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Hajhosseini A, Sharifan A, Eftekhari Z, Alavi A, Doroud D. Optimal Extraction and Deproteinization Method for Mannoprotein Purification from Kluyveromyces marxianus. Iran Biomed J 2023; 27:320-25. [PMID: 37525429 DOI: 10.52547/ibj.3200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Background Mannoproteins, mannose-glycosylated proteins, play an important role in biological processes and have various applications in industries. Several methods have been already used for the extraction of mannoproteins from yeast cell-wall. The aim of this study was to evaluate the extraction and deproteinization of mannan oligosaccharide from the Kluyveromyces (K.) marxianus mannoprotein. Methods To acquire crude mannan oligosaccharides, K. marxianus mannoproteins were deproteinized by the Sevage, trichloroacetic acid, and hydrochloric acid (HCL) methods. Total nitrogen, crude protein content, fat, carbohydrate and ash content were measured according to the monograph prepared by the meeting of the Joint FAO/WHO Expert Committee and standard. Mannan oligosaccharide loss, percentage of deproteinization, and chemical composition of the product were assessed to check the proficiency of different methods. Results Highly purified (95.4%) mannan oligosaccharide with the highest deproteinization (97.33 ± 0.4%) and mannan oligosaccharide loss (25.1 ± 0.6%) were obtained following HCl method. Conclusion HCl, was the most appropriate deproteinization method for the removal of impurities. This preliminary data will support future studies to design scale-up procedures.
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Affiliation(s)
| | - Anousheh Sharifan
- Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Zohreh Eftekhari
- Biotechnology Department, Pasteur Institute of Iran, Tehran, Iran
| | - Ariana Alavi
- Biotechnology Department, Pasteur Institute of Iran, Tehran, Iran
| | - Delaram Doroud
- Biotechnology Department, Pasteur Institute of Iran, Tehran, Iran
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Hajhosseini A, Sharifan A, Eftekhari Z, Alavi A, Doroud D. Optimal Extraction and Deproteinization Method for Mannoprotein Purification from Kluyveromyces marxianus. Iran Biomed J 2023; 27:320-25. [PMID: 37525429 PMCID: PMC10707814 DOI: 10.61186/ibj.27.5.320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 02/09/2023] [Indexed: 12/17/2023]
Abstract
Background Mannoproteins, mannose-glycosylated proteins, play an important role in biological processes and have various applications in industries. Several methods have been already used for the extraction of mannoproteins from yeast cell-wall. The aim of this study was to evaluate the extraction and deproteinization of mannan oligosaccharide from the Kluyveromyces (K.) marxianus mannoprotein. Methods To acquire crude mannan oligosaccharides, K. marxianus mannoproteins were deproteinized by the Sevage, trichloroacetic acid, and hydrochloric acid (HCL) methods. Total nitrogen, crude protein content, fat, carbohydrate and ash content were measured according to the monograph prepared by the meeting of the Joint FAO/WHO Expert Committee and standard. Mannan oligosaccharide loss, percentage of deproteinization, and chemical composition of the product were assessed to check the proficiency of different methods. Results Highly purified (95.4%) mannan oligosaccharide with the highest deproteinization (97.33 ± 0.4%) and mannan oligosaccharide loss (25.1 ± 0.6%) were obtained following HCl method. Conclusion HCl, was the most appropriate deproteinization method for the removal of impurities. This preliminary data will support future studies to design scale-up procedures.
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Affiliation(s)
- Ashraf Hajhosseini
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Anousheh Sharifan
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Zohre Eftekhari
- Biotechnology Department, Pasteur Institute of Iran, Tehran, Iran
| | - Ariana Alavi
- Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran
| | - Delaram Doroud
- Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran
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Wang CH, Xiong WP, Huang C, Li XM, Wang QY, Huang RB. Engineering better catalytic activity and acidic adaptation into Kluyveromyces marxianus exoinulinase using site-directed mutagenesis. J Sci Food Agric 2021; 101:2472-2482. [PMID: 33034040 DOI: 10.1002/jsfa.10873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 10/03/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Exoinulinase catalyzes the successive removal of individual fructose moiety from the non-reducing end of the inulin molecule, which is useful for biotechnological applications like producing fructan-based non-grain biomass energy and high-fructose syrup. In this study, an exoinulinase (KmINU) from Kluyveromyces marxianus DSM 5418 was tailored for increased catalytic activity and acidic adaptation for inulin hydrolysis processes by rational site-directed mutagenesis. RESULTS Three mutations, S124Y, N158S and Q215V distal to the catalytic residues of KmINU were designed and heterologously expressed in Pichia pastoris GS115. Compared to the wild-type, S124Y shifted the pH-activity profile towards acidic pH values and increased the catalytic activity and catalytic efficiency by 59% and 99% to 688.4 ± 17.03 s-1 and 568.93 L mmol-1 s-1 , respectively. N158S improved the catalytic activity under acidic pH conditions, giving a maximum value of 464.06 ± 14.06 s-1 on inulin at pH 4.5. Q215V markedly improved the substrate preference for inulin over sucrose by 5.56-fold, and showed catalytic efficiencies of 208.82 and 6.88 L mmol-1 s-1 towards inulin and sucrose, respectively. Molecular modeling and computational docking indicated that structural reorientation may underlie the increased catalytic activity, acidic adaptation and substrate preference. CONCLUSIONS The KmINU mutants may serve as industrially promising candidates for inulin hydrolysis. Protein engineering of exoinulinase here provides a successful example of the extent to which mutating non-conserved substrate recognition and binding residues distal to the active site can be used for industrial enzyme improvements. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Cheng-Hua Wang
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Wu-Ping Xiong
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Cheng Huang
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Xiao-Ming Li
- Nanning Sinozyme Biotechnology Co., Ltd, Nanning, China
| | - Qing-Yan Wang
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning, China
| | - Ri-Bo Huang
- College of Life Science and Technology, Guangxi University, Nanning, China
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning, China
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Nolan V, Collin A, Rodriguez C, Perillo MA. Effect of Polyethylene Glycol-Induced Molecular Crowding on the Enzymatic Activity and Thermal Stability of β-Galactosidase from Kluyveromyces lactis. J Agric Food Chem 2020; 68:8875-8882. [PMID: 32686401 DOI: 10.1021/acs.jafc.0c02316] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Here, we report the effect of polyethylene glycol (PEG6000)-induced molecular crowding (MC) on the catalytic activity and thermal stability of Kluyveromyces lactis β-galactosidase (β-Gal). The β-Gal-catalyzed hydrolysis of o-nitrophenyl-β-d-galactopyranoside followed a Michaelian kinetics at [PEG6000] ≤ 25% w/v and positive cooperativity at higher concentrations (35% w/v PEG6000). Compared with dilute solutions, in the MC media, β-Gal exhibited stronger thermal stability, as shown by the increase in the residual activity recovered after preincubation at high temperatures (e.g., 45 °C) and by the slower inactivation kinetics. Considering the effects of water thermodynamic activity on the reaction kinetics and protein structure and the effect of the exclusion volume on protein conformation, we suggest that changes in the protein oligomerization state and hydration could be the responsible for the behavior observed at the highest MC levels assayed. These results could be relevant and should be taken into account in industrial food processes applying β-Gal from K. lactis.
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Affiliation(s)
- Verónica Nolan
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Fı́sicas y Naturales. ICTA and Departamento de Quı́mica, Cátedra de Quı́mica Biológica, Avenue Vélez Sársfield 1611, 5016 Córdoba, Argentina
- CONICET-Universidad Nacional de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), 5016 Córdoba, Argentina
| | - Alejandro Collin
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Fı́sicas y Naturales. ICTA and Departamento de Quı́mica, Cátedra de Quı́mica Biológica, Avenue Vélez Sársfield 1611, 5016 Córdoba, Argentina
- CONICET-Universidad Nacional de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), 5016 Córdoba, Argentina
| | - Carolina Rodriguez
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Fı́sicas y Naturales. ICTA and Departamento de Quı́mica, Cátedra de Quı́mica Biológica, Avenue Vélez Sársfield 1611, 5016 Córdoba, Argentina
- CONICET-Universidad Nacional de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), 5016 Córdoba, Argentina
| | - María A Perillo
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Fı́sicas y Naturales. ICTA and Departamento de Quı́mica, Cátedra de Quı́mica Biológica, Avenue Vélez Sársfield 1611, 5016 Córdoba, Argentina
- CONICET-Universidad Nacional de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), 5016 Córdoba, Argentina
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Guluarte C, Reyes-Becerril M, Gonzalez-Silvera D, Cuesta A, Angulo C, Esteban MÁ. Probiotic properties and fatty acid composition of the yeast Kluyveromyces lactis M3. In vivo immunomodulatory activities in gilthead seabream (Sparus aurata). Fish Shellfish Immunol 2019; 94:389-397. [PMID: 31520749 DOI: 10.1016/j.fsi.2019.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/30/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
The aim of this study was to analyze the probiotic potential, fatty acid composition and immunostimulant activities of Kluyveromyces lactis M3 isolated from a hypersaline sediment. For this purpose, K. lactis M3 resistance to different pH, salinities and bile, as well as its antioxidant capability were assayed. Furthermore, total fatty acid composition of the yeast was determined where the dominant fatty acids were palmitic, palmitoleic, oleic and linoleic acids. K. lactis M3 showed no cytotoxic effects on peripheral blood leukocytes. During an in vivo experiment in gilthead seabream (Sparus aurata), dietary K. lactis M3 supplemented at 0.55 or 1.1% of the basal diet enhanced bactericidal activity against Vibrio parahaemolyticus N16, V. harveyi Lg 16/00, and V. anguillarum CECT 43442 compared to fish fed commercial diet (control group). Finally, nitric oxide production, peroxidase activity and skin mucus lectin union levels strongly increased in fish fed K. lactis M3 with respect to the control group. The results suggested that the yeast K. lactis M3 had exhibited high antioxidant capability, and its dietary administration at 0.55 or 1% basal diet had immunostimulant activity for gilthead seabream. For all these reasons, it should be considered an appropriate probiotic candidate for the aquaculture fish industry.
