrupt its function, impeding the growth and proliferation of Mtb. Furthermore, the investigation of different inhibitors that target Mtb FtsZ expands the potential for developing effective treatments against tuberculosis.
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Affiliation(s)
- Yashodeep Shinde
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Asama Pathan
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Sampath Chinnam
- Department of Chemistry, M. S. Ramaiah Institute of Technology (Autonomous Institute, Affiliated to Visvesvaraya Technological University, Belgaum), Bengaluru, Karnataka, 560054, India
| | - Gajanan Rathod
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S. A. S. Nagar, Mohali, Punjab, 160062, India
| | - Bhatu Patil
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Mayur Dhangar
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Bijo Mathew
- Department of Pharmaceutical Chemistry, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, Kochi, 690525, India
| | - Hoon Kim
- Department of Pharmacy, and Research Institute of Life Pharmaceutical Sciences, Sunchon National University, Suncheon, 57922, Republic of Korea
| | - Anand Mundada
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Neelima Kukreti
- School of Pharmacy, Graphic Era Hill University-Dehradun, Dehradun, Uttarakhand, 248002, India
| | - Iqrar Ahmad
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India
| | - Harun Patel
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, 425405, India.
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Strand 1A variant in neuroserpin shows increased aggregation and no loss of inhibition: implication in ameliorating polymerization to retain activity. Biosci Rep 2022; 42:232125. [PMID: 36408789 PMCID: PMC9760604 DOI: 10.1042/bsr20221825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/31/2022] [Accepted: 11/18/2022] [Indexed: 11/22/2022] Open
Abstract
Neuroserpin (NS) is predominantly expressed in the brain and is the primary inhibitor of tissue plasminogen activator (tPA). NS variants are associated with the neurogenerative disease termed familial encephalopathy with neuroserpin inclusion bodies (FENIB). The disease is characterized by variable age of onset and severity. The reactive center loop (RCL) insertion-based inhibitory mechanism of NS requires a coordinated conformational change leading to a shift in the strands of the β-sheet A and movement of helix F. Strand 1A is connected to the helix F at its C terminal end and with the strand 2A at its N terminal, both these domain move for accommodating the inserting loop; therefore, a variant that influences their movement may alter the inhibition rates. A molecular dynamic simulation analysis of a H138C NS variant from strand 1A showed a large decrease in conformational fluctuations as compared with wild-type NS. H138 was mutated, expressed, purified and a native-PAGE and transmission electron microscopy (TEM) analysis showed that this variant forms large molecular weight aggregates on a slight increase in temperature. However, a circular dichroism analysis showed its secondary structure to be largely conserved. Surprisingly, its tPA inhibition activity and complex formation remain unhindered even after the site-specific labeling of H138C with Alexa fluor C5 maleimide. Further, a helix F-strand 1A (W154C-H138C) double variant still shows appreciable inhibitory activity. Increasingly, it appears that aggregation and not loss of inhibition is the more likely cause of shutter region-based variants phenotypes, indicating that hindering polymer formation using small molecules may retain inhibitory activity in pathological variants of NS.
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Vitamin K3 inhibits FtsZ assembly, disrupts the Z-ring in Streptococcus pneumoniae, and displays anti-pneumococcal activity. Biochem J 2022; 479:1543-1558. [PMID: 35789252 DOI: 10.1042/bcj20220077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/30/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022]
Abstract
The respiratory pathogen, Streptococcus pneumoniae has acquired multiple-drug resistance over the years. An attractive strategy to combat pneumococcal infection is to target cell division to inhibit the proliferation of S. pneumoniae. This work presents Vitamin K3 as a potential anti-pneumococcal drug that targets FtsZ, the master coordinator of bacterial cell division. Vitamin K3 strongly inhibited S. pneumoniae proliferation with a Minimum Inhibitory Concentration (MIC) and a Minimum Bactericidal Concentration (MBC) of 6 μg/mL. Vitamin K3 disrupted the Z-ring localization in both S. pneumoniae and Bacillus subtilis within 30 minutes of treatment, while the membrane integrity and nucleoid segregation remain unchanged. Several complementary experiments showed that Vitamin K3 inhibits the assembly of purified S. pneumoniae FtsZ (SpnFtsZ) and induces conformational changes in the protein. Interestingly, Vitamin K3 interfered with GTP-binding onto FtsZ and increased the GTPase activity of FtsZ polymers. The intrinsic tryptophan fluorescence of SpnFtsZ revealed that Vitamin K3 delays the nucleation of FtsZ polymers and reduces the rate of polymerization. In the presence of a non-hydrolyzable analog of GTP, Vitamin K3 did not show inhibition of FtsZ polymerization. These results indicated that Vitamin K3 induces conformational changes in FtsZ that increase GTP hydrolysis and thereby, destabilize the FtsZ polymers. Together, our data provide evidence that Vitamin K3 derives its potent anti-pneumococcal activity by inhibiting FtsZ assembly.
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Dhaked HPS, Ray S, Battaje RR, Banerjee A, Panda D. Regulation ofStreptococcus pneumoniaeFtsZ assembly by divalent cations: paradoxical effects of Ca2+on the nucleation and bundling of FtsZ polymers. FEBS J 2019; 286:3629-3646. [DOI: 10.1111/febs.14928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/14/2019] [Accepted: 05/13/2019] [Indexed: 01/10/2023]
Affiliation(s)
| | - Shashikant Ray
- Department of Biosciences and Bioengineering Indian Institute of Technology Bombay India
- Department of Biotechnology Mahatma Gandhi Central University Motihari Bihar India
| | - Rachana Rao Battaje
- Department of Biosciences and Bioengineering Indian Institute of Technology Bombay India
| | - Anirban Banerjee
- Department of Biosciences and Bioengineering Indian Institute of Technology Bombay India
| | - Dulal Panda
- Department of Biosciences and Bioengineering Indian Institute of Technology Bombay India
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7
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Abstract
FtsZ, a homolog of tubulin, is found in almost all bacteria and archaea where it has a primary role in cytokinesis. Evidence for structural homology between FtsZ and tubulin came from their crystal structures and identification of the GTP box. Tubulin and FtsZ constitute a distinct family of GTPases and show striking similarities in many of their polymerization properties. The differences between them, more so, the complexities of microtubule dynamic behavior in comparison to that of FtsZ, indicate that the evolution to tubulin is attributable to the incorporation of the complex functionalities in higher organisms. FtsZ and microtubules function as polymers in cell division but their roles differ in the division process. The structural and partial functional homology has made the study of their dynamic properties more interesting. In this review, we focus on the application of the information derived from studies on FtsZ dynamics to study microtubule dynamics and vice versa. The structural and functional aspects that led to the establishment of the homology between the two proteins are explained to emphasize the network of FtsZ and microtubule studies and how they are connected.
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Affiliation(s)
- Rachana Rao Battaje
- Department of Biosciences and BioengineeringIndian Institute of Technology Bombay, Mumbai, India
| | - Dulal Panda
- Department of Biosciences and BioengineeringIndian Institute of Technology Bombay, Mumbai, India
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8
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Duggirala S, Napoleon JV, Nankar RP, Senu Adeeba V, Manheri MK, Doble M. FtsZ inhibition and redox modulation with one chemical scaffold: Potential use of dihydroquinolines against mycobacteria. Eur J Med Chem 2016; 123:557-567. [PMID: 27517804 DOI: 10.1016/j.ejmech.2016.07.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/20/2016] [Accepted: 07/23/2016] [Indexed: 12/15/2022]
Abstract
The dual effect of FtsZ inhibition and oxidative stress by a group of 1,2-dihydroquinolines that culminate in bactericidal effect on mycobacterium strains is demonstrated. They inhibited the non-pathogenic Mycobacterium smegmatis mc(2) 155 with MIC as low as 0.9 μg/mL and induced filamentation. Detailed studies revealed their ability to inhibit polymerization and GTPase activity of MtbFtsZ (Mycobacterial filamentous temperature sensitive Z) with an IC50 value of ∼40 μM. In addition to such target specific effects, these compounds exerted a global cellular effect by causing redox-imbalance that was evident from overproduction of ROS in treated cells. Such multi-targeting effect with one chemical scaffold has considerable significance in this era of emerging drug resistance and could offer promise in the development of new therapeutic agents against tuberculosis.
