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Leite JAS, Montoya CA, Loveday SM, Mullaney JA, Loo TS, McNabb WC, Roy NC. The impact of heating and drying on protease activities of ruminant milk before and after in vitro infant digestion. Food Chem 2023; 429:136979. [PMID: 37506658 DOI: 10.1016/j.foodchem.2023.136979] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023]
Abstract
This study investigated the effect of heating (63°C/30 min or 75°C/15 s) and drying (spray-drying or freeze-drying) on plasmin, cathepsin D, and elastase activities in bovine, ovine, and caprine milk, compared to non-dried raw milk counterparts. Protease activities and protein hydrolysis were assessed before and after in vitro infant digestion with or without gastric and pancreatic enzymes. At 75°C/15 s, plasmin activity in caprine and ovine milk decreased (69-75%, p<0.05), while cathepsin D activity in spray-dried bovine milk heated increased (2.8-fold, p<0.05). Plasmin and cathepsin D activities increased (<1.2-fold, p<0.05) after in vitro digestion with pancreatin, regardless of milk species. Endogenous milk enzymes hydrolyzed more proteins than gastric enzymes during gastric digestion and contributed to small intestinal digestion. In summary, milk proteases remained active after processing with effects dependent on the species of milk, and they contributed to in vitro protein hydrolysis in the stomach and small intestine.
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Affiliation(s)
- Juliana A S Leite
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand
| | - Carlos A Montoya
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand; Smart Foods & Bioproducts Innovation Centre of Excellence, AgResearch Limited, Palmerston North 4474, New Zealand
| | - Simon M Loveday
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand; Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Jane A Mullaney
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand; High-Value Nutrition National Science Challenge, Auckland 1010, New Zealand
| | - Trevor S Loo
- School of Natural Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Warren C McNabb
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand; High-Value Nutrition National Science Challenge, Auckland 1010, New Zealand
| | - Nicole C Roy
- Riddet Institute, Massey University, Palmerston North 4442, New Zealand; High-Value Nutrition National Science Challenge, Auckland 1010, New Zealand; Department of Nutrition, University of Otago, Dunedin 9016, New Zealand.
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2
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Visser DR, Loo TS, Norris GE, Parry DAD. Potential implications of the glycosylation patterns in collagen α1(I) and α2(I) chains for fibril assembly and growth. J Struct Biol 2023; 215:107938. [PMID: 36641113 DOI: 10.1016/j.jsb.2023.107938] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/13/2023]
Abstract
O-Glycosylation of hydroxylysine (Hyl) in collagen occurs at an early stage of biosynthesis before the triple-helix has formed. This simple post-translational modification (PTM) of lysine by either a galactosyl or glucosylgalactosyl moiety is highly conserved in collagens and depends on the species, type of tissue and the collagen amino acid sequence. The structural/functional reason why only specific lysines are modified is poorly understood, and has led to increased efforts to map the sites of PTMs on collagen sequences from different species and to ascertain their potential role in vivo. To investigate this, we purified collagen type I (Col1) from the skins of four animals, then used mass spectrometry and proteomic techniques to identify lysines that were oxidised, galactosylated, glucosylgalactosylated, or glycated in its mature sequence. We found 18 out of the 38 lysines in collagen type Iα1, (Col1A1) and 7 of the 30 lysines in collagen type Iα2 (Col1A2) were glycosylated. Six of these modifications had not been reported before, and included a lysine involved in crosslinking collagen molecules. A Fourier transform analysis of the positions of the glycosylated hydroxylysines showed they display a regular axial distribution with the same d-period observed in collagen fibrils. The significance of this finding in terms of the assembly of collagen molecules into fibrils and of potential restrictions on the growth of the collagen fibrils is discussed.
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Affiliation(s)
- D R Visser
- School of Natural Sciences, Massey University, New Zealand
| | - T S Loo
- School of Natural Sciences, Massey University, New Zealand
| | - G E Norris
- School of Natural Sciences, Massey University, New Zealand.