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Affiliation(s)
- Crystal Guluarte
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas Del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, B.C.S, 23096, Mexico
| | - Martha Reyes-Becerril
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas Del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, B.C.S, 23096, Mexico
| | - Daniel Gonzalez-Silvera
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Universidad de Murcia, 30100, Murcia, Spain
| | - Alberto Cuesta
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Universidad de Murcia, 30100, Murcia, Spain
| | - Carlos Angulo
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas Del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, B.C.S, 23096, Mexico
| | - María Ángeles Esteban
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Universidad de Murcia, 30100, Murcia, Spain.
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Yun CR, Kong JN, Chung JH, Kim MC, Kong KH. Improved Secretory Production of the Sweet-Tasting Protein, Brazzein, in Kluyveromyces lactis. J Agric Food Chem 2016; 64:6312-6316. [PMID: 27465609 DOI: 10.1021/acs.jafc.6b02446] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Brazzein is an intensely sweet protein with high stability over a wide range of pH values and temperatures, due to its four disulfide bridges. Recombinant brazzein production through secretory expression in Kluyveromyces lactis is reported, but is inefficient due to incorrect disulfide formation, which is crucial for achieving the final protein structure and stability. Protein disulfide bond formation requires protein disulfide isomerase (PDI) and Ero1p. Here, we overexpressed KlPDI in K. lactis or treated the cells with dithiothreitol to overexpress KlERO1 and improve brazzein secretion. KlPDI and KlERO1 overexpression independently increased brazzein secretion in K. lactis by 1.7-2.2- and 1.3-1.6-fold, respectively. Simultaneous overexpression of KlPDI and KlERO1 accelerated des-pE1M-brazzein secretion by approximately 2.6-fold compared to the previous system. Moreover, intracellular misfolded/unfolded recombinant des-pE1M-brazzein was significantly decreased. In conclusion, increased KlPDI and KlERO1 expression favors brazzein secretion, suggesting that correct protein folding may be crucial to brazzein secretion in K. lactis.
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Affiliation(s)
- Cho-Rong Yun
- Laboratory of Biomolecular Chemistry, Department of Chemistry, College of Natural Sciences, Chung-Ang University , 221 Huksuk-Dong, Dongjak-Ku, Seoul 156-756, Korea
| | - Ji-Na Kong
- Department of Neuroscience and Regenerative Medicine, Medical College of George, Augusta University , Augusta, Georgia 30912, United States
| | - Ju-Hee Chung
- Laboratory of Biomolecular Chemistry, Department of Chemistry, College of Natural Sciences, Chung-Ang University , 221 Huksuk-Dong, Dongjak-Ku, Seoul 156-756, Korea
| | - Myung-Chul Kim
- Laboratory of Biomolecular Chemistry, Department of Chemistry, College of Natural Sciences, Chung-Ang University , 221 Huksuk-Dong, Dongjak-Ku, Seoul 156-756, Korea
| | - Kwang-Hoon Kong
- Laboratory of Biomolecular Chemistry, Department of Chemistry, College of Natural Sciences, Chung-Ang University , 221 Huksuk-Dong, Dongjak-Ku, Seoul 156-756, Korea
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Vorob'eva LI, Khodzhaev EY, Rogozhin EA, Cherdyntseva TA, Netrusov AI. Characterization of Extracellular Yeast Peptide Factors and Their Stress-Protective Effect on Probiotic Lactic Acid Bacteria. Mikrobiologiia 2016; 85:393-402. [PMID: 28853771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Protective effect of the extracellular peptide fraction (reactivating factors, RF) produced by yeasts of various taxonomic groups (Saccharomyces cerevisiae, Kluyveromyces lactis, Candida utilis, and Yarrowia li- polytica) on probiotic lactic acid bacteria (LAB) Lactobacillus casei, L. acidophilus,'and L. reuteri under bile salt (BS)-induced stress was shown. RF of all yeasts were shown to be of peptide nature; the active component of the S. cerevisiae RF was identified as a combination of low-molecular polypeptides with molecular masses of 0.6 to 1.5 kDa. The protective and reactivating effects of the yeast factors were not species-specific and were similar to those of the Luteococcusjaponicus subsp. casei R. In BS-treated cells of the tester bacteria, a pro- tective effect was observed after 10-min preincubation of the LAB cell suspension with yeast RE: the number of surviving cells (CFU) was 2 to 4.5 times higher than in the control. The reactivating effect was observed when RF was added to LAB cell suspensions not later than 15 min after stress treatment. It was less pro- nounced than the protector effect, with the CFU number I to 3 times that of the control. Both the protector and the reactivating effects were most pronounced in the S. cerevisiae and decreased in the row: C. utilis > K. lactis > Y lipolytica. The efficiency of protective action of yeast RF was found to depend on the properties of recepient LAB cells, with the L. casei strain being most sensitive to BS treatment. In both variants, the highest protective effect of RF (increase in the CFU number) was observed for L. acidophilus, while the least pronounced one, for L. casei. The reasons for application of the LAB strains combining high stress resistance and high response to stress-protecting metabolites, including RF factors, as probiotics, is discussed.
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Kholiavka MG, Kovaleva TA, Grechkina MV, Ostankova IV, Artiukhov VG. [Inulinases from various producers: the features of their permolecular organization]. ACTA ACUST UNITED AC 2014; 50:17-24. [PMID: 25272747 DOI: 10.7868/s055510991401005x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The structural organization of inulinases from yeasts, fungi, and plants are researched. For studying their sizes, molecular weight, and permolecular organization, an approach consisting of a combination of atomic force microscopy with methods of dynamic light scattering, gel chromatography, and electrophoresis was used. It is shown that inulinases from Kluyveromyces marxianus and Aspergillus niger form geterodimers and inulinases from tubers of Helianthus tuberosus are present as both dimers and monomers. The role of various forms in the functional activity of inulinase molecules is discussed.
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Yoshida Y, Naito E, Ohishi K, Okumura T, Ito M, Sato T, Sawada H. Effect ofKluyveromyces marxianusYIT 8292 Crude Cell Wall Fraction on Serum Lipids in Normocholesterolemic and Mildly Hypercholesterolemic Subjects. Biosci Biotechnol Biochem 2014; 71:900-5. [PMID: 17420604 DOI: 10.1271/bbb.60539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hypocholesterolemic effects of Kluyveromyces marxianus YIT 8292 crude cell wall (KM-CW) were examined. In pilot studies, KM-CW tablets were administered to mildly hypercholesterolemic subjects at doses of 8.0, 4.0, 2.0, or 1.0 g/d for 4 weeks. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) decreased at doses above 2.0 and 4.0 g/d, respectively. Further, we examined the effect of intake of yogurt containing 3.0 or 4.0 g of KM-CW/d for 8 weeks in normal and hypercholesterolemic subjects in a double-blind placebo-controlled study. The intake of either of the KM-CW-containing yogurts was associated with significantly improved TC and LDL-C in hypercholesterolemic subjects, but had no effect on these levels in normal subjects. TC was significantly lower at week 8 in the hypercholesterolemic subjects who ingested yogurt containing 3.0 or 4.0 g of KM-CW than in those who consumed placebo yogurt. Intake of KM-CW might contribute to the prevention of hypercholesterolemia.
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Affiliation(s)
- Yasuto Yoshida
- Yakult Central Institute for Microbiological Research, Tokyo, Japan.
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Artiukhov VG, Kholiavka MG, Kovaleva TA. [Structural and functional properties of inulinases. Ways to regulate their activity]. Biofizika 2013; 58:635-644. [PMID: 24455883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The presented review is devoted to the analysis of structural and functional properties of inulinases from various producers. A special attention is given to the questions of molecular and permolecular organization of enzymes, description of their functional features depending upon their structural conditions and in various microenvironment. Perspectives of the development of biotechnological processes with the use of free and immobilized inulinases are discussed from a biophysical viewpoint.