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Affiliation(s)
- Sridevi Duggirala
- Bioengineering and Drug Design Lab, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - John Victor Napoleon
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - Rakesh P Nankar
- Bioengineering and Drug Design Lab, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - V Senu Adeeba
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600 036, India
| | | | - Mukesh Doble
- Bioengineering and Drug Design Lab, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600 036, India.
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9
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Hurley KA, Santos TMA, Nepomuceno GM, Huynh V, Shaw JT, Weibel DB. Targeting the Bacterial Division Protein FtsZ. J Med Chem 2016; 59:6975-98. [DOI: 10.1021/acs.jmedchem.5b01098] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katherine A. Hurley
- Department of Pharmaceutical Sciences, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Thiago M. A. Santos
- Department
of Biochemistry, University of Wisconsin—Madison, 440 Henry Mall, Madison, Wisconsin 53706, United States
| | - Gabriella M. Nepomuceno
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Valerie Huynh
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Jared T. Shaw
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Douglas B. Weibel
- Department
of Biochemistry, University of Wisconsin—Madison, 440 Henry Mall, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Department of Biomedical Engineering, University of Wisconsin—Madison, 1550 Engineering Drive, Madison, Wisconsin 53706, United States
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Bhattacharya A, Ray S, Singh D, Dhaked HPS, Panda D. ZapC promotes assembly and stability of FtsZ filaments by binding at a different site on FtsZ than ZipA. Int J Biol Macromol 2015; 81:435-42. [DOI: 10.1016/j.ijbiomac.2015.08.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/12/2015] [Accepted: 08/12/2015] [Indexed: 12/27/2022]
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Hernández-Rocamora VM, Alfonso C, Margolin W, Zorrilla S, Rivas G. Evidence That Bacteriophage λ Kil Peptide Inhibits Bacterial Cell Division by Disrupting FtsZ Protofilaments and Sequestering Protein Subunits. J Biol Chem 2015; 290:20325-35. [PMID: 26124275 DOI: 10.1074/jbc.m115.653329] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Indexed: 11/06/2022] Open
Abstract
The effects of Kil peptide from bacteriophage λ on the assembly of Escherichia coli FtsZ into one subunit thick protofilaments were studied using combined biophysical and biochemical methods. Kil peptide has recently been identified as the factor from bacteriophage λ responsible for the inhibition of bacterial cell division during lytic cycle, targeting FtsZ polymerization. Here, we show that this antagonist blocks FtsZ assembly into GTP-dependent protofilaments, producing a wide distribution of smaller oligomers compared with the average size of the intact protofilaments. The shortening of FtsZ protofilaments by Kil is detectable at concentrations of the peptide in the low micromolar range, the mid-point of the inhibition being close to its apparent affinity for GDP-bound FtsZ. This antagonist not only interferes with FtsZ assembly but also reverses the polymerization reaction. The negative regulation by Kil significantly reduces the GTPase activity of FtsZ protofilaments, and FtsZ polymers assembled in guanosine-5'-[(α,β)-methyleno]triphosphate are considerably less sensitive to Kil. Our results suggest that, at high concentrations, Kil may use an inhibition mechanism involving the sequestration of FtsZ subunits, similar to that described for other inhibitors like the SOS response protein SulA or the moonlighting enzyme OpgH. This mechanism is different from those employed by the division site selection antagonists MinC and SlmA. This work provides new insight into the inhibition of FtsZ assembly by phages, considered potential tools against bacterial infection.
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Affiliation(s)
- Víctor M Hernández-Rocamora
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain and
| | - Carlos Alfonso
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain and
| | - William Margolin
- the Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030
| | - Silvia Zorrilla
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain and
| | - Germán Rivas
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain and
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12
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Bacterial cell division proteins as antibiotic targets. Bioorg Chem 2014; 55:27-38. [PMID: 24755375 DOI: 10.1016/j.bioorg.2014.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 11/21/2022]
Abstract
Proteins involved in bacterial cell division often do not have a counterpart in eukaryotic cells and they are essential for the survival of the bacteria. The genetic accessibility of many bacterial species in combination with the Green Fluorescence Protein revolution to study localization of proteins and the availability of crystal structures has increased our knowledge on bacterial cell division considerably in this century. Consequently, bacterial cell division proteins are more and more recognized as potential new antibiotic targets. An international effort to find small molecules that inhibit the cell division initiating protein FtsZ has yielded many compounds of which some are promising as leads for preclinical use. The essential transglycosylase activity of peptidoglycan synthases has recently become accessible to inhibitor screening. Enzymatic assays for and structural information on essential integral membrane proteins such as MraY and FtsW involved in lipid II (the peptidoglycan building block precursor) biosynthesis have put these proteins on the list of potential new targets. This review summarises and discusses the results and approaches to the development of lead compounds that inhibit bacterial cell division.
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13
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Hernández-Rocamora VM, García-Montañés C, Reija B, Monterroso B, Margolin W, Alfonso C, Zorrilla S, Rivas G. MinC protein shortens FtsZ protofilaments by preferentially interacting with GDP-bound subunits. J Biol Chem 2013; 288:24625-35. [PMID: 23853099 DOI: 10.1074/jbc.m113.483222] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The interaction of MinC with FtsZ and its effects on FtsZ polymerization were studied under close to physiological conditions by a combination of biophysical methods. The Min system is a widely conserved mechanism in bacteria that ensures the correct placement of the division machinery at midcell. MinC is the component of this system that effectively interacts with FtsZ and inhibits the formation of the Z-ring. Here we report that MinC produces a concentration-dependent reduction in the size of GTP-induced FtsZ protofilaments (FtsZ-GTP) as demonstrated by analytical ultracentrifugation, dynamic light scattering, fluorescence correlation spectroscopy, and electron microscopy. Our experiments show that, despite being shorter, FtsZ protofilaments maintain their narrow distribution in size in the presence of MinC. The protein had the same effect regardless of its addition prior to or after FtsZ polymerization. Fluorescence anisotropy measurements indicated that MinC bound to FtsZ-GDP with a moderate affinity (apparent KD ∼10 μM at 100 mm KCl and pH 7.5) very close to the MinC concentration corresponding to the midpoint of the inhibition of FtsZ assembly. Only marginal binding of MinC to FtsZ-GTP protofilaments was observed by analytical ultracentrifugation and fluorescence correlation spectroscopy. Remarkably, MinC effects on FtsZ-GTP protofilaments and binding affinity to FtsZ-GDP were strongly dependent on ionic strength, being severely reduced at 500 mM KCl compared with 100 mM KCl. Our results support a mechanism in which MinC interacts with FtsZ-GDP, resulting in smaller protofilaments of defined size and having the same effect on both preassembled and growing FtsZ protofilaments.
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Affiliation(s)
- Víctor M Hernández-Rocamora
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain
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14
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Anderson DE, Kim MB, Moore JT, O’Brien TE, Sorto NA, Grove CI, Lackner LL, Ames JB, Shaw JT. Comparison of small molecule inhibitors of the bacterial cell division protein FtsZ and identification of a reliable cross-species inhibitor. ACS Chem Biol 2012; 7:1918-28. [PMID: 22958099 DOI: 10.1021/cb300340j] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
FtsZ is a guanosine triphosphatase (GTPase) that mediates cytokinesis in bacteria. FtsZ is homologous in structure to eukaryotic tubulin and polymerizes in a similar head-to-tail fashion. The study of tubulin's function in eukaryotic cells has benefited greatly from specific and potent small molecule inhibitors, including colchicine and taxol. Although many small molecule inhibitors of FtsZ have been reported, none has emerged as a generally useful probe for modulating bacterial cell division. With the goal of establishing a useful and reliable small molecule inhibitor of FtsZ, a broad biochemical cross-comparison of reported FtsZ inhibitors was undertaken. Several of these molecules, including phenolic natural products, are unselective inhibitors that seem to derive their activity from the formation of microscopic colloids or aggregates. Other compounds, including the natural product viriditoxin and the drug development candidate PC190723, exhibit no inhibition of GTPase activity using protocols in this work or under published conditions. Of the compounds studied, only zantrin Z3 exhibits good levels of inhibition, maintains activity under conditions that disrupt small molecule aggregates, and provides a platform for exploration of structure-activity relationships (SAR). Preliminary SAR studies have identified slight modifications to the two side chains of this structure that modulate the inhibitory activity of zantrin Z3. Collectively, these studies will help focus future investigations toward the establishment of probes for FtsZ that fill the roles of colchicine and taxol in studies of tubulin.