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3
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Jayawardana IA, Boland MJ, Loo TS, McNabb WC, Montoya CA. Rapid proteolysis of gluten-derived immunogenic peptides in bread by actinidin in a combined in vivo and in vitro oro-gastrointestinal digestion model. Food Funct 2022; 13:5654-5666. [PMID: 35510393 DOI: 10.1039/d1fo03740d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study aimed to determine the ability of actinidin, a cysteine protease in green kiwifruit (Actinidia deliciosa), to hydrolyse wheat proteins and gluten-derived immunogenic peptides from a commonly consumed food matrix (bread) using a combined in vivo and in vitro oro-gastrointestinal tract (GIT) model. A chewed and spat composite bolus of bread was in vitro digested with or without purified actinidin using a human gastric simulator (HGS). Gastric digestion was conducted for 150 min with gastric emptying occurring at different time points. Emptied samples were immediately digested under simulated small intestinal conditions. Gastric and small intestinal aliquots were collected to quantify peptide profiles and nine marker immunogenic peptides (by untargeted and targeted mass spectrometry, respectively), R5 epitopes (by monoclonal antibody-based competition assay), and free amino groups released by digestion (by the o-phthaldialdehyde method). There was a significant effect (P < 0.05) of actinidin and digestion time on the hydrolysis of wheat proteins and the amount of gluten R5 epitopes of that material emptying the HGS. Actinidin accelerated 1.2-fold the gastric hydrolysis of wheat proteins during the first 20 min of digestion, which was reflected in a faster (5.5 μg min-1) reduction in the evolution of R5 epitopes. Actinidin accelerated (P < 0.05) the rate of disappearance of most of the immunogenic marker peptides. For example, in the first 20 min of small intestinal digestion, the 33-mer peptide decreased (P < 0.05) 2-fold faster (0.25 vs. 0.12 μg g-1 of bread per min) in the presence of actinidin than in the control. Untargeted peptidomics showed actinidin decreased the amounts of known immunogenic peptides in the simulated small intestinal digestion. These findings demonstrated that actinidin accelerates the hydrolysis of wheat proteins and known gluten immunogenic peptides in a commonly consumed food matrix (bread) in a combined in vivo and in vitro oro-GIT digestion model.
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Affiliation(s)
- Isuri A Jayawardana
- Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand. .,School of Food and Advanced Technology, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand
| | - Mike J Boland
- Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand.
| | - Trevor S Loo
- School of Fundamental Sciences, College of Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Warren C McNabb
- Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand. .,High-Value Nutrition National Science Challenge, Auckland, New Zealand.,Sustainable Nutrition Initiative, Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Carlos A Montoya
- Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand. .,Smart Foods Innovation Centre of Excellence, AgResearch Limited, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand
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4
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Hunziker L, Tarallo M, Gough K, Guo M, Hargreaves C, Loo TS, McDougal RL, Mesarich CH, Bradshaw RE. Apoplastic effector candidates of a foliar forest pathogen trigger cell death in host and non-host plants. Sci Rep 2021; 11:19958. [PMID: 34620932 PMCID: PMC8497623 DOI: 10.1038/s41598-021-99415-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/22/2021] [Indexed: 11/23/2022] Open
Abstract
Forests are under threat from pests, pathogens, and changing climate. A major forest pathogen worldwide is the hemibiotroph Dothistroma septosporum, which causes dothistroma needle blight (DNB) of pines. While D. septosporum uses effector proteins to facilitate host infection, it is currently unclear whether any of these effectors are recognised by immune receptors to activate the host immune system. Such information is needed to identify and select disease resistance against D. septosporum in pines. We predicted and investigated apoplastic D. septosporum candidate effectors (DsCEs) using bioinformatics and plant-based experiments. We discovered DsCEs that trigger cell death in the angiosperm Nicotiana spp., indicative of a hypersensitive defence response and suggesting their recognition by immune receptors in non-host plants. In a first for foliar forest pathogens, we developed a novel protein infiltration method to show that tissue-cultured pine shoots can respond with a cell death response to a DsCE, as well as to a reference cell death-inducing protein. The conservation of responses across plant taxa suggests that knowledge of pathogen-angiosperm interactions may also be relevant to pathogen-gymnosperm interactions. These results contribute to our understanding of forest pathogens and may ultimately provide clues to disease immunity in both commercial and natural forests.