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Abstract
The RNA-induced silencing complex, comprising Argonaute and guide RNA, mediates RNA interference. Here we report the 3.2 Å crystal structure of Kluyveromyces polysporus Argonaute (KpAGO) fortuitously complexed with guide RNA originating from small-RNA duplexes autonomously loaded by recombinant KpAGO. Despite their diverse sequences, guide-RNA nucleotides 1-8 are positioned similarly, with sequence-independent contacts to bases, phosphates and 2'-hydroxyl groups pre-organizing the backbone of nucleotides 2-8 in a near-A-form conformation. Compared with prokaryotic Argonautes, KpAGO has numerous surface-exposed insertion segments, with a cluster of conserved insertions repositioning the N domain to enable full propagation of guide-target pairing. Compared with Argonautes in inactive conformations, KpAGO has a hydrogen-bond network that stabilizes an expanded and repositioned loop, which inserts an invariant glutamate into the catalytic pocket. Mutation analyses and analogies to ribonuclease H indicate that insertion of this glutamate finger completes a universally conserved catalytic tetrad, thereby activating Argonaute for RNA cleavage.
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Affiliation(s)
- Kotaro Nakanishi
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - David E. Weinberg
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David P. Bartel
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Dinshaw J. Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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Yamaguchi M, Noda NN, Yamamoto H, Shima T, Kumeta H, Kobashigawa Y, Akada R, Ohsumi Y, Inagaki F. Structural insights into Atg10-mediated formation of the autophagy-essential Atg12-Atg5 conjugate. Structure 2012; 20:1244-54. [PMID: 22682742 DOI: 10.1016/j.str.2012.04.018] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/24/2012] [Accepted: 04/25/2012] [Indexed: 01/07/2023]
Abstract
The Atg12-Atg5 conjugate, which is formed by an ubiquitin-like conjugation system, is essential to autophagosome formation, a central event in autophagy. Despite its importance, the molecular mechanism of the Atg12-Atg5 conjugate formation has not been elucidated. Here, we report the solution and crystal structures of Atg10 and Atg5 homologs from Kluyveromyces marxianus (Km), a thermotolerant yeast. KmAtg10 comprises an E2-core fold with characteristic accessories, including two β strands, whereas KmAtg5 has two ubiquitin-like domains and a helical domain. The nuclear magnetic resonance experiments, mutational analyses, and crosslinking experiments showed that KmAtg10 directly recognizes KmAtg5, especially its C-terminal ubiquitin-like domain, by its characteristic two β strands. Kinetic analysis suggests that Tyr56 and Asn114 of KmAtg10 may place the side chain of KmAtg5 Lys145 into the optimal orientation for its conjugation reaction with Atg12. These structural features enable Atg10 to mediate the formation of the Atg12-Atg5 conjugate without a specific E3 enzyme.
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Affiliation(s)
- Masaya Yamaguchi
- Department of Structural Biology, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
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Abstract
Microbial cells (Kluyveromyces fragilis and Chlorella vulgaris) efficiently interacted with maghemite nanoparticles stabilized as low-pH ionic magnetic fluid, leading to the formation of magnetically labeled cells. This simple procedure allows to use the prepared materials as new cheap and easy to get magnetic affinity adsorbents to the removal of water-soluble dyes from polluted water sources using magnetic separation techniques. Magnetically modified cells were investigated by means of electron spin resonance spectroscopy and conventional magnetic methods over the temperature range 4-300 K. The magnetic behavior of these materials was dominated by the superparamagnetic relaxation of isolated single domain maghemite particles although a little amount of agglomerates was also present on the cell surface. However, these agglomerates were sufficiently small to show at static conditions the superparamagnetic behavior at room temperature. Therefore, the ferrofluid-modified microbial cells represent new interesting magnetic affinity adsorbents which could be applied for large-scale magnetic separation processes.
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Yoshida Y, Naito E, Mizukoshi H, Watanabe Y, Kimura K, Yokoi W, Sato T, Okumura T, Ito M, Sawada H. Side-chain structure of cell surface polysaccharide, mannan, affects hypocholesterolemic activity of yeast. J Agric Food Chem 2009; 57:8003-8009. [PMID: 19670864 DOI: 10.1021/jf900347q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We previously reported that Kluyveromyces marxianus YIT 8292 exhibited more potent hypocholesterolemic activity than other yeasts containing Saccharomyces cerevisiae . To clarify the reason for the higher hypocholesterolemic activity, we examined the side-chain structure of cell surface polysaccharide, mannan, of K. marxianus YIT 8292. The result shows that K. marxianus YIT 8292 had shorter alpha-(1,2)-linked oligomannosyl side chains and lower phosphate content in mannan than S. cerevisiae. The association between its structural features and hypocholesterolemic activity was investigated by comparing the hypocholesterolemic activities of S. cerevisiae mannan mutants in rats fed a high-cholesterol diet. S. cerevisiae mnn5 mutant with deficiencies in the phosphorylation and elongation of mannan side chains showed higher hypocholesterolemic activity than the wild-type strain. These results show that the side-chain length and phosphate contents of mannan affect hypocholesterolemic activity.
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Affiliation(s)
- Yasuto Yoshida
- Yakult Central Institute for Microbiological Research, Kunitachi-shi, Tokyo 186-8650, Japan.
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Núñez L, González-Siso MI, Becerra M, Cerdán ME. Functional motifs outside the kinase domain of yeast Srb10p. Their role in transcriptional regulation and protein-interactions with Tup1p and Srb11p. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2007; 1774:1227-35. [PMID: 17689156 DOI: 10.1016/j.bbapap.2007.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 06/21/2007] [Accepted: 06/26/2007] [Indexed: 11/16/2022]
Abstract
Several derivatives of the native Srb10 proteins from Saccharomyces cerevisiae and Kluyveromyces lactis, with removed selected motifs, have been constructed in order to test their role in Srb10p function. It has been demonstrated that the ATP binding site is necessary for repression of FLO11, CYC7 and SPI1. Yeast Srb10p specific motifs CM-I and CM-II, outside the kinase domain, are also necessary to complement two mutant phenotypes in S. cerevisiae Deltasrb10 strains, the failure to growth in galactose at 37 degrees C and flocculation. They are also required to keep transcriptional repression of FLO11 in non-flocculants, and for aerobic repression of CYC7 and SPI1. Two-hybrid analyses revealed that, in Srb10p derivatives, the absence of these motifs decreases the interaction of Srb10p with its cyclin partner Srb11p and with the component Tup1p of the general co-repressor complex Tup1p-Ssn6p.
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Affiliation(s)
- Laura Núñez
- Departamento de Biología Celular y Molecular. Facultad de Ciencias, Universidad de A Coruña, 15071, Spain
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16
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Moreau M, Neveu M, Stéphan S, Noblesse E, Nizard C, Sadick NS, Schnebert S, Bonté F, Dumas M, Andre P, Perrier E. Enhancing cell longevity for cosmetic application: a complementary approach. J Drugs Dermatol 2007; 6:s14-9. [PMID: 17691205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
BACKGROUND AND OBJECTIVES Cell longevity is linked to sirtuins (silent information regulators), which belong to a family of enzymes implicated in gene silencing, apoptosis, fatty acid metabolism, and regulation of cellular life spans of organisms. Sirtuins are associated with genes that coordinate and optimize the functions of cells as cells struggle to survive in a stressful environment, as it is the case for skin cells. This study focuses on 1) yeast Kluyveromyces biopetides in stimulating the expression of sirtuin in human cutaneous cells and 2) the benefit for the skin of an active skin care product containing yeast Kluyveromyces biopetides. METHODS Silent mating type information regulation 2 homolog 1 (SIRT1) was investigated by immunostaining, Westem blotting, and cytometry on normal human skin cells in culture and on healthy skin samples ex vivo. SIRT7 are mammalian versions of the yeast SIR2 gene. Cellular integrity and aging was followed by comet assays measuring DNA fragmentation and beta galactosidase activity (a marker of senescence). The test product was yeast Kluyveromyces biopeptides. Thirty-three female subjects aged 37 to 64 years (mean 51.6 years) enrolled in the study. Subjects applied a formulation enriched in 1% of the yeast biopeptides SIRT1 activator once daily to the face and neck for 4 weeks. Dermatologists used a graded scale (1-9) to score fine lines and wrinkles, hydration, pigment color intensity, complexion radiance, skin density, firmness, complexion homogeneity, and texture of the skin before and after the first application and again after 4 weeks of use. A Pixel Skin method, based on an analysis of the gray-level variance and surface of imperfections (age-related parameters) from numerical pictures of the faces, was used to objectively measure the skin care efficacy. RESULTS The yeast Kluyveromyces biopeptides 1) significantly increased SIRT1 expression in normal human dermal skin fibroblasts in vitro (+172%) and in epidermal cells of healthy human skin ex vivo and 2) decreased cell senescence and DNA fragmentation induced by ultraviolet-B (UVB) stress. At the end of the study, facial improvements could be seen on fine lines and wrinkles, hydration, pigmented spot color intensity, complexion radiance, firmness, complexion homogeneity, and texture. Improvement in hydration was significant immediately after the first application. Skin-pixel measurement and analysis show a significant reduction of the gray variance linked to pixel heterogeneity (-4.2%) and a significant reduction of the surface of skin imperfections (-30.4%). All the indicators from clinical evaluation to the objective measurements of the skin show a significant improvement of the aged skin. CONCLUSION These results demonstrate the efficacy of the yeast Kluyveromyces biopeptides in activating SIRT 1 of human skin cells, improving their DNA resistance and senescence, and of a formulation enriched in this ingredient in treating multiple skin aging signs.