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Affiliation(s)
- David E. Anderson
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Michelle B. Kim
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Jared T. Moore
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Terrence E. O’Brien
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Nohemy A. Sorto
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Charles I. Grove
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Laura L. Lackner
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - James B. Ames
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Jared T. Shaw
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
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15
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Assembly of Bacillus subtilis FtsA: effects of pH, ionic strength and nucleotides on FtsA assembly. Int J Biol Macromol 2012; 52:170-6. [PMID: 23036588 DOI: 10.1016/j.ijbiomac.2012.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 08/18/2012] [Accepted: 09/25/2012] [Indexed: 11/23/2022]
Abstract
In this work, the assembly of purified Bacillus subtilis FtsA was analyzed by several complimentary techniques. FtsA assembled to form filaments and bundles and the polymers disassembled upon dilution. FtsA assembled more efficiently at pH 6.0 as compared to that at pH 7.0 or 8.0 and high salt inhibited the assembly of FtsA. FtsA was found to hydrolyze ATP in vitro; however, neither ATP nor ADP influenced the assembly kinetics of FtsA. Though FtsA is a homologue of actin, cytochalasin D did not inhibit the assembly of FtsA. Interestingly, a hydrophobic molecule, 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid, inhibited the assembly of FtsA.
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16
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Ma S, Ma S. The Development of FtsZ Inhibitors as Potential Antibacterial Agents. ChemMedChem 2012; 7:1161-72. [DOI: 10.1002/cmdc.201200156] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/05/2012] [Indexed: 11/12/2022]
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17
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Schaffner-Barbero C, Martín-Fontecha M, Chacón P, Andreu JM. Targeting the assembly of bacterial cell division protein FtsZ with small molecules. ACS Chem Biol 2012; 7:269-77. [PMID: 22047077 DOI: 10.1021/cb2003626] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
FtsZ is the key protein of bacterial cell division and an emergent target for new antibiotics. It is a filament-forming GTPase and a structural homologue of eukaryotic tubulin. A number of FtsZ-interacting compounds have been reported, some of which have powerful antibacterial activity. Here we review recent advances and new approaches in modulating FtsZ assembly with small molecules. This includes analyzing their chemical features, binding sites, mechanisms of action, the methods employed, and computational insights, aimed at a better understanding of their molecular recognition by FtsZ and at rational antibiotic design.
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Affiliation(s)
- Claudia Schaffner-Barbero
- Tubulins and
FtsZ, Centro de
Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Mar Martín-Fontecha
- Medicinal Chemistry, Dept. Química
Orgánica I, Facultad de Ciencias Químicas, UCM, Avda. Complutense s/n, 28040 Madrid, Spain
| | - Pablo Chacón
- Structural Bioinformatics, Instituto
de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain
| | - José M. Andreu
- Tubulins and
FtsZ, Centro de
Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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18
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Maarschalkerweerd AV, Wolbink GJ, Stapel SO, Jiskoot W, Hawe A. Comparison of analytical methods to detect instability of etanercept during thermal stress testing. Eur J Pharm Biopharm 2011; 78:213-21. [DOI: 10.1016/j.ejpb.2011.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/06/2011] [Accepted: 01/13/2011] [Indexed: 11/24/2022]
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19
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Hawe A, Rispens T, Herron JN, Jiskoot W. Probing bis-ANS Binding Sites of Different Affinity on Aggregated IgG by Steady-State Fluorescence, Time-Resolved Fluorescence and Isothermal Titration Calorimetry. J Pharm Sci 2011; 100:1294-305. [DOI: 10.1002/jps.22368] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/13/2010] [Accepted: 09/16/2010] [Indexed: 11/09/2022]
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20
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FtsZ in bacterial cytokinesis: cytoskeleton and force generator all in one. Microbiol Mol Biol Rev 2011; 74:504-28. [PMID: 21119015 DOI: 10.1128/mmbr.00021-10] [Citation(s) in RCA: 460] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
FtsZ, a bacterial homolog of tubulin, is well established as forming the cytoskeletal framework for the cytokinetic ring. Recent work has shown that purified FtsZ, in the absence of any other division proteins, can assemble Z rings when incorporated inside tubular liposomes. Moreover, these artificial Z rings can generate a constriction force, demonstrating that FtsZ is its own force generator. Here we review light microscope observations of how Z rings assemble in bacteria. Assembly begins with long-pitch helices that condense into the Z ring. Once formed, the Z ring can transition to short-pitch helices that are suggestive of its structure. FtsZ assembles in vitro into short protofilaments that are ∼30 subunits long. We present models for how these protofilaments might be further assembled into the Z ring. We discuss recent experiments on assembly dynamics of FtsZ in vitro, with particular attention to how two regulatory proteins, SulA and MinC, inhibit assembly. Recent efforts to develop antibacterial drugs that target FtsZ are reviewed. Finally, we discuss evidence of how FtsZ generates a constriction force: by protofilament bending into a curved conformation.
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21
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Banerjee PR, Pande A, Patrosz J, Thurston GM, Pande J. Cataract-associated mutant E107A of human gammaD-crystallin shows increased attraction to alpha-crystallin and enhanced light scattering. Proc Natl Acad Sci U S A 2011; 108:574-9. [PMID: 21173272 PMCID: PMC3021023 DOI: 10.1073/pnas.1014653107] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several point mutations in human γD-crystallin (HGD) are now known to be associated with cataract. So far, the in vitro studies of individual mutants of HGD alone have been sufficient in providing plausible molecular mechanisms for the associated cataract in vivo. Nearly all the mutant proteins in solution showed compromised solubility and enhanced light scattering due to altered homologous γ-γ crystallin interactions. In sharp contrast, here we present an intriguing case of a human nuclear cataract-associated mutant of HGD--namely Glu107 to Ala (E107A), which is nearly identical to the wild type in structure, stability, and solubility properties, with one exception: Its pI is higher by nearly one pH unit. This increase dramatically alters its interaction with α-crystallin. There is a striking difference in the liquid-liquid phase separation behavior of E107A-α-crystallin mixtures compared to HGD-α-crystallin mixtures, and the light-scattering intensities are significantly higher for the former. The data show that the two coexisting phases in the E107A-α mixtures differ much more in protein density than those that occur in HGD-α mixtures, as the proportion of α-crystallin approaches that in the lens nucleus. Thus in HGD-α mixtures, the demixing of phases occurs primarily by protein type while in E107A-α mixtures it is increasingly governed by protein density. Analysis of these results suggests that the cataract due to the E107A mutation could result from the instability caused by the altered attractive interactions between dissimilar proteins--i.e., heterologous γ-α crystallin interactions--primarily due to the change in surface electrostatic potential in the mutant protein.
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Affiliation(s)
| | | | - Julita Patrosz
- Department of Biology, University at Albany, State University of New York, Albany, NY 12222; and
| | - George M. Thurston
- Department of Physics, Rochester Institute of Technology, Rochester, NY 14623
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22
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Pande A, Ghosh KS, Banerjee PR, Pande J. Increase in surface hydrophobicity of the cataract-associated P23T mutant of human gammaD-crystallin is responsible for its dramatically lower, retrograde solubility. Biochemistry 2010; 49:6122-9. [PMID: 20553008 DOI: 10.1021/bi100664s] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cataract-associated Pro23 to Thr (P23T) mutation in human gammaD-crystallin (HGD) has a variety of phenotypes and is geographically widespread. Therefore, there is considerable interest in understanding the molecular basis of cataract formation due to this mutation. We showed earlier [Pande, A., et al. (2005) Biochemistry 44, 2491-2500] that the probable basis of opacity in this case is the severely compromised, retrograde solubility and aggregation of P23T relative to HGD. The dramatic solubility change occurs even as the structure of the mutant protein remains essentially unchanged in vitro. We proposed that the retrograde solubility and aggregation of P23T were mediated by net hydrophobic, protein-protein interactions. On the basis of these initial findings for P23T and related mutants, and the subsequent finding that they show atypical phase behavior [McManus, J. J., et al. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 16856-16861], we concluded that the protein clusters formed in solutions of the mutant proteins were held together by net hydrophobic, anisotropic interactions. Here we show, using chemical probes, that the surface hydrophobicities of these mutants are inversely related to their solubility. Furthermore, by probing the isolated N-terminal domains of HGD and P23T directly, we find that the increase in the surface hydrophobicity of P23T is localized in the N-terminal domain. Modeling studies suggest the presence of sticky patches on the surface of the N-terminal domain that could be engaged in the formation of protein clusters via hydrophobic protein-protein interactions. This work thus provides direct evidence of the dominant role played by net hydrophobic and anisotropic protein-protein interactions in the aggregation of P23T.