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Affiliation(s)
- Lukas Hunziker
- Centre for Crop and Disease Management, Curtin University, Bentley, Perth, 6102, Australia
| | - Mariana Tarallo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Keiko Gough
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Melissa Guo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Cathy Hargreaves
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Trevor S Loo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Rebecca L McDougal
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Carl H Mesarich
- Bio-Protection Research Centre, School of Agriculture and Environment, Massey University, Palmerston North, 4474, New Zealand
| | - Rosie E Bradshaw
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand.
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5
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Harjes E, Jameson GB, Tu YH, Burr N, Loo TS, Goroncy AK, Edwards PJB, Harjes S, Munro B, Göbl C, Sattlegger E, Norris GE. Experimentally based structural model of Yih1 provides insight into its function in controlling the key translational regulator Gcn2. FEBS Lett 2020; 595:324-340. [PMID: 33156522 DOI: 10.1002/1873-3468.13990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/21/2020] [Accepted: 11/02/2020] [Indexed: 12/15/2022]
Abstract
Yeast impact homolog 1 (Yih1), or IMPACT in mammals, is part of a conserved regulatory module controlling the activity of General Control Nonderepressible 2 (Gcn2), a protein kinase that regulates protein synthesis. Yih1/IMPACT is implicated not only in many essential cellular processes, such as neuronal development, immune system regulation and the cell cycle, but also in cancer. Gcn2 must bind to Gcn1 in order to impair the initiation of protein translation. Yih1 hinders this key Gcn1-Gcn2 interaction by binding to Gcn1, thus preventing Gcn2-mediated inhibition of protein synthesis. Here, we solved the structures of the two domains of Saccharomyces cerevisiae Yih1 separately using Nuclear Magnetic Resonance and determined the relative positions of the two domains using a range of biophysical methods. Our findings support a compact structural model of Yih1 in which the residues required for Gcn1 binding are buried in the interface. This model strongly implies that Yih1 undergoes a large conformational rearrangement from a latent closed state to a primed open state to bind Gcn1. Our study provides structural insight into the interactions of Yih1 with partner molecules.
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Affiliation(s)
- Elena Harjes
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
| | - Geoffrey B Jameson
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
| | - Yi-Hsuan Tu
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Natalie Burr
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Trevor S Loo
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Alexander K Goroncy
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Patrick J B Edwards
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Stefan Harjes
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Ben Munro
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Christoph Göbl
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Evelyn Sattlegger
- Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand.,School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | - Gillian E Norris
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
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6
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Yeung JH, Shu D, Ferguson T, Altermann E, Khanum S, Gupta S, Loo TS, Sutherland-Smith AJ, Heiser A, Janssen PH, Wedlock DN. Investigation of Cell Envelope‐Associated Proteins in Rumen Methanogens as Targets for Understanding Host‐Microbe Interactions. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.08838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Dairu Shu
- Animal Health - AgResearch Grasslands
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7
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Main P, Hata T, Loo TS, Man P, Novak P, Havlíček V, Norris GE, Patchett ML. Bacteriocin ASM1 is an
O
/
S
‐diglycosylated, plasmid‐encoded homologue of glycocin F. FEBS Lett 2020; 594:1196-1206. [DOI: 10.1002/1873-3468.13708] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Patrick Main
- School of Fundamental Sciences Massey University Palmerston North New Zealand
| | - Tomomi Hata
- Department of Food and Nutritional Sciences Ochanomizu University Tokyo Japan
| | - Trevor S. Loo
- School of Fundamental Sciences Massey University Palmerston North New Zealand