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Affiliation(s)
- Marielle Moreau
- LVMH Recherche - Parfums Christian Dior, St. Jean de Braye, France
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17
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Fukuhara H. Nineteenth 'Biology of Kluyveromyces' workshop, Parma, Italy, 16-17 September 2006. FEMS Yeast Res 2006; 6:1288-9. [PMID: 17156026 DOI: 10.1111/j.1567-1364.2006.00181.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Hiroshi Fukuhara
- Institut Curie, Section de Recherche, Centre Universitaire Paris, France.
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18
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Kutter S, Wille G, Relle S, Weiss MS, Hübner G, König S. The crystal structure of pyruvate decarboxylase from Kluyveromyces lactis. Implications for the substrate activation mechanism of this enzyme. FEBS J 2006; 273:4199-209. [PMID: 16939618 DOI: 10.1111/j.1742-4658.2006.05415.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The crystal structure of pyruvate decarboxylase from Kluyveromyces lactis has been determined to 2.26 A resolution. Like other yeast enzymes, Kluyveromyces lactis pyruvate decarboxylase is subject to allosteric substrate activation. Binding of substrate at a regulatory site induces catalytic activity. This process is accompanied by conformational changes and subunit rearrangements. In the nonactivated form of the corresponding enzyme from Saccharomyces cerevisiae, all active sites are solvent accessible due to the high flexibility of loop regions 106-113 and 292-301. The binding of the activator pyruvamide arrests these loops. Consequently, two of four active sites become closed. In Kluyveromyces lactis pyruvate decarboxylase, this half-side closed tetramer is present even without any activator. However, one of the loops (residues 105-113), which are flexible in nonactivated Saccharomyces cerevisiae pyruvate decarboxylase, remains flexible. Even though the tetramer assemblies of both enzyme species are different in the absence of activating agents, their substrate activation kinetics are similar. This implies an equilibrium between the open and the half-side closed state of yeast pyruvate decarboxylase tetramers. The completely open enzyme state is favoured for Saccharomyces cerevisiae pyruvate decarboxylase, whereas the half-side closed form is predominant for Kluyveromyces lactis pyruvate decarboxylase. Consequently, the structuring of the flexible loop region 105-113 seems to be the crucial step during the substrate activation process of Kluyveromyces lactis pyruvate decarboxylase.
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Affiliation(s)
- Steffen Kutter
- Institute for Biochemistry, Department of Biochemistry & Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
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19
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Abstract
Kluyveromyces lactis killer strains secrete a heterotrimeric toxin (zymocin), which causes an irreversible growth arrest of sensitive yeast cells. Despite many efforts, the target(s) of the cytotoxic gamma-subunit of zymocin has remained elusive. Here we show that three tRNA species tRNA(Glu)(mcm(5)s(2)UUC), tRNA(Lys)(mcm(5)s(2)UUU), and tRNA(Gln)(mcm(5)s(2)UUG) are the targets of gamma-toxin. The toxin inhibits growth by cleaving these tRNAs at the 3' side of the modified wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U). Transfer RNA lacking a part of or the entire mcm(5) group is inefficiently cleaved by gamma-toxin, explaining the gamma-toxin resistance of the modification-deficient trm9, elp1-elp6, and kti11-kti13 mutants. The K. lactis gamma-toxin is the first eukaryotic toxin shown to target tRNA.
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Affiliation(s)
- Jian Lu
- Department of Molecular Biology, Umeå University, Sweden
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20
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Schultz N, Chang L, Hauck A, Reuss M, Syldatk C. Microbial production of single-cell protein from deproteinized whey concentrates. Appl Microbiol Biotechnol 2005; 69:515-20. [PMID: 16133331 DOI: 10.1007/s00253-005-0012-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Revised: 04/18/2005] [Accepted: 04/23/2005] [Indexed: 10/25/2022]
Abstract
Deproteinized sweet and sour cheese whey concentrates were investigated for their suitability as substrates for the production of single-cell protein with Kluyveromyces marxianus CBS 6556 up to a 100-l scale. An important factor for gaining high cell concentrations was the use of the Crabtree-negative strain K. marxianus CBS 6556. Supplements such as trace elements, ammonium and calcium were required for the complete conversion of sweet whey concentrates into biomass, whereas sour whey concentrates had to be supplemented with ammonium, trace elements and vitamins. After improvement, biomass dry concentrations of up to 50 g l-1 could be reached with Yx/s values of 0.52 for sweet whey and of up to 65 g l-1 with Yx/s values of 0.48 for sour whey concentrates. The chemical oxygen demand of the whey concentrates were reduced by 80%. The cells were used for the analysis of amino acid and ash composition, showing a distinct increase of eight out of ten essential amino acids compared to sweet and sour whey protein and exceeding the World Health Organisation guidelines for valine, leucine, isoleucine, threonine, phenylalanine and tyrosine.
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Affiliation(s)
- Nadja Schultz
- Universität Stuttgart, Institut für Bioverfahrenstechnik, Allmandring 31, 70569, Stuttgart, Germany.
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21
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Wiedemuth C, Breunig KD. Role of Snf1p in regulation of intracellular sorting of the lactose and galactose transporter Lac12p in Kluyveromyces lactis. Eukaryot Cell 2005; 4:716-21. [PMID: 15821131 PMCID: PMC1087813 DOI: 10.1128/ec.4.4.716-721.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Accepted: 02/04/2005] [Indexed: 11/20/2022]
Abstract
The protein kinase Snf1/AMPK plays a central role in carbon and energy homeostasis in yeasts and higher eukaryotes. To work out which aspects of the Snf1-controlled regulatory network are conserved in evolution, the Snf1 requirement in galactose metabolism was analyzed in the yeast Kluyveromyces lactis. Whereas galactose induction was only delayed, K. lactis snf1 mutants failed to accumulate the lactose/galactose H+ symporter Lac12p in the plasma membran,e as indicated by Lac12-green fluorescent protein fusions. In contrast to wild-type cells, the fusion protein was mostly intracellular in the mutant. Growth on galactose and galactose uptake could be restored by the KHT3 gene, which encodes a new transporter of the HXT subfamily of major facilitators These findings indicate a new role of Snf1p in regulation of sugar transport in K. lactis.
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Affiliation(s)
- Christian Wiedemuth
- Institut für Genetik, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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22
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Spark M, Paschertz H, Kamphues J. Yeast (different sources and levels) as protein source in diets of reared piglets: effects on protein digestibility and N-metabolism. J Anim Physiol Anim Nutr (Berl) 2005; 89:184-8. [PMID: 15787992 DOI: 10.1111/j.1439-0396.2005.00552.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aim of this study was to examine the feeding value of different yeasts as a substitute for soya bean meal, the main protein source in diets of weaned piglets. Tested two yeasts were already available on the market, Saccharomyces cerevisiae and Kluyveromyces lactis (beer and milk yeast), which replaced 40% of the soya bean meal in the diets. Furthermore, a yeast (Kluyveromyces fragilis) grown on whey, a side-product of cheese production, was used in increasing concentrations in the diets, so that increasing amounts of the soya bean meal (20%, 40% and 60%) could be replaced. As proved in these experiments, a replacement of 60% of the soya protein with whey yeast protein had positive effects on the performances (daily weight gain) and on the N-metabolism and did not have negative effects on the health or the faeces consistency. The whey yeast stands out because of its high protein quality (N-digestibility and N-retention). Furthermore, the replacement of soya bean meal with highly digestible yeasts is welcomed under the aspect of animal health, because of the reduction of anti-nutritive soya components (stachyose, glycinin) in diets of weaned piglets. The controlled production conditions of the yeasts result in a high feed safety; in addition, the yeast as an end-of-pipe-product is a resource conserving and valuable feed. A main stimulus for the use of yeasts, however, in a food production controlled by economic standpoints, is their price and the costs of other competing feeds.
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Affiliation(s)
- M Spark
- Institute of Animal Nutrition, University of Veterinary Medicine Hannover, D-30173 Hannover, Germany
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23
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de Alteriis E, Silvestro G, Poletto M, Romano V, Capitanio D, Compagno C, Parascandola P. Kluyveromyces lactis cells entrapped in Ca-alginate beads for the continuous production of a heterologous glucoamylase. J Biotechnol 2004; 109:83-92. [PMID: 15063616 DOI: 10.1016/j.jbiotec.2003.10.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2002] [Revised: 10/06/2003] [Accepted: 10/14/2003] [Indexed: 11/26/2022]
Abstract
Viable cells of Kluyveromyces lactis, transformed with the glucoamylase gene from Arxula adeninivorans, were entrapped in beads of Ca-alginate and employed on a lab scale in a continuous stirred and a fluidised bed reactor (FBR), both fed with a rich medium (YEP) containing lactose as carbon source. Experiments with freely suspended cells in batch and chemostat had demonstrated that glucoamylase production was favoured in the presence of lactose and YEP medium. Employing controlled-sized beads having a 2.13 mm diameter, specific glucoamylase productivity was higher in the stirred reactor (CSTR) than in the FBR; in the latter a higher volumetric productivity was achieved, due to the lower void degree. The performance of the immobilised cell systems, in terms of specific glucoamylase productivity, was strongly affected by mass transfer limitations occurring throughout the gel due to the high molecular weight of the product. In the perspective to improve and scale-up the immobilised cell system proposed, a mathematical model, which takes into account substrate transfer limitations throughout the gel, has been developed. The effective lactose diffusivity was related to the bead reactive efficiency by means of the Thiele modulus. The regression of the model parameters on the experimental data of substrate consumption obtained both in the CSTR and in the FBR allowed to estimate lactose diffusivity and the kinetic parameters of the immobilised yeast.