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Affiliation(s)
- Ajay Pande
- Department of Chemistry, Life Sciences Research Building, University at Albany, State University of New York, Albany, New York 12222, USA
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23
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Hawe A, Poole R, Jiskoot W. Misconceptions over Förster resonance energy transfer between proteins and ANS/bis-ANS: Direct excitation dominates dye fluorescence. Anal Biochem 2010; 401:99-106. [PMID: 20197057 DOI: 10.1016/j.ab.2010.02.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Revised: 02/23/2010] [Accepted: 02/25/2010] [Indexed: 11/30/2022]
Abstract
Our aim was to disprove the widespread misconception that Förster resonance energy transfer (FRET) is the only explanation for observing fluorescence from ANS (8-anilino-1-naphthalenesulfonic acid) and bis-ANS (4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid, dipotassium salt) following excitation at 280nm in the presence of protein. From ultraviolet (UV) absorption spectra and fluorescence emission spectra of bis-ANS and ANS in buffer and ethanol, direct excitation at 280nm was found to be the dominant mechanism for the resulting dye fluorescence. Furthermore, Tyr/Trp quenching studies were performed for solutions of N-acetyl-l-tryptophanamide, heat-stressed immunoglobulin G (IgG), and bovine serum albumin (BSA) by monitoring changes in steady state fluorescence spectra and time-resolved fluorescence decays as a function of dye concentration. Stronger quenching of the intrinsic BSA and IgG fluorescence in steady state than in time-resolved fluorescence by bis-ANS and ANS pointed toward static quenching being the dominant mechanism in addition to dynamic quenching and/or FRET. In conclusion, one should consider the role of direct excitation of ANS and bis-ANS at 280nm to ensure a proper interpretation of fluorescence signals resulting from dye-protein interactions. When ANS or bis-ANS is to be used for protein characterization, we recommend selectively exciting the dyes at the higher absorption wavelength maximum (370 or 385nm, respectively).
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Affiliation(s)
- Andrea Hawe
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands.
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24
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Hawe A, Filipe V, Jiskoot W. Fluorescent molecular rotors as dyes to characterize polysorbate-containing IgG formulations. Pharm Res 2009; 27:314-26. [PMID: 20041280 PMCID: PMC2812426 DOI: 10.1007/s11095-009-0020-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 11/24/2009] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim was to evaluate fluorescent molecular rotors (DCVJ and CCVJ), which are mainly sensitive to viscosity, for the characterization of polysorbate-containing IgG formulations and compare them to the polarity-sensitive dyes ANS, Bis-ANS and Nile Red. METHODS IgG formulations with polysorbate 20 or 80 were stressed below the aggregation temperature and analyzed by steady-state and time-resolved fluorescence and by HP-SEC with UV and fluorescent dye detection (Bis-ANS and CCVJ). Furthermore, commercial protein preparations of therapeutic proteins (Enbrel 50 mg, Humira 40 mg and MabThera 100 mg) were aggregated accordingly and analyzed with CCVJ fluorescence and HP-SEC. RESULTS Contrarily to (Bis-)ANS and Nile Red, the molecular rotors DCVJ and CCVJ showed low background fluorescence in polysorbate-containing buffers. Time-resolved fluorescence experiments confirmed the steady-state fluorescence data. Both DCVJ and CCVJ showed enhanced fluorescence intensity for aggregated IgG formulations and were suitable for the characterization of polysorbate-containing IgG formulations in steady-state fluorescence and HP-SEC with dye detection (CCVJ). CCVJ was capable of detecting thermally induced aggregation in the commercial polysorbate-containing products Enbrel 50 mg, Humira 40 mg and MabThera 100 mg. CONCLUSION Fluorescent molecular rotors are suitable probes to detect aggregation in polysorbate-containing IgG formulations.
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Affiliation(s)
- Andrea Hawe
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
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25
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Clément MJ, Kuoch BT, Ha-Duong T, Joshi V, Hamon L, Toma F, Curmi PA, Savarin P. The Stathmin-Derived I19L Peptide Interacts with FtsZ and Alters Its Bundling. Biochemistry 2009; 48:9734-44. [DOI: 10.1021/bi900556a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marie-Jeanne Clément
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Boï-trinh Kuoch
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Tap Ha-Duong
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, UMR/UEVE 8587, Evry, 91025 France
| | - Vandana Joshi
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Loïc Hamon
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Flavio Toma
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Patrick A. Curmi
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Philippe Savarin
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
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26
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Jaiswal R, Panda D. Differential Assembly Properties of Escherichia coli FtsZ and Mycobacterium tuberculosis FtsZ: An Analysis Using Divalent Calcium. J Biochem 2009; 146:733-42. [DOI: 10.1093/jb/mvp120] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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27
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Hawe A, Sutter M, Jiskoot W. Extrinsic fluorescent dyes as tools for protein characterization. Pharm Res 2008; 25:1487-99. [PMID: 18172579 PMCID: PMC2440933 DOI: 10.1007/s11095-007-9516-9] [Citation(s) in RCA: 863] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 12/05/2007] [Indexed: 11/16/2022]
Abstract
Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization.
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Affiliation(s)
- Andrea Hawe
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marc Sutter
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- Novartis Pharma AG, WSJ-316.4.14, CH-4056 Basel, Switzerland
| | - Wim Jiskoot
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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28
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Jaiswal R, Panda D. Cysteine 155 plays an important role in the assembly of Mycobacterium tuberculosis FtsZ. Protein Sci 2008; 17:846-54. [PMID: 18436955 DOI: 10.1110/ps.083452008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The assembly of FtsZ plays an important role in bacterial cell division. Mycobacterium tuberculosis FtsZ (MtbFtsZ) has a single cysteine residue at position 155. We have investigated the role of the lone cysteine residue in the assembly of MtbFtsZ using different complimentary approaches, namely chemical modification by a thiol-specific reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) or a cysteine-chelating agent HgCl(2), and site-directed mutagenesis of the cysteine residue. HgCl(2) strongly reduced the polymerized mass of MtbFtsZ while it had no detectable effect on the polymerization of Escherichia coli FtsZ, which lacks a cysteine residue. HgCl(2) inhibited the protofilamentous assembly of MtbFtsZ and induced the aggregation of the protein. Further, HgCl(2) perturbed the secondary structure of MtbFtsZ and increased the binding of a hydrophobic probe 1-anilinonaphthalene-8-sulfonic acid (ANS) with MtbFtsZ, indicating that the binding of HgCl(2) altered the conformation of MtbFtsZ. Chemical modification of MtbFtsZ by DTNB also decreased the polymerized mass of MtbFtsZ. Further, the mutagenesis of Cys-155 to alanine caused a strong reduction in the assembly of MtbFtsZ. Under assembly conditions, the mutated protein formed aggregates instead of protofilaments. Far-UV CD spectroscopy and ANS binding suggested that the mutated MtbFtsZ has different conformation than that of the native MtbFtsZ. The effect of the mutation or chemical modification of Cys-155 on the MtbFtsZ assembly has been explained considering its location in the MtbFtsZ crystal structure. The results together suggest that the cysteine residue (Cys-155) of MtbFtsZ plays an important role in the assembly of MtbFtsZ into protofilaments.