| | - Petr Man
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Petr Novak
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Vladimír Havlíček
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Gillian E. Norris
- School of Fundamental Sciences Massey University Palmerston North New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery University of Auckland New Zealand
| | - Mark L. Patchett
- School of Fundamental Sciences Massey University Palmerston North New Zealand
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8
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Ahn S, Stepper J, Loo TS, Bisset SW, Patchett ML, Norris GE. Expression of Lactobacillus plantarum KW30 gcc genes correlates with the production of glycocin F in late log phase. FEMS Microbiol Lett 2019; 365:5144765. [PMID: 30364948 DOI: 10.1093/femsle/fny261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 10/24/2018] [Indexed: 12/24/2022] Open
Abstract
Antibacterial compounds known as bacteriocins are microbial inventions designed to reduce the competition for limited resources by inhibiting the growth of closely related bacteria. Glycocin F (GccF) is an unusually di-glycosylated bacteriocin produced in a lactic acid bacterium, Lactobacillus plantarum KW30 that has been shown to be resistant to extreme conditions. It is bacteriostatic rather than bactericidal, and all its post-translational modifications (a pair of nested disulfide bonds, and O-linked and S-linked N-acetylglucosamines) are required for full activity. Here, we examine a cluster of genes predicted to be responsible for GccF expression and maturation. The expression of eight genes, previously reported to make up the gcc operon, was profiled for their expression during cell culture. We found that all but one of the genes of the gcc cluster followed a pattern of expression that correlated with the stage of growth observed for the producer organism along with the increase in GccF secretion. We also found that most of the gcc genes are transcribed as a single unit. These data provide evidence that the gcc cluster genes gccABCDEF constitute a true operon for regulated GccF production, and explain the observed increase in GccF concentration that accompanies an increase in cell numbers.
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Affiliation(s)
- Soyeon Ahn
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand
| | - Judith Stepper
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand
| | - Trevor S Loo
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand
| | - Sean W Bisset
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Mark L Patchett
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand
| | - Gillian E Norris
- Institute of Fundamental Sciences, Massey University, Tennent Drive, Palmerston North 4474, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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9
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Kent LM, Loo TS, Melton LD, Mercadante D, Williams MAK, Jameson GB. Structure and Properties of a Non-processive, Salt-requiring, and Acidophilic Pectin Methylesterase from Aspergillus niger Provide Insights into the Key Determinants of Processivity Control. J Biol Chem 2015; 291:1289-306. [PMID: 26567911 DOI: 10.1074/jbc.m115.673152] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Indexed: 12/17/2022] Open
Abstract
Many pectin methylesterases (PMEs) are expressed in plants to modify plant cell-wall pectins for various physiological roles. These pectins are also attacked by PMEs from phytopathogens and phytophagous insects. The de-methylesterification by PMEs of the O6-methyl ester groups of the homogalacturonan component of pectin, exposing galacturonic acids, can occur processively or non-processively, respectively, describing sequential versus single de-methylesterification events occurring before enzyme-substrate dissociation. The high resolution x-ray structures of a PME from Aspergillus niger in deglycosylated and Asn-linked N-acetylglucosamine-stub forms reveal a 10⅔-turn parallel β-helix (similar to but with less extensive loops than bacterial, plant, and insect PMEs). Capillary electrophoresis shows that this PME is non-processive, halophilic, and acidophilic. Molecular dynamics simulations and electrostatic potential calculations reveal very different behavior and properties compared with processive PMEs. Specifically, uncorrelated rotations are observed about the glycosidic bonds of a partially de-methyl-esterified decasaccharide model substrate, in sharp contrast to the correlated rotations of processive PMEs, and the substrate-binding groove is negatively not positively charged.