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Affiliation(s)
- Elisabetta de Alteriis
- Sez. Igiene e Microbiologia, Dip.to di Fisiologia Generale ed Ambientale, Università degli Studi di Napoli Federico II, Via Mezzocannone 16, 80134 Naples, Italy
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24
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Comitini F, Pietro ND, Zacchi L, Mannazzu I, Ciani M. Kluyveromyces phaffii killer toxin active against wine spoilage yeasts: purification and characterization. Microbiology (Reading) 2004; 150:2535-2541. [PMID: 15289550 DOI: 10.1099/mic.0.27145-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The killer toxin secreted by Kluyveromyces phaffii (KpKt) is active against spoilage yeast under winemaking conditions and thus has potential applications in the biocontrol of undesired micro-organisms in the wine industry. Biochemical characterization and N-terminal sequencing of the purified toxin show that KpKt is a glycosylated protein with a molecular mass of 33 kDa. Moreover, it shows 93% and 80% identity to a beta-1,3-glucanase of Saccharomyces cerevisiae and a beta-1,3-glucan transferase of Candida albicans, respectively, and it is active on laminarin and glucan, thus showing a beta-glucanase activity. Competitive inhibition of killer activity by cell-wall polysaccharides suggests that glucan (beta-1,3 and beta-1,6 branched glucans) represents the first receptor site of the toxin on the envelope of the sensitive target. Flow cytometry analysis of the sensitive target after treatment with KpKt and K1 toxin of S. cerevisiae, known to cause loss of cell viability via formation of pores in the cell membrane, suggests a different mode of action for KpKt.
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Affiliation(s)
- Francesca Comitini
- Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Natalia Di Pietro
- Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Laura Zacchi
- Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Ilaria Mannazzu
- Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Maurizio Ciani
- Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
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25
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Abstract
Certain strains of Pichia acaciae and Wingea robertsiae (synonym Debaryomyces robertsiae) harbour extranuclear genetic elements that confer a killer phenotype to their host. Such killer plasmids (pPac1-2 of P. acaciae and pWR1A of W. robertsiae) were sequenced and compared with the zymocin encoding pGKL1 of Kluyveromyces lactis. Both new elements were found to be closely related to each other, but they are only partly similar to pGKL1. As for the latter, they encode functions mediating binding of the toxin to the target cell's chitin and a hydrophobic region potentially involved in uptake of a toxin subunit by target cells. Consistently, mutations affecting the target cell's major chitin synthase (Chs3) protect it from toxin action. Heterologous intracellular expression of respective open reading frames identified cell cycle-arresting toxin subunits deviating structurally from the likewise imported gamma-subunit of the K. lactis zymocin. Accordingly, toxicity of both P. acaciae and Wingea toxins was shown to be independent of RNA polymerase II Elongator, which is indispensable for zymocin action. Thus, P. acaciae and Wingea toxins differ in their mode of action from the G1-arresting zymocin. Fluorescence-activated cell sorting analysis and determination of budding indices have proved that such novel toxins mediate cell cycle arrest post-G1 during the S phase. Concomitantly, the DNA damage checkpoint kinase Rad53 is phosphorylated. As a mutant carrying the checkpoint-deficient allele rad53-11 displays toxin hypersensitivity, damage checkpoint activation apparently contributes to coping with toxin stress, rather than being functionally implemented in toxin action.
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Affiliation(s)
- Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstr. 3, D-48149 Münster, Germany
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26
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Abstract
Kluyveromyces marxianus was grown in submerged culture in a complex medium with several potential inducers of lipolytic activity (triacylglycerols, fatty acids). The highest extracellular lipolytic enzyme production (about 80 U ml(-1) in 3 d) was obtained when the medium was supplemented with 2 g urea l(-1) plus 5 g tributyrin l(-1). Addition of surfactants (1 g l(-1)) did not improve production. The lipase had a high thermal stability in aqueous solution (73% residual activity after 9 d at 50 degrees C, 16 min half-life time at 100 degrees C). It was also stable at acidic pH and showed good tolerance to organic solvents (70% residual activity after 2 d in n-hexane of cyclohexane).
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Affiliation(s)
- F J Deive
- Department of Chemical Engineering, University of Vigo, 36200 Vigo, Spain
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27
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Menezes RA, Amuel C, Engels R, Gengenbacher U, Labahn J, Hollenberg CP. Sites for interaction between Gal80p and Gal1p in Kluyveromyces lactis: structural model of galactokinase based on homology to the GHMP protein family. J Mol Biol 2003; 333:479-92. [PMID: 14556739 DOI: 10.1016/j.jmb.2003.08.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The induction of transcription of the galactose genes in yeast involves the galactose-dependent binding of ScGal3p (in Saccharomyces cerevisiae) or KlGal1p (in Kluyveromyces lactis) to Gal80p. This binding abrogates Gal80's inhibitory effect on the activation domain of Gal4p, which can then activate transcription. Here, we describe the isolation and characterization of new interaction mutants of K.lactis GAL1 and GAL80 using a two-hybrid screen. We present the first structural model for Gal1p to be based on the published crystal structures of other proteins belonging to the GHMP (galactokinase, homoserine kinase, mevalonate kinase and phosphomevalonate kinase) kinase family and our own X-ray diffraction data of Gal1p crystals at 3A resolution. The locations of the various mutations in the modelled Gal1p structure identify domains involved in the interaction with Gal80p and provide a structural explanation for the phenotype of constitutive GAL1 mutations.
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Affiliation(s)
- R A Menezes
- Institut für Mikrobiologie and Biologisch-Medizinisches Forschungszentrum, Heinrich-Heine-Universität, Universitätsstr. 1, D-40225, Düsseldorf, Germany
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28
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Bahmed K, Quilès F, Bonaly R, Coulon J. Fluorescence and Infrared Spectrometric Study of Cell Walls from Candida, Kluyveromyces, Rhodotorula and Schizosaccharomyces Yeasts in Relation with Their Chemical Composition. Biomacromolecules 2003; 4:1763-72. [PMID: 14606907 DOI: 10.1021/bm034175n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Composition, level, and arrangement of the structural polysaccharides determine biophysical properties of fungal cell walls. A small amount of a beta(1-->4) linear homopolymer of GlcNAc in the cell wall forms chitin. To study the components of the cell walls and to estimate the quantity of chitin for different strains, two spectroscopic methods were applied. Because chemical and enzymatic methods are destructive, long, and complex, fluorescence and infrared (IR) spectroscopies were applied on cell walls and on chitin enriched fractions. The results were compared to chemical assays. IR spectra allow identifying the structural types of polysaccharides in yeast walls. Fluorescence spectroscopy was not appropriated for a full and accurate quantitative determination of the polymers but revealed level variations similar to results obtained by chemical analytical methods. The infrared spectra, using a chemometric approach (PLS1), allowed a fairly good estimation of chitin in enriched fractions with respect to the chemical assays.
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Affiliation(s)
- Karim Bahmed
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), U.M.R. 7564 CNRS-Université Henri Poincaré, Nancy 1, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy, France
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29
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Diezemann A, Boles E. Functional characterization of the Frt1 sugar transporter and of fructose uptake in Kluyveromyces lactis. Curr Genet 2003; 43:281-8. [PMID: 12677461 DOI: 10.1007/s00294-003-0392-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Revised: 02/25/2003] [Accepted: 02/25/2003] [Indexed: 11/26/2022]
Abstract
Most yeast hexose transporters studied so far at the molecular level mediate facilitated diffusion of glucose and fructose. Here, we report that a novel Kluyveromyces lactis gene, FRT1, encodes a proton-coupled fructose-uptake transporter. Frt1, when expressed in a Saccharomyces cerevisiae hxt null mutant strain that is unable to take up monosaccharides, restored growth on fructose. Determination of substrate specificities and kinetic parameters revealed Frt1 as a fructose transporter with a K(m) of 0.16+/-0.02 mM. Uptake of fructose was accompanied by an initial alkalization of the medium, indicating a proton-coupled uptake mechanism. Deletion of the FRT1 gene in a K. lactis strain already deleted for its RAG1 and HGT1 hexose transporter genes completely prevented uptake of and growth with fructose but not with glucose. Kinetic parameters of Frt1 in K. lactis, as assessed in a rag1 hgt1 mutant strain, were comparable with those obtained after heterologous expression in S. cerevisiae. Transcription of the FRT1 gene, which was undetectable when cells were grown in ethanol, was induced by various sugars. Our results indicate that, unlike S. cerevisiae, K. lactis exhibits proton symport systems for the uptake of hexoses, in addition to their facilitated diffusion.