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Affiliation(s)
- Richa Jaiswal
- School of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
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29
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Hawe A, Friess W, Sutter M, Jiskoot W. Online fluorescent dye detection method for the characterization of immunoglobulin G aggregation by size exclusion chromatography and asymmetrical flow field flow fractionation. Anal Biochem 2008; 378:115-22. [PMID: 18455994 DOI: 10.1016/j.ab.2008.03.050] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/27/2008] [Accepted: 03/27/2008] [Indexed: 11/25/2022]
Abstract
The aim of this study was to develop an online fluorescent dye detection method suitable for high-pressure size exclusion chromatography (HP-SEC) and asymmetrical flow field flow fractionation (AF4). The noncovalent extrinsic fluorescent dye 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (Bis-ANS) was added to the mobile phase or the sample, and the fluorescence emission at 488nm was recorded on excitation at 385nm. By combining HP-SEC and AF4 with online dye detection, it was possible to simultaneously detect heat-induced aggregation and structural changes of monomeric and aggregated immunoglobulin G (IgG); an increase in Bis-ANS fluorescence was observed in both the aggregate and monomer fractions. These structural changes of individual fractions, which were not detectable by online UV and multiangle laser light scattering (MALLS) or by stand-alone dynamic light scattering (DLS), intrinsic IgG fluorescence, and far-UV circular dichroism (CD), resulted in progressive aggregation on storage. The developed online fluorescent dye detection for HP-SEC or AF4 with Bis-ANS is a powerful method to detect both aggregation and structural changes of both monomeric and aggregated IgG in heat-stressed formulations.
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Affiliation(s)
- Andrea Hawe
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands.
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30
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Domadia PN, Bhunia A, Sivaraman J, Swarup S, Dasgupta D. Berberine targets assembly of Escherichia coli cell division protein FtsZ. Biochemistry 2008; 47:3225-34. [PMID: 18275156 DOI: 10.1021/bi7018546] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ever increasing problem of antibiotic resistance necessitates a search for new drug molecules that would target novel proteins in the prokaryotic system. FtsZ is one such target protein involved in the bacterial cell division machinery. In this study, we have shown that berberine, a natural plant alkaloid, targets Escherichia coli FtsZ, inhibits the assembly kinetics of the Z-ring, and perturbs cytokinesis. It also destabilizes FtsZ protofilaments and inhibits the FtsZ GTPase activity. Saturation transfer difference NMR spectroscopy of the FtsZ-berberine complex revealed that the dimethoxy groups, isoquinoline nucleus, and benzodioxolo ring of berberine are intimately involved in the interaction with FtsZ. Berberine perturbs the Z-ring morphology by disturbing its typical midcell localization and reduces the frequency of Z-rings per unit cell length to half. Berberine binds FtsZ with high affinity ( K D approximately 0.023 microM) and displaces bis-ANS, suggesting that it may bind FtsZ in a hydrophobic pocket. Isothermal titration calorimetry suggests that the FtsZ-berberine interaction occurs spontaneously and is enthalpy/entropy-driven. In silico molecular modeling suggests that the rearrangement of the side chains of the hydrophobic residues in the GTP binding pocket may facilitate the binding of the berberine to FtsZ and lead to inhibition of the association between FtsZ monomers. Together, these results clearly indicate the inhibitory role of berberine on the assembly function of FtsZ, establishing it as a novel FtsZ inhibitor that halts the first stage in bacterial cell division.
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Affiliation(s)
- Prerna N Domadia
- Department of Biochemistry, The Institute of Science, Mumbai 400 032, India
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31
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Santra MK, Panda D. Acid-induced loss of functional properties of bacterial cell division protein FtsZ: evidence for an alternative conformation at acidic pH. Proteins 2007; 67:177-88. [PMID: 17243150 DOI: 10.1002/prot.21178] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Several types of bacteria live in highly acidic environments. Since the assembly of FtsZ is important for bacterial cytokinesis, the effects of pH on the assembly and structural properties of FtsZ were examined. FtsZ retained GTP binding ability but lost GTPase activity at pH 2.5. In the presence of GTP, FtsZ formed protofilaments at pH 7 while it formed aggregates instead of protofilaments at pH 2.5, indicating that GTP hydrolysis is important for the assembly of FtsZ into protofilaments. Further, the acid-inactivated state of FtsZ recovered its structural and functional properties upon refolding at pH 7, indicating that the cellular functions of FtsZ may be restored after removal of the external stress. In addition, the affinity of 1-anilinonaphthalene-8-sulfonic acid (ANS) binding to FtsZ was found to be higher at pH 2.5 than at pH 7. FtsZ-ANS complex had a higher quantum yield and lifetime at pH 2.5 than at pH 7. However, the secondary structures of FtsZ were similar at pH 7 and 2.5, indicating that FtsZ attained an alternatively folded state (A) at pH 2.5, which has some characteristics of a molten-globule-like state. The A state was more stable than the native state (N) against urea-induced unfolding. The transition from N to A state involves the formation of aggregates of FtsZ (I). The association of FtsZ monomers occurred in the narrow pH range (3.2-2.8) and it was found to be a fully reversible process. The results suggest that a productive intermediate (I) forms in the acid-induced unfolding pathway of FtsZ and that the unfolding pathway may be minimally described as N <==> I <==> A.
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Affiliation(s)
- Manas K Santra
- The School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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32
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Santra MK, Dasgupta D, Panda D. Deuterium oxide promotes assembly and bundling of FtsZ protofilaments. Proteins 2005; 61:1101-10. [PMID: 16245323 DOI: 10.1002/prot.20671] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The assembly and bundling of FtsZ protofilaments play an important role during bacterial cell division. Deuterium oxide (D2O) is known to have strong stabilization effects on the assembly dynamics of several proteins including tubulin, a homologue of FtsZ. Here, we found that D2O enhanced the light-scattering intensity of the assembly reaction, increased sedimentable polymer mass, and induced bundling of FtsZ protofilaments. D2O also increased the stability of FtsZ polymers under challenged GTP conditions and suppressed dilution-induced disassembly of protofilaments. D2O enhances the assembly parameters of FtsZ and microtubules albeit differently. For example, D2O induced bundling of FtsZ protofilaments, whereas it did not induce bundling of microtubules in vitro. In addition, D2O strongly suppressed the GTP hydrolysis rate of microtubules, but it had no effect on the initial rate of GTP hydrolysis of the FtsZ assembly. D2O (80%) also increased the helical content of FtsZ by 25% compared to the helical content of FtsZ in aqueous buffer. D2O was shown to reduce the binding of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) to tubulin. In contrast, we found that D2O strongly enhanced the binding of bis-ANS to FtsZ. The results indicated that D2O promotes assembly and bundling of FtsZ protofilaments by increasing hydrophobic interactions between the protofilaments. The results also suggest that the phosphate release rather than the on-site GTP hydrolysis is the rate-limiting step of the GTP turnover reaction.
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Affiliation(s)
- Manas Kumar Santra
- School of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai, India
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33
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Santra MK, Panda D. Detection of an intermediate during unfolding of bacterial cell division protein FtsZ: loss of functional properties precedes the global unfolding of FtsZ. J Biol Chem 2003; 278:21336-43. [PMID: 12649276 DOI: 10.1074/jbc.m301303200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Using environment-sensitive fluorescence of 1-anilinonaphthalene-8-sulfonic acid, polarization of fluorescein 5'-isothiocyanate-labeled FtsZ, and far-UV circular dichroism spectroscopy, the chemical unfolding of FtsZ was found to proceed through two steps. The first step of the urea-induced unfolding produced an intermediate, which then unfolded at higher concentrations of urea. The intermediate state contains native-like secondary structure and much less tertiary structure compared with the native state. It is distinct from the native state as well as from the unfolded state. Similar to urea-induced unfolding of FtsZ, thermal unfolding of FtsZ also occurs in two steps. The midpoints for the first and second thermal unfolding transitions were found to be 38 +/- 4 and 77 +/- 5 degrees C, respectively. Further, the functional properties of FtsZ are extremely sensitive to urea, guanidium chloride, and sodium dodecyl sulfate. For example, 50% inhibition of the FtsZ assembly and GTP hydrolysis occurred at 0.1 and 0.2 m of urea, respectively. FtsZ lost its functional properties before any significant perturbation in the secondary or tertiary structure was detected by using several fluorescence techniques and far UV-CD indicating preferential local unfolding of the functional region(s). In addition, the unfolded FtsZ regains its ability to polymerize fully upon removal of urea. The data taken together suggest that FtsZ unfolds reversibly through a multistep process, and local responses that inhibit functional properties precede the global transition of FtsZ to the unfolded state.