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Affiliation(s)
- Lisa M Kent
- From Riddet Institute and Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Trevor S Loo
- From Riddet Institute and Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Laurence D Melton
- From Riddet Institute and School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Davide Mercadante
- From Riddet Institute and Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg, 69118 Heidelberg, Germany, and
| | - Martin A K Williams
- From Riddet Institute and Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand, MacDiarmid Institute for Advanced Materials and Nanotechnology, Palmerston North 4442, New Zealand
| | - Geoffrey B Jameson
- From Riddet Institute and Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand, MacDiarmid Institute for Advanced Materials and Nanotechnology, Palmerston North 4442, New Zealand
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10
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Doluca O, Withers JM, Loo TS, Edwards PJB, González C, Filichev VV. Interdependence of pyrene interactions and tetramolecular G4-DNA assembly. Org Biomol Chem 2015; 13:3742-8. [DOI: 10.1039/c4ob02499k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our results demonstrate the expanded capabilities of G-quadruplex DNAs for directed chromophore arrangements and show new perspectives in the design of G-quadruplexes governed by non-guanine moieties.
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Affiliation(s)
- Osman Doluca
- College of Sciences
- Institute of Fundamental Sciences
- Massey University
- 4442 Palmerston North
- New Zealand
| | - Jamie M. Withers
- College of Sciences
- Institute of Fundamental Sciences
- Massey University
- 4442 Palmerston North
- New Zealand
| | - Trevor S. Loo
- College of Sciences
- Institute of Fundamental Sciences
- Massey University
- 4442 Palmerston North
- New Zealand
| | - Patrick J. B. Edwards
- College of Sciences
- Institute of Fundamental Sciences
- Massey University
- 4442 Palmerston North
- New Zealand
| | | | - Vyacheslav V. Filichev
- College of Sciences
- Institute of Fundamental Sciences
- Massey University
- 4442 Palmerston North
- New Zealand
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11
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Crowther JM, Lassé M, Suzuki H, Kessans SA, Loo TS, Norris GE, Hodgkinson AJ, Jameson GB, Dobson RCJ. Ultra-high resolution crystal structure of recombinant caprine β-lactoglobulin. FEBS Lett 2014; 588:3816-22. [PMID: 25241165 DOI: 10.1016/j.febslet.2014.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/29/2014] [Accepted: 09/02/2014] [Indexed: 11/26/2022]
Abstract
β-Lactoglobulin (βlg) is the most abundant whey protein in the milks of ruminant animals. While bovine βlg has been subjected to a vast array of studies, little is known about the caprine ortholog. We present an ultra-high resolution crystal structure of caprine βlg complemented by analytical ultracentrifugation and small-angle X-ray scattering data. In both solution and crystalline states caprine βlg is dimeric (K(D)<5 μM); however, our data suggest a flexible quaternary arrangement of subunits within the dimer. These structural findings will provide insight into relationships among structural, processing, nutritional and immunological characteristics that distinguish cow's and goat's milk.