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Affiliation(s)
- Anja Diezemann
- Institut für Mikrobiologie, Heinrich-Heine-Universität, Universitätsstrasse 1, Geb. 26.12.01, 40225, Düsseldorf, Germany
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Miyakawa I, Sato H, Maruyama Y, Nakaoka T. Isolation of the mitochondrial nucleoids from yeast Kluyveromyces lactis and analyses of the nucleoid proteins. J GEN APPL MICROBIOL 2003; 49:85-93. [PMID: 12833211 DOI: 10.2323/jgam.49.85] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Mitochondrial (mt) nucleoids were isolated from yeast Kluyveromyces lactis with morphological intactness. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed more than 20 proteins that are associated with the mt-nucleoids. However, the protein profile of the mt-nucleoids of K. lactis was significantly different from that of the mt-nucleoid proteins from Saccharomyces cerevisiae. SDS-DNA PAGE, which detected an Abf2p, a major mitochondrial DNA-binding protein, among the mt-nucleoid proteins of S. cerevisiae on a gel, detected only a 17-kDa protein in the K. lactis mt-nucleoid proteins. The 17-kDa protein was purified as homogeneous from the mt-nucleoids by a combination of acid extraction, hydroxyapatite chromatography and DNA-cellulose chromatography. The 17-kDa protein introduced a negative supercoil into circular plasmid DNA in the presence of topoisomerase I, as does S. cerevisiae Abf2p, and it packed K. lactis mtDNA into nucleoid-like particles in vitro. These results, together with the determination of the N-terminal amino acid sequence, suggested that the 17-kDa protein is an Abf2p homologue of K. lactis and plays structural roles in compacting mtDNA in cooperation with other nucleoid proteins.
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Affiliation(s)
- Isamu Miyakawa
- Department of Physics, Informatics and Biology, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan.
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Lukondeh T, Ashbolt NJ, Rogers PL. Evaluation of Kluyveromyces marxianus as a source of yeast autolysates. J Ind Microbiol Biotechnol 2003; 30:52-6. [PMID: 12545387 DOI: 10.1007/s10295-002-0008-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2001] [Accepted: 09/30/2002] [Indexed: 10/23/2022]
Abstract
Cells of Kluyveromyces marxianus FII 510700 and Saccharomyces cerevisiae CBS 1907 were autolysed in phosphate buffer, pH 4.5, for a maximum of 10 days to compare chemical changes that occur in the carbohydrate, protein, amino acid and nucleic acid content. Approximately 2.2-3% carbohydrate, 9.5-12% protein, 0.6-1.0% DNA and 6-7% RNA were recovered in the autolysates. The main amino acids were beta-alanine, phenylalanine, cysteine, methionine, glutamic acid and isoleucine. No significant differences in the yeast autolysates of K. marxianus and S. cerevisiae were observed. Consequently, K. marxianus produced from lactose-based media has potential as a source of yeast autolysates used in the food industry.
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Affiliation(s)
- Tredwell Lukondeh
- School of Civil and Environmental Engineering, The University of New South Wales, UNSW-Sydney 2052, Australia.
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Zhao Y, Liang S, Huang K, Huang R. [Construction of a set of secreting expression vectors for Saccharomyces cerevisiea]. Wei Sheng Wu Xue Bao 2002; 42:431-5. [PMID: 12557548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The DNA fragment ecoding the Signal peptide of inulinase of Kluyveromyces smarxianu was synthesized chemically. This fragment was cloned in-frame in the expression vector pYES2 of Saccharomyces cerevisiae, resulting in a set of new secreting expression vectors pYES2 I, pYES2 II, pYES2 III. The L-Asparaginase gene (ASN) of E. coli and alpha-acetylactate decarboxylase gene (ALDC) of B. brevis which were amplified by PCR and cloned into the new vectors respectively were transformed into Saccharomyces cerevisia, and most of enzyme activities were secreted into the medium. The new secreting expression vectors still have excellent segregational stability even after growth for 100 h in the absence of selective pressure.
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Affiliation(s)
- Yingyi Zhao
- Institute of Food and Biology Engineering, South China Science and Technology University, Guangzhou 510640, China
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33
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Paul D, Mukhopadhyay R, Chatterjee BP, Guha AK. Nutritional profile of food yeast Kluyveromyces fragilis biomass grown on whey. Appl Biochem Biotechnol 2002; 97:209-18. [PMID: 11998844 DOI: 10.1385/abab:97:3:209] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2001] [Revised: 09/10/2001] [Accepted: 09/10/2001] [Indexed: 11/11/2022]
Abstract
Biomass of food yeast Kluyveromyces fragilis (MTCC 188) grown on deproteinized whey supplemented with 0.8% diammonium hydrogen phosphate and 10 ppm indole-3-acetic acid, had a crude protein content of 37%. The true protein content based on nitrogen fractionation procedure was 28.1%. Total nucleic acid content was 4.82%. This amount does not appear to be toxicologically offensive. Crude fiber, ash, and lipid content of K.fragilis dry cells were found to be 4.9%, 16%, and 7.8%, respectively. Essential fatty acids of both omega-3 and omega-6 series were found present in the fat of the yeast and represented 21.5% of the total fatty acids. All the essential amino acids were present in the proteins of K. fragilis; however, sulfur containing amino acids were found in lower amounts. Calculated protein scores indicate moderate biological value. B vitamins in the biomass were present as expected, but folic acid and pyridoxine were present in high concentration.
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Affiliation(s)
- Deepen Paul
- Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Calcutta
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34
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Belloch C, Fernández-Espinar T, Querol A, Dolores García M, Barrio E. An analysis of inter- and intraspecific genetic variabilities in the Kluyveromyces marxianus group of yeast species for the reconsideration of the K. lactis taxon. Yeast 2002; 19:257-68. [PMID: 11816033 DOI: 10.1002/yea.832] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In the present work, we analyse the sequences of the 5.8S rRNA gene and the two internal transcribed spacers 1 and 2 (5.8S-ITS region), obtained from 39 strains belonging to the species Kluyveromyces aestuarii, K. dobzhanskii, K. lactis and K. marxianus, K. nonfermentans and K. wickerhamii, to solve the phylogenetic relationships among these species and also to determine the possible genetic basis for the delimitation of the two currently accepted K. lactis varieties: lactis, including lactose-positive strains isolated from dairy products, and drosophilarum, comprising lactose-negative strains isolated from insects and plant exudates. The determination of the phylogenetic relationships within the species K. lactis, together with the examination of the electrophoretic karyotypes and phenotypic characterization of strains representatives of K. lactis var. lactis and var. drosophilarum, allowed differentiation of two groups of strains. The first, and ancestral, group comprises lactose-negative strains isolated from natural habitats in North America. The second, and derived, group includes both lactose-negative strains isolated from natural habitats in Europe and wine fermentation in South Africa, and lactose-positive strains associated with dairy products. These results suggest that the present taxon K. lactis is a complex of different species, subspecies or, at least, genetically structured populations.
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MESH Headings
- Base Sequence
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- DNA, Ribosomal Spacer/chemistry
- DNA, Ribosomal Spacer/genetics
- Electrophoresis, Gel, Pulsed-Field
- Europe
- Food Microbiology
- Genetic Variation
- Kluyveromyces/chemistry
- Kluyveromyces/classification
- Kluyveromyces/genetics
- Molecular Sequence Data
- North America
- Phylogeny
- Polymerase Chain Reaction
- Polymorphism, Genetic/genetics
- RNA, Ribosomal, 5.8S/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- South Africa
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Affiliation(s)
- Carmela Belloch
- Colección Española de Cultivos Tipo (CECT), Universitat de Valencia, Calle Dr Moliner 50, 46100 Burjassot, Valencia, Spain
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35
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Géhin G, Coulon J, Coleman A, Bonaly R. Isolation and biochemical characterization of cell wall tight protein complex involved in self-flocculation of Kluyveromyces bulgaricus. Antonie Van Leeuwenhoek 2001; 80:225-36. [PMID: 11827208 DOI: 10.1023/a:1013014709607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Flocculation of yeasts is a cell-cell aggregation phenomenon which is driven by interactions between cell wall lectins and cell wall heteropolysaccharides. In Sabouraud medium, Kluyveromyces bulgaricus was highly flocculent. Incubation of flocculent K. bulgaricus cells with EDTA or Hecameg led to extracts showing hemagglutinating and flocculating properties. Purification of the extracts by native PAGE gave two bands which allowed flocculation of deflocculated K. bulgaricus. Both bands with specific reflocculating activity were composed of five subunits, of which only three possessed weak reflocculating activity upon deflocculated yeast. The mixture of these three proteins allow the recovery of initial specific reflocculating activity of the complex. These three proteins, denoted p28, p36 and p48, presented, in their first 15 amino acids, homologies with glycolysis enzymes, i.e., 3-phosphoglycerate mutase, glyceraldehyde-3-phosphate dehydrogenase and enolase, respectively. However, no such enzymatic activity could be detected in the crude extract issued from treatment with EDTA and Hecameg of flocculent yeast cells. When yeasts had grown in glucose poor medium, flocculation was drastically affected. The EDTA and Hecameg crude extracts showed weak reflocculating activity. After PAGE, the protein complexes did not appear in the EDTA extract, but they did appear in the Hecameg crude extract. These results suggest that: (i) self-flocculation of K. bulgaricus depends on the expression of different floc-forming protein complex, (ii) these proteins are galactose specific lectins showing homologies in their primary structure with glycolysis enzymes.