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Affiliation(s)
- Manas K Santra
- School of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India
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Beuria TK, Krishnakumar SS, Sahar S, Singh N, Gupta K, Meshram M, Panda D. Glutamate-induced assembly of bacterial cell division protein FtsZ. J Biol Chem 2003; 278:3735-41. [PMID: 12446699 DOI: 10.1074/jbc.m205760200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The polymerization of FtsZ is a finely regulated process that plays an essential role in the bacterial cell division process. However, only a few modulators of FtsZ polymerization are known. We identified monosodium glutamate as a potent inducer of FtsZ polymerization. In the presence of GTP, glutamate enhanced the rate and extent of polymerization of FtsZ in a concentration-dependent manner; approximately 90% of the protein was sedimented as polymer in the presence of 1 m glutamate. Electron micrographs of glutamate-induced polymers showed large filamentous structures with extensive bundling. Furthermore, glutamate strongly stabilized the polymers against dilution-induced disassembly, and it decreased the GTPase activity of FtsZ. Calcium induced FtsZ polymerization and bundling of FtsZ polymers; interestingly, although 1 m glutamate produced a larger light-scattering signal than produced by 10 mm calcium, the amount of polymer sedimented in the presence of 1 m glutamate and 10 mm calcium was similar. Thus, the increased light scattering in the presence of glutamate must be due to its ability to induce more extensive bundling of FtsZ polymers than calcium. The data suggest that calcium and glutamate might induce FtsZ polymerization by different mechanisms.
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Affiliation(s)
- Tushar K Beuria
- School of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India
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35
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Gupta S, Chakraborty S, Poddar A, Sarkar N, Das KP, Bhattacharyya B. BisANS binding to tubulin: isothermal titration calorimetry and the site-specific proteolysis reveal the GTP-induced structural stability of tubulin. Proteins 2003; 50:283-9. [PMID: 12486722 DOI: 10.1002/prot.10292] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Interactions of bisANS and ANS to tubulin in the presence and absence of GTP were investigated, and the binding and thermodynamic parameters were determined using isothermal titration calorimetry. Like bisANS binding to tubulin, we observed a large number of lower affinity ANS binding sites (N1 = 1.3, K1 = 3.7 x 10(5) M(-1), N2 = 10.5, K2 = 7 x 10(4)/M(-1)) in addition to 1-2 higher affinity sites. Although the presence of GTP lowers the bisANS binding to both higher and lower affinity sites (N1 = 4.3, N2 = 11.7 in absence and N1 = 1.8, N2 = 3.6 in presence of GTP), the stoichiometries of both higher and lower affinity sites of ANS remain unaffected in the presence of GTP. BisANS-induced structural changes on tubulin were studied using site-specific proteolysis with trypsin and chymotrypsin. Digestion of both alpha and beta tubulin with trypsin and chymotrypsin, respectively, has been found to be very specific in presence of GTP. GTP has dramatic effects on lowering the extent of nonspecific digestion of beta tubulin with trypsin and stabilizing the intermediate bands produced from both alpha and beta. BisANS-treated tubulin is more susceptible to both trypsin and chymotrypsin digestion. At higher bisANS concentration (>20 microM) both alpha and beta tubulins are almost totally digested with enzymes, indicating bisANS-induced unfolding or destabilization of tubulin structure. Again, the addition of GTP has remarkable effect on lowering the bisANS-induced enhanced digestion of tubulin as well as stabilizing effect on intermediate bands. These results of isothermal titration calorimetry, proteolysis and the DTNB-kinetics data clearly established that the addition of GTP makes tubulin compact and rigid and hence the GTP-induced stabilization of tubulin structure. No such destabilization of tubulin structure has been noticed with ANS, although, like bisANS, ANS possesses a large number of lower affinity binding sites. On the basis of these results, we propose that the unique structure of bisANS, which in absence of GTP can bind tubulin as a bifunctional ligand (through its two ANS moieties), is responsible for the structural changes of tubulin.
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Affiliation(s)
- Suvroma Gupta
- Department of Biochemistry, Bose Institute, Centenary Campus, Calcutta, India
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36
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Bobrovnik SA. Ligand-receptor interactions: a new method for determining the binding parameters. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 2003; 55:71-86. [PMID: 12559590 DOI: 10.1016/s0165-022x(02)00179-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new experimental procedure and new plot coordinates that allow determination of the binding parameters of ligand-acceptor interaction have been proposed. Instead of titration of a constant concentration of receptors with changing concentrations of ligand, as requested by the well-known methods of Klotz and Scatchard, a series of sequential dilutions of the reacting ligand-receptor mixture is suggested. This allows the application of a new coordinate system that transforms the binding isotherms into straight lines. The case of one acceptor with two classes of receptors with different binding constants is also considered briefly, where the correspondent graphs are nonlinear. It is suggested that in some cases this approach can be a simple and convenient substitute of the broadly used methods of Klotz and Scatchard.
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Affiliation(s)
- S A Bobrovnik
- Department of Molecular Immunology, Palladin Institute of Biochemistry, Kiev 01030, Ukraine.
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37
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LeVine H. 4,4(')-Dianilino-1,1(')-binaphthyl-5,5(')-disulfonate: report on non-beta-sheet conformers of Alzheimer's peptide beta(1-40). Arch Biochem Biophys 2002; 404:106-15. [PMID: 12127075 DOI: 10.1016/s0003-9861(02)00246-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The venerable fluorescent probe of protein hydrophobic regions, 4,4(')-dianilino-1,1(')-binaphthyl-5,5(')-disulfonate (bis-ANS), unexpectedly increases in fluorescence with soluble beta(1-40) in acidic buffer solutions but reacts weakly with amyloid fibrils while other hydrophobic probes react with the fibrils. CD analysis correlates reaction with the probe with random coil/mixed conformations and alpha-helical forms of beta(1-40) in buffer solutions but less so with soluble beta-sheet forms or amyloid fibrils. The kinetics of the fluoroalcohol-induced interconversion of conformers can be followed by changes in bis-ANS fluorescence. Formation of the beta-sheet form in aqueous buffer is limited by a slow component (minutes) while fluoroalcohol-promoted changes between beta-sheet and alpha-helix occur over seconds. Variants of beta(1-40) such as beta(1-42) or the Dutch E22Q mutation of beta(1-40) and fragments beta(1-28), beta(12-28), beta(10-20 amide), and beta(10-35 amide) react with bis-ANS under conditions that do not support fibril formation. Primary amino acid sequence is important as beta(1-11) does not cause bis-ANS fluorescence while beta(1-16) does, but hydrophobicity is not as beta(25-35) and beta(15-20 amide) are unreactive. bis-ANS is a useful biophysical tool for characterizing particular, but not all, soluble Abeta conformations distinct from the fibrillar form of amyloid peptides detected by Thioflavin T.
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Affiliation(s)
- Harry LeVine
- CNS Pharmacology, Pfizer Global Research and Development, Ann Arbor, MI 48105, USA.
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38
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Wallis DD, Tan FK, Kielty CM, Kimball MD, Arnett FC, Milewicz DM. Abnormalities in fibrillin 1-containing microfibrils in dermal fibroblast cultures from patients with systemic sclerosis (scleroderma). ARTHRITIS AND RHEUMATISM 2001; 44:1855-64. [PMID: 11508439 DOI: 10.1002/1529-0131(200108)44:8<1855::aid-art324>3.0.co;2-q] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To determine if there are abnormalities in fibrillin 1-containing microfibrils in the extracellular matrix (ECM) of primary dermal fibroblasts explanted from patients with systemic sclerosis (SSc). METHODS Explanted fibroblasts from unaffected skin of 12 SSc patients were used to examine fibrillin 1-containing microfibrils by immunofluorescence (IF) using a monoclonal antibody (mAb) to fibrillin 1. Metabolic labeling of the fibroblast cultures was used to study the synthesis, secretion, and processing of fibrillin 1, as well as to observe microfibril formation and stability. Microfibrils elaborated by the SSc cells were analyzed by electron microscopy for ultrastructural abnormalities, and the results were confirmed by immunoblotting. RESULTS Control and SSc fibroblasts displayed a prominent meshwork of fibrillin 1-containing microfibrils when visualized by IF using a fibrillin 1 mAb. Paradoxically, metabolic studies indicated a paucity of fibrillin 1 in the ECM in the majority of the SSc fibroblast strains. Subsequent rotary-shadowed electron microscopy revealed reduced amounts of and ultrastructural abnormalities in the microfibrils elaborated by all strains of SSc cells. Immunoblots confirmed the lack of the high molecular weight form of fibrillin 1 in the SSc fibroblasts of Choctaw American Indians. Finally, in vitro studies indicated that the amount of fibrillin 1 in the ECM of SSc cells diminished at a faster rate than the amount of fibrillin 1 in the ECM of control cells with time. CONCLUSION Although SSc fibroblasts assemble microfibrils, these microfibrils are unstable, suggesting that an inherent defect of fibrillin 1-containing microfibrils may play a role in the pathogenesis of SSc.