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Affiliation(s)
- G Géhin
- Laboratoire de Biochimie Microbienne, LCPE, UMR 7564-CNRS-UHP, Nancy, France
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36
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Abstract
We present here three high-resolution crystal structures of complexes between the DNA-binding domain of the heat-shock transcription factor (HSF) and DNA oligomers. Although the DNA oligomers contain HSF's specific binding sequence, called a heat-shock element, the crystal structures do not contain the specific protein-DNA complex. In one crystal structure, the 10 base pair DNA oligomer is statically disordered. In the other two related structures, the 12 base pair DNA oligomers are in unique positions, but the protein-DNA contacts in these two crystals are not sequence specific. In all three structures, the DNA appears to act as a rigid, polyanion scaffold to support columns of proteins in a crystalline lattice. A robust crystal packing interface between protein monomers obscures the true DNA-binding surface, known from previous genetic and biochemical studies. By redesigning the protein to interfere with the crystal lattice contacts, we were able to obtain physiologically relevant crystals in a specific protein-DNA complex. Thus, a crystal-packing interface was able to prevent the weak, but physiological relevant interactions between a protein and DNA.
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Affiliation(s)
- O Littlefield
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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37
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Bulman AL, Hubl ST, Nelson HC. The DNA-binding domain of yeast heat shock transcription factor independently regulates both the N- and C-terminal activation domains. J Biol Chem 2001; 276:40254-62. [PMID: 11509572 DOI: 10.1074/jbc.m106301200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of heat shock proteins in response to cellular stresses is dependent on the activity of the heat shock transcription factor (HSF). In yeast, HSF is constitutively bound to DNA; however, the mitigation of negative regulation in response to stress dramatically increases transcriptional activity. Through alanine-scanning mutagenesis of the surface residues of the DNA-binding domain, we have identified a large number of mutants with increased transcriptional activity. Six of the strongest mutations were selected for detailed study. Our studies suggest that the DNA-binding domain is involved in the negative regulation of both the N-terminal and C-terminal activation domains of HSF. These mutations do not significantly affect DNA binding. Circular dichroism analysis suggests that a subset of the mutants may have altered secondary structure, whereas a different subset has decreased thermal stability. Our findings suggest that the regulation of HSF transcriptional activity (under both constitutive and stressed conditions) may be partially dependent on the local topology of the DNA-binding domain. In addition, the DNA-binding domain may mediate key interactions with ancillary factors and/or other intramolecular regulatory regions in order to modulate the complex regulation of HSF's transcriptional activity.
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Affiliation(s)
- A L Bulman
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, 422 Curie Blvd., Philadelphia, PA 19104, USA
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38
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Chinappi I, Sánchez Crispín JA. [Production of Kluyveromices fragilis biomass in deproteinized milk whey]. Acta Cient Venez 2001; 51:223-30. [PMID: 11460792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The milk whey from a mature cheese factory deproteinised by acid thermic coagulation (pH 4.5 and 90 degrees C), provides a good culture media for the production of Kluyveromices fragilis biomass. The optimal experimental conditions for the maximal production of biomass were established by using fermenters with different capacity and design. For lactose concentration of 15 g/l, pH 4.5, 30 degrees C and aireation between 0.25 and 1 VVM, the duplication time was below two hours and 98% of the lactose was consumed. The obtained yield in dried weight was between 36 and 49% (g biomass/g lactose). The biomass (without broken cell) contain 46% protein on dry base and showed an "in vitro" digestibility of 65%. The organic mass decreased 80% after 12 hour of fermentation. This process eliminates a polluting agent and simultaneously, produces a biomass that could have industrial use as a protein complement in feeds.
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Affiliation(s)
- I Chinappi
- Laboratorio de Insumos Biológicos PROULA, Universidad de los Andes Zona Industrial La Alegría Lagunillas-Estado Mérida
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39
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Siderius M, Kolen CP, van Heerikhuizen H, Mager WH. Candidate osmosensors from Candida utilis and Kluyveromyces lactis: structural and functional homology to the Sho1p putative osmosensor from Saccharomyces cerevisiae. Biochim Biophys Acta 2000; 1517:143-7. [PMID: 11118628 DOI: 10.1016/s0167-4781(00)00231-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In Saccharomyces cerevisiae, increases in external osmolarity evoke osmostress-induced signalling via the HOG MAP kinase pathway. One of the upstream components of this signal transduction route is the putative osmosensor, Sho1p. With the aim to elucidate the molecular basis of osmosensing in budding yeast, we have cloned SHO1 homologues from Candida utilis and Kluyveromyces lactis which allowed determination of conserved domains of Sho1p. Results obtained from sequence comparisons, confirmed the importance of the transmembrane domains and the SH3 domain for Sho1p function. The K. lactis and S. cerevisiae Sho1p show the highest degree of homology, the isoform from C. utilis is a shorter protein. SHO1 from C. utilis, however, did complement the osmosensitivity of the sho1ssk2ssk22 strain by restoring HOG pathway function, since Hog1p dual phosphorylation after high osmotic challenge was restored in this strain after transformation with a plasmid bearing this SHO1 homologue.
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Affiliation(s)
- M Siderius
- Department of Biochemistry and Molecular Biology, IMBW, Biocentrum Amsterdam, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
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40
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Hardy JA, Nelson HC. Proline in alpha-helical kink is required for folding kinetics but not for kinked structure, function, or stability of heat shock transcription factor. Protein Sci 2000; 9:2128-41. [PMID: 11305238 PMCID: PMC2144482 DOI: 10.1110/ps.9.11.2128] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The DNA-binding domain of the yeast heat shock transcription factor (HSF) contains a strictly conserved proline that is at the center of a kink. To define the role of this conserved proline-centered kink, we replaced the proline with a number of other residues. These substitutions did not diminish the ability of the full-length protein to support growth of yeast or to activate transcription, suggesting that the proline at the center of the kink is not conserved for function. The stability of the isolated mutant DNA-binding domains was unaltered from the wild-type, so the proline is not conserved to maintain the stability of the protein. The crystal structures of two of the mutant DNA-binding domains revealed that the helices in the mutant proteins were still kinked after substitution of the proline, suggesting that the proline does not cause the alpha-helical kink. So why are prolines conserved in this and the majority of other kinked alpha-helices if not for structure, function, or stability? The mutant DNA-binding domains are less soluble than wild-type when overexpressed. In addition, the folding kinetics, as measured by stopped-flow fluorescence, is faster for the mutant proteins. These two results support the premise that the presence of the proline is critical for the folding pathway of HSF's DNA-binding domain. The finding may also be more general and explain why kinked helices maintain their prolines.
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Affiliation(s)
- J A Hardy
- Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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41
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Abstract
A simple procedure for isolating yeast DNA suitable for use as a template for PCR amplification is described. SDS treatment alone is sufficient for extraction of chromosomal DNA from yeast cells. Cells of a yeast colony are suspended in a small volume (about 20 microL) of a 0.25% SDS solution, mixed vigorously and centrifuged. The supernatant can be directly used as a template after dilution to give an SDS concentration of less than 0.01% in the final PCR mixture.
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Affiliation(s)
- R Akada
- Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi University, Ube, Japan.
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42
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Izgü F, Altinbay D, Sağiroğlu AK. Isolation and characterization of the K6 type yeast killer protein. Microbios 1999; 99:161-72. [PMID: 10581728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The optimum production of K6 type yeast killer protein by Kluyveromyces fragilis NCYC 587 occurred at pH 4.0-4.4 and at 22-24 degrees C in a killer-zone assay test. The K6 killer protein was concentrated by acetone precipitation of the culture supernatant and purified by native polyacrylamide rod gel electrophoresis. The protein migrated as a single band on discontinuous gradient SDS polyacrylamide gel electrophoresis and had a molecular weight of 42,313. The isoelectric point of the K6 type protein was determined at pH 5.97 by high voltage vertical polyacrylamide gel electrofocusing. Western blot analysis revealed that the K6 killer toxin was a nonglycosylated protein.
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Affiliation(s)
- F Izgü
- Department of Biological Sciences, Faculty of Science and Arts, Middle East Technical University, Ankara, Turkey
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43
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Viola AM, Lodi T, Ferrero I. A Klaac null mutant of Kluyveromyces lactis is complemented by a single copy of the Saccharomyces cerevisiae AAC1 gene. Curr Genet 1999; 36:29-36. [PMID: 10447592 DOI: 10.1007/s002940050469] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The KlAAC gene, encoding the ADP/ATP carrier in Kluveromyces lactis, has previously been cloned by complementation of the op1(aac2) mutation of Saccharomyces cerevisiae. We examined the effect of a null mutation of this gene on the phenotype of K. lactis. The consequence of this mutation was found to be multiple. The mutant was respiratory deficient, had an undetectable level of cytochrome a-a3 and b and did not grow on glycerol. The mitochondrial D-lactate ferricytochrome c oxidoreductase activity, as well as the lactate-induced transcription of its gene, KlDLD, was severely reduced. Furthermore, the mutant was unable to grow on galactose, maltose and raffinose. Transcript analysis showed that KlAAC was the only ADP/ATP carrier gene present in K. lactis. The Klaac mutation was fully complemented not only by AAC2, the major gene for the ADP/ATP carrier in S. cerevisiae, but also by AAC1, a gene which is poorly expressed in S. cerevisiae. AAC1 introduced in K. lactis was transcribed to a high level consistent with normal growth on glycerol being restored in the transformed mutant. KlAAC was not subject to control by KlHap2, in contrast to AAC2 which is regulated by the Hap2 complex in S. cerevisiae.
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Affiliation(s)
- A M Viola
- Institute of Genetics, University of Parma, Parco Area delle Scienze 11/A, I-43100 Parma, Italy.
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44
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Abstract
The 1.75 A crystal structure of the Kluyveromyces lactis heat shock transcription factor (HSF) DNA-binding domain (DBD) complexed with DNA reveals a protein-DNA interface with few direct major groove contacts and a number of phosphate backbone contacts that are primarily water-mediated interactions. The DBD, a 'winged' helix-turn-helix protein, displays a novel mode of binding in that the 'wing' does not contact DNA like all others of that class. Instead, the monomeric DBD, which crystallized as a symmetric dimer to a pair of nGAAn inverted repeats, uses the 'wing' to form part of the protein-protein contacts. This dimer interface is likely important for increasing the DNA-binding specificity and affinity of the trimeric form of HSF, as well as for increasing cooperativity between adjacent trimers.
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Affiliation(s)
- O Littlefield
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3206, USA
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45
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Belloch C, Barrio E, García MD, Querol A. Phylogenetic reconstruction of the yeast genus Kluyveromyces: restriction map analysis of the 5.8S rRNA gene and the two ribosomal internal transcribed spacers. Syst Appl Microbiol 1998; 21:266-73. [PMID: 9704113 DOI: 10.1016/s0723-2020(98)80032-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We have constructed restriction site maps of the 5.8S rRNA gene and two ITS regions in 60 strains of Kluyveromyces genus. We test the value of this region as a phylogenetic indicator, and its possible use as a fast and easy method to identify species of this genus. Despite some minor incongruences, our results are in good agreement with previous phylogenetic reconstructions based on the 18S rRNA gene sequencing (Cai et al., 1996; James et al., 1997). A highly significant monophyletic group was formed by K. lactis, K. marxianus, K. aestuarii, K. dobzhanskii and K. wickerhamii, which should be considered the true Kluyveromyces genus. The other species of the genus were grouped with lower bootstrap levels. Finally, the restriction map showed by three K. lactis strains, previously identified as K. marxianus var. drosophilarum, could be interpreted as indicatory of the possible existence of different species.
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Affiliation(s)
- C Belloch
- Colección Española de Cultivos Tipo (CECT), Spain
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46
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Abstract
The Kluyveromyces lactis HIS4 gene was cloned by complementation of a Saccharomyces cerevisiae his4 mutant. Sequence analysis revealed a 2388 bp open reading frame encoding a single polypeptide predicted to encompass three distinct enzymatic activities (phosphoribosyl-AMP cyclohydrolase, phosphoribosyl-ATP pyrophosphohydrolase and histidinol dehydrogenase). This structural organization is strikingly similar to that of the His4 proteins from S. cerevisiae and Pichia pastoris. Transcript analysis detected a single mRNA species of 2.5 kb.
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Affiliation(s)
- M A Freire-Picos
- Departamento de Biologia Celular y Molecular, Facultad de Ciencias, Universidad de La Coruña, Spain
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47
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Furui J, Uegaki K, Yamazaki T, Shirakawa M, Swindells MB, Harada H, Taniguchi T, Kyogoku Y. Solution structure of the IRF-2 DNA-binding domain: a novel subgroup of the winged helix-turn-helix family. Structure 1998; 6:491-500. [PMID: 9562558 DOI: 10.1016/s0969-2126(98)00050-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The transcription of interferon (IFN) and IFN-inducible genes is mainly regulated by the interferon regulatory factor (IRF) family of proteins, which recognize a unique AAGTGA hexamer repeat motif in the regulatory region of IFN genes. A DNA-binding domain of approximately 100 amino acids has been commonly found in the IRF family of proteins, but it has no sequence homology to known DNA-binding motifs. Elucidation of the structures of members of the IRF family is therefore useful to the understanding of the regulation and evolution of the immune system at the structural level. RESULTS The solution structure of the DNA-binding domain of interferon regulatory factor-2 (IRF-2) has been determined by NMR spectroscopy. It is composed of a four-stranded antiparallel beta sheet and three alpha helices, and its global fold is similar to those of the winged helix-turn-helix (wHTH) family of proteins. A long loop (Pro37-Asp51) is found immediately before the HTH motif, which is not found in other wHTH proteins. The NMR signals of residues in this long loop, as well as the second helix of the HTH motif, are strongly affected upon the addition of the hexamer repeat DNA, suggesting that these structural elements participate in DNA recognition and binding. CONCLUSIONS The structural similarity of the DNA-binding domain of IRF-2 with those of proteins in the wHTH family shows that the IRF proteins belong to the wHTH family, even though there is no apparent sequence homology among proteins of the two families. The sequential structure alignment program (SSAP) shows that IRF-2 has a slightly different structure from typical wHTH proteins, mainly in the orientation of helix 2. The IRF family of proteins should therefore be categorized into a subfamily of the wHTH family. The evidence here implies that the evolutional pathway of the IRF family is distinct from that of the other wHTH proteins, in other words, the immune system diverged from an evolutional stem at an early stage.
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Affiliation(s)
- J Furui
- Institute for Protein Research, Osaka University, Suita, Osaka, 565, Japan
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48
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Svitel J, Curilla O, Tkác J. Microbial cell-based biosensor for sensing glucose, sucrose or lactose. Biotechnol Appl Biochem 1998; 27:153-8. [PMID: 9569611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Biosensors for the determination of glucose, sucrose and lactose were based on a Clark-type oxygen electrode covered with a membrane containing microbial cells. The glucose-sensing membrane was prepared with intact cells of Gluconobacter oxydans immobilized in gelatin cross-linked with glutardialdehyde. The disaccharide-sensing membranes were prepared by co-immobilization of G. oxydans with cells of Saccharomyces cerevisiae containing invertase for sucrose determination and with permeabilized cells of Kluyveromyces marxianus containing beta-galactosidase for lactose determination. The strain of G. oxydans that we used was able to oxidize both anomers of glucose at the same rate; there was therefore no need for mutarotase co-immobilization in disaccharide-sensing membranes. The sensitivity of glucose sensor was 50 nA/mM, the range of the calibration curve was 0-0.8 mM, the response time was 2 min, and the response after 1 week of storage was 62% of the initial response. The parameters of the disaccharide sensors were similar: linear range of calibration curve up to 4 mM, response time 5 min. The activities of the sensors after 1 week of storage at ambient temperature were in the range 50-65% of the initial activity.
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Affiliation(s)
- J Svitel
- Biotechnology Department, Technical University, Bratislava, Slovak Republic
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49
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Abstract
Spt3 of Saccharomyces cerevisiae is a factor required for normal transcription from particular RNA polymerase II-dependent promoters. As a step towards analysing Spt3 structure-function relationships, we have identified and studied Spt3 homologues from three other yeasts: Kluyveromyces lactis, Clavispora opuntiae and Schizosaccharomyces pombe. Alignment of their predicted amino acid sequences shows an overall identity of 30% between all four homologues and suggests that three conserved domains are present in Spt3. When tested for function in S. cerevisiae, K. lactis SPT3 was shown to fully complement and S. pombe SPT3 to partially complement an spt3 delta mutation. These data demonstrate that Spt3 is functionally conserved among distantly related yeasts.
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Affiliation(s)
- J M Madison
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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Ramanandraibe E, Younsi M, Coulon J, Loppinet V, Hakkou A, Bonaly R. Implication of cell wall constituents in the sensitivity of Kluyveromyces lactis strains to amphotericin B. Res Microbiol 1998; 149:109-18. [PMID: 9766214 DOI: 10.1016/s0923-2508(98)80026-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In Kluyveromyces lactis, the cell wall compositions of Kl (ATCC 96897), a wild sensitive strain, and Klm (ATCC 96896), a strain resistant to amphotericin B (AmB), were shown to be very different, since the walls in the latter were significantly enriched in hexosamine, but had a reduced content in phosphate and amino acid. In both strains, the cell walls limited their sensitivity to this antifungal agent. The absence of cell wall increased the sensitivity of the cells to this polyene by 5 to 10-fold. When the cells were treated with enzymes such as pronase and chitinase in order to change the cell wall structure just before inoculation, the yeasts appeared more resistant to the antibiotic. However, treatments with chymopapain and phospholipase C did not significantly change the sensitivity of the two strains to this agent. Cells treated with acid phosphatase displayed a longer lag phase than the control cells. In addition, when cultured in the presence of AmB, the cells were less sensitive to this agent. The present results reveal that both a change in the ionic charges of the cell wall and an alteration in the cell wall structure modified the sensitivity of these yeast strains to AmB.
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Affiliation(s)
- E Ramanandraibe
- Université Henri Poincaré, Faculté de Pharmacie, Laboratoire de Biochimie microbienne, Nancy, France
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