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Affiliation(s)
- D D Wallis
- University of Texas-Houston Medical School, 77030, USA
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39
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Karapitta CD, Xenakis A, Papadimitriou A, Sotiroudis TG. A new homogeneous enzyme immunoassay for thyroxine using glycogen phosphorylase b-thyroxine conjugates. Clin Chim Acta 2001; 308:99-106. [PMID: 11412821 DOI: 10.1016/s0009-8981(01)00469-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND [corrected] Measurement of serum thyroxine (T(4)) concentration is important for diagnosis of thyroid gland diseases. We developed a practical homogeneous enzyme immunoassay for thyroxine analysis in unextracted sera. METHODS A thyroxine derivative conjugated to a reactive sulfhydryl group of glycogen phosphorylase b (GPb). Conjugation caused inhibition of enzyme activity and the enzyme conjugate was re-activated upon the binding of a polyclonal anti-T(4) antibody. Antibody-activation was blocked by the presence of free T(4). RESULTS Conjugation affected the allosteric character of the enzyme and the K(m) for the allosteric activator AMP was increased 28 times, while anti-T(4) antibody partially reversed this effect. The optimum concentration ratio of enzyme conjugate to anti-T(4) antibody was determined, and T(4) was measured with desired sensitivity and accuracy in the range between 10 and 240 microg/l. Furosemide was used to inhibit the interaction of thyroxine with serum T(4)-binding sites. Human serum T(4) values obtained by this method correlated well with those obtained by a radioimmunoassay (y=1.9+1.0x, r=0.97, N=72). CONCLUSIONS Chemical modification of glycogen phosphorylase b with a T(4) derivative led to the development of a simple homogenous enzyme immunoassay for T(4) analysis with the desired sensitivity and accuracy.
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Affiliation(s)
- C D Karapitta
- Industrial Enzymology Unit, Institute of Biological Research and Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635, Athens, Greece
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40
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Karapitta CD, Sotiroudis TG, Papadimitriou A, Xenakis A. Homogeneous Enzyme Immunoassay for Triiodothyronine in Serum. Clin Chem 2001. [DOI: 10.1093/clinchem/47.3.569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AbstractBackground: The concentration of triiodothyronine (T3) in human serum is extremely low and can be determined only by very sensitive methods. We developed a homogeneous enzyme immunoassay for T3 analysis in unextracted serum.Methods: A T3 derivative was conjugated to the −SH groups of glycogen phosphorylase b (GPb) from rabbit muscle. Conjugation caused inhibition of enzyme activity, and the enzyme conjugate was reactivated upon binding of anti-T3 antibody. Activation was blocked by the presence of non-antibody-bound T3; this was the basis for the development of the homogeneous enzyme immunoassay for T3 by determining GPb activity fluorometrically.Results: We used furosemide to block the interaction of T3 with serum proteins with T3-binding sites, avoiding any serum treatment step. T3 was measured in the range 0.3–8 μg/L. T3 values obtained by this assay correlated well with those obtained by a RIA (y = 0.97x − 0.07 μg/L; r = 0.96; n = 92). Within- and between-run imprecision (CV) was 5–9% for normal and high concentrations and 16–20% for low concentrations.Conclusions: Chemical modification of GPb with a T3 derivative allows the development of a simple homogeneous enzyme immunoassay for T3 in unextracted serum.
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Affiliation(s)
- Christina D Karapitta
- Industrial Enzymology Unit, Institute of Biological Research & Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens, Greece
- MEDICON S.A., 15344 Gerakas, Greece
| | - Theodore G Sotiroudis
- Industrial Enzymology Unit, Institute of Biological Research & Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens, Greece
| | | | - Aristotelis Xenakis
- Industrial Enzymology Unit, Institute of Biological Research & Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens, Greece
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Abstract
The mechanism responsible for creating the division site in the right place at the right time in bacteria is unknown. It has been attributed to the formation of proteolipid domains in the cytoplasmic membrane surrounding the nucleoids. We interpret the growing evidence for this hypothesis by invoking hyperstructures, which exist at a level of organization intermediate between macromolecules and genes. Non-equilibrium hyperstructures comprise the genes, mRNA proteins and lipids required for a particular function such as cell division, and assemble and disassemble according to the needs of the cell.
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Affiliation(s)
- V Norris
- Laboratoire des Processus Intégratifs Cellulaires, UPRESA CNRS 6037, IFR 'Systèmes Intégrés', Faculté des Sciences et Techniques, Université de Rouen, 76821 cedex, Mont-Saint-Aignan, France.
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42
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Sarcina M, Mullineaux CW. Effects of tubulin assembly inhibitors on cell division in prokaryotes in vivo. FEMS Microbiol Lett 2000; 191:25-9. [PMID: 11004395 DOI: 10.1111/j.1574-6968.2000.tb09314.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The bacterial cell division protein FtsZ is a structural analogue of tubulin. Bacterial mutants in which the ftsZ gene is inactivated are unable to divide. Numerous inhibitors of tubulin assembly are known, some of which are used as fungicides. The strong structural homology between FtsZ and tubulin raises the possibility that some of these inhibitors could affect bacterial cell division. Here we report that the tubulin assembly inhibitors thiabendazole and 2-methylbenzimidazole cause cell elongation in Escherichia coli and cyanobacteria.
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Affiliation(s)
- M Sarcina
- Department of Biology, University College London, Darwin Building, Gower St., WC1E 6BT, London, UK
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43
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Abstract
Perhaps the biggest single task facing a bacterial cell is to divide into daughter cells that contain the normal complement of chromosomes. Recent technical and conceptual breakthroughs in bacterial cell biology, combined with the flood of genome sequence information and the excellent genetic tools in several model systems, have shed new light on the mechanism of prokaryotic cell division. There is good evidence that in most species, a molecular machine, organized by the tubulin-like FtsZ protein, assembles at the site of division and orchestrates the splitting of the cell. The determinants that target the machine to the right place at the right time are beginning to be understood in the model systems, but it is still a mystery how the machine actually generates the constrictive force necessary for cytokinesis. Moreover, although some cell division determinants such as FtsZ are present in a broad spectrum of prokaryotic species, the lack of FtsZ in some species and different profiles of cell division proteins in different families suggests that there are diverse mechanisms for regulating cell division.
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Affiliation(s)
- W Margolin
- Department of Microbiology and Molecular Genetics, University of Texas-Houston Medical School, 6431 Fannin, Houston, Texas 77030, USA.
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44
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Seong IS, Oh JY, Lee JW, Tanaka K, Chung CH. The HslU ATPase acts as a molecular chaperone in prevention of aggregation of SulA, an inhibitor of cell division in Escherichia coli. FEBS Lett 2000; 477:224-9. [PMID: 10908725 DOI: 10.1016/s0014-5793(00)01808-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
HslVU is an ATP-dependent protease consisting of two multimeric components: the HslU ATPase and the HslV peptidase. SulA, which is an inhibitor of cell division and has high tendency of aggregation, is degraded by HslVU protease. Here we show that HslU plays a role not only as a regulatory component for the HslV-mediated proteolysis but also as a molecular chaperone. Purified HslU prevented aggregation of SulA in a concentration-dependent fashion. This chaperone activity required oligomerization of HslU subunits, which could be achieved by ATP-binding or in the presence of high HslU protein concentrations. hsl mutation reduced the SulA-mediated inhibition of cell growth and this effect could be reversed upon overproduction of HslU, suggesting that HslU promotes the ability of SulA to block cell growth through its chaperone function. Thus, HslU appears to have two antagonistic functions: one as a chaperone for promotion of the ability of SulA in cell growth inhibition by preventing SulA aggregation and the other as the regulatory component for elimination of SulA by supporting the HslV-mediated degradation.
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Affiliation(s)
- I S Seong
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea
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45
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Scheffers DJ, den Blaauwen T, Driessen AJ. Non-hydrolysable GTP-gamma-S stabilizes the FtsZ polymer in a GDP-bound state. Mol Microbiol 2000; 35:1211-9. [PMID: 10712701 DOI: 10.1046/j.1365-2958.2000.01791.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
FtsZ, a tubulin homologue, forms a cytokinetic ring at the site of cell division in prokaryotes. The ring is thought to consist of polymers that assemble in a strictly GTP-dependent way. GTP, but not guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S), has been shown to induce polymerization of FtsZ, whereas in vitro Ca2+ is known to inhibit the GTP hydrolysis activity of FtsZ. We have studied FtsZ dynamics at limiting GTP concentrations in the presence of 10 mM Ca2+. GTP and its non-hydrolysable analogue GTP-gamma-S bind FtsZ with similar affinity, whereas the non-hydrolysable analogue guanylyl-imidodiphosphate (GMP-PNP) is a poor substrate. Preformed FtsZ polymers can be stabilized by GTP-gamma-S and are destabilized by GDP. As more than 95% of the nucleotide associated with the FtsZ polymer is in the GDP form, it is concluded that GTP hydrolysis by itself does not trigger FtsZ polymer disassembly. Strikingly, GTP-gamma-S exchanges only a small portion of the FtsZ polymer-bound GDP. These data suggest that FtsZ polymers are stabilized by a small fraction of GTP-containing FtsZ subunits. These subunits may be located either throughout the polymer or at the polymer ends, forming a GTP cap similar to tubulin.
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Affiliation(s)
- D J Scheffers
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
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46
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Ma X, Margolin W. Genetic and functional analyses of the conserved C-terminal core domain of Escherichia coli FtsZ. J Bacteriol 1999; 181:7531-44. [PMID: 10601211 PMCID: PMC94211 DOI: 10.1128/jb.181.24.7531-7544.1999] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, FtsZ is required for the recruitment of the essential cell division proteins FtsA and ZipA to the septal ring. Several C-terminal deletions of E. coli FtsZ, including one of only 12 amino acids that removes the highly conserved C-terminal core domain, failed to complement chromosomal ftsZ mutants when expressed on a plasmid. To identify key individual residues within the core domain, six highly conserved residues were replaced with alanines. All but one of these mutants (D373A) failed to complement an ftsZ chromosomal mutant. Immunoblot analysis demonstrated that whereas I374A and F377A proteins were unstable in the cell, L372A, D373A, P375A, and L378A proteins were synthesized at normal levels, suggesting that they were specifically defective in some aspect of FtsZ function. In addition, all four of the stable mutant proteins were able to localize and form rings at potential division sites in chromosomal ftsZ mutants, implying a defect in a function other than localization and multimerization. Because another proposed function of FtsZ is the recruitment of FtsA and ZipA, we tested whether the C-terminal core domain was important for interactions with these proteins. Using two different in vivo assays, we found that the 12-amino-acid truncation of FtsZ was defective in binding to FtsA. Furthermore, two point mutants in this region (L372A and P375A) showed weakened binding to FtsA. In contrast, ZipA was capable of binding to all four stable point mutants in the FtsZ C-terminal core but not to the 12-amino-acid deletion.
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Affiliation(s)
- X Ma
- Department of Microbiology and Molecular Genetics, University of Texas- Houston Medical School, Houston, Texas 77030, USA
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47
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Yu XC, Margolin W, Gonzalez-Garay ML, Cabral F. Vinblastine induces an interaction between FtsZ and tubulin in mammalian cells. J Cell Sci 1999; 112 ( Pt 14):2301-11. [PMID: 10381386 DOI: 10.1242/jcs.112.14.2301] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Escherichia coli cell division protein FtsZ was expressed in Chinese hamster ovary cells, where it formed a striking array of dots that were independent of the mammalian cytoskeleton. Although FtsZ appears to be a bacterial homolog of tubulin, its expression had no detectable effects on the microtubule network or cell growth. However, treatment of the cells with vinblastine at concentrations that caused microtubule disassembly rapidly induced a network of FtsZ filaments that grew from and connected the dots, suggesting that the dots are an active storage form of FtsZ. Cells producing FtsZ also exhibited vinblastine- and calcium-resistant tubulin polymers that colocalized with the FtsZ network. The FtsZ polymers could be selectively disassembled, indicating that the two proteins were not copolymerized. The vinblastine effects were readily reversible by washing out the drug or by treating the cells with the vinblastine competitor, maytansine. These results demonstrate that FtsZ assembly can occur in the absence of bacterial chaperones or cofactors, that FtsZ and tubulin do not copolymerize, and that tubulin-vinblastine complexes have an enhanced ability to interact with FtsZ.
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Affiliation(s)
- X C Yu
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030, USA
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48
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Chakraborty S, Sarkar N, Bhattacharyya B. Nucleotide-dependent bisANS binding to tubulin. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1432:350-5. [PMID: 10407156 DOI: 10.1016/s0167-4838(99)00110-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Non-covalent hydrophobic probes such as 5, 5'-bis(8-anilino-1-naphthalenesulfonate) (bisANS) have become increasingly popular to gain information about protein structure and conformation. However, there are limitations as bisANS binds non-specifically at multiple sites of many proteins. Successful use of this probe depends upon the development of binding conditions where only specific dye-protein interaction will occur. In this report, we have shown that the binding of bisANS to tubulin occurs instantaneously, specifically at one high affinity site when 1 mM guanosine 5'-triphosphate (GTP) is included in the reaction medium. Substantial portions of protein secondary structure and colchicine binding activity of tubulin are lost upon bisANS binding in absence of GTP. BisANS binding increases with time and occurs at multiple sites in the absence of GTP. Like GTP, other analogs, guanosine 5'-diphosphate, guanosine 5'-monophosphate and adenosine 5'-triphosphate, also displace bisANS from the lower affinity sites of tubulin. We believe that these multiple binding sites are generated due to the bisANS-induced structural changes on tubulin and the presence of GTP and other nucleotides protect those structural changes.
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Affiliation(s)
- S Chakraborty
- Department of Biochemistry, Bose Institute, Centenary Building, P-1/12 C.I.T. Scheme VII M, Calcutta 700054, India
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49
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Sun Q, Yu XC, Margolin W. Assembly of the FtsZ ring at the central division site in the absence of the chromosome. Mol Microbiol 1998; 29:491-503. [PMID: 9720867 DOI: 10.1046/j.1365-2958.1998.00942.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The FtsZ ring assembles between segregated daughter chromosomes in prokaryotic cells and is essential for cell division. To understand better how the FtsZ ring is influenced by chromosome positioning and structure in Escherichia coli, we investigated its localization in parC and mukB mutants that are defective for chromosome segregation. Cells of both mutants at non-permissive temperatures were either filamentous with unsegregated nucleoids or short and anucleate. In parC filaments, FtsZ rings tended to localize only to either side of the central unsegregated nucleoid and rarely to the cell midpoint; however, medial rings reappeared soon after switching back to the permissive temperature. Filamentous mukB cells were usually longer and lacked many potential rings. At temperatures permissive for mukB viability, medial FtsZ rings assembled despite the presence of apparently unsegregated nucleoids. However, a significant proportion of these FtsZ rings were mislocalized or structurally abnormal. The most surprising result of this study was revealed upon further examination of FtsZ ring positioning in anucleate cells generated by the parC and mukB mutants: many of these cells, despite having no chromosome, possessed FtsZ rings at their midpoints. This discovery strongly suggests that the chromosome itself is not required for the proper positioning and development of the medial division site.
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Affiliation(s)
- Q Sun
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston 77030, USA
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