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Affiliation(s)
- Jennifer M Crowther
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Moritz Lassé
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Hironori Suzuki
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Sarah A Kessans
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Trevor S Loo
- Institute of Fundamental Sciences and The Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Gillian E Norris
- Institute of Fundamental Sciences and The Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Alison J Hodgkinson
- Food and Bio-based Products, AgResearch Limited, Ruakura Research Centre, Hamilton, New Zealand
| | - Geoffrey B Jameson
- Institute of Fundamental Sciences and The Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
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12
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Dave AC, Loveday SM, Anema SG, Loo TS, Norris GE, Jameson GB, Singh H. Β-lactoglobulin self-assembly: structural changes in early stages and disulfide bonding in fibrils. J Agric Food Chem 2013; 61:7817-7828. [PMID: 23848407 DOI: 10.1021/jf401084f] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bovine β-lactoglobulin (β-Lg) self-assembles into long amyloid-like fibrils when heated at 80 °C, pH 2, and low ionic strength (<0.015 mM). Heating β-Lg under fibril-forming conditions shows a lag phase before fibrils start forming. We have investigated the structural characteristics of β-Lg during the lag phase and the composition of β-Lg fibrils after their separation using ultracentrifugation. During the lag phase, the circular dichroism spectra of heated β-Lg showed rapid unfolding, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of samples showed increasing hydrolysis of β-Lg. The SDS-PAGE profiles of fibrils separated by ultra centrifugation showed that after six hours, the fibrils consisted of a few preferentially accumulated peptides. Two-dimensional SDS-PAGE under reducing and nonreducing conditions showed the presence of disulfide-bonded fragments in the fibrils. The sequences in these peptide bands were characterized by in-gel digestion electrospray ionization (ESI)-MS/MS. The composition of solubilized fibrils was also characterized by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS/MS. Both MS analyses showed that peptides in fibrils were primarily from the N-terminal region, although there was some evidence of peptides from the C-terminal part of the molecule present in the higher molecular weight gel bands. We suggest that although the N-terminal region of β-Lg is almost certainly involved in the formation of the fibrils, other peptide fragments linked through disulfide bonds may also be present in the fibrils during self-assembly.
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Affiliation(s)
- Anant C Dave
- Riddet Institute, Massey University, Private Bag 11 222, Palmerston North, New Zealand
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Mercadante D, Melton LD, Norris GE, Loo TS, Williams MAK, Dobson RCJ, Jameson GB. Bovine β-lactoglobulin is dimeric under imitative physiological conditions: dissociation equilibrium and rate constants over the pH range of 2.5-7.5. Biophys J 2012; 103:303-12. [PMID: 22853908 DOI: 10.1016/j.bpj.2012.05.041] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 05/03/2012] [Accepted: 05/15/2012] [Indexed: 10/28/2022] Open
Abstract
The oligomerization of β-lactoglobulin (βLg) has been studied extensively, but with somewhat contradictory results. Using analytical ultracentrifugation in both sedimentation equilibrium and sedimentation velocity modes, we studied the oligomerization of βLg variants A and B over a pH range of 2.5-7.5 in 100 mM NaCl at 25°C. For the first time, to our knowledge, we were able to estimate rate constants (k(off)) for βLg dimer dissociation. At pH 2.5 k(off) is low (0.008 and 0.009 s(-1)), but at higher pH (6.5 and 7.5) k(off) is considerably greater (>0.1 s(-1)). We analyzed the sedimentation velocity data using the van Holde-Weischet method, and the results were consistent with a monomer-dimer reversible self-association at pH 2.5, 3.5, 6.5, and 7.5. Dimer dissociation constants K(D)(2-1) fell close to or within the protein concentration range of ∼5 to ∼45 μM, and at ∼45 μM the dimer predominated. No species larger than the dimer could be detected. The K(D)(2-1) increased as |pH-pI| increased, indicating that the hydrophobic effect is the major factor stabilizing the dimer, and suggesting that, especially at low pH, electrostatic repulsion destabilizes the dimer. Therefore, through Poisson-Boltzmann calculations, we determined the electrostatic dimerization energy and the ionic charge distribution as a function of ionic strength at pH above (pH 7.5) and below (pH 2.5) the isoelectric point (pI∼5.3). We propose a mechanism for dimer stabilization whereby the added ionic species screen and neutralize charges in the vicinity of the dimer interface. The electrostatic forces of the ion cloud surrounding βLg play a key role in the thermodynamics and kinetics of dimer association/dissociation.
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Stepper J, Shastri S, Loo TS, Preston JC, Novak P, Man P, Moore CH, Havlíček V, Patchett ML, Norris GE. Cysteine S-glycosylation, a new post-translational modification found in glycopeptide bacteriocins. FEBS Lett 2011; 585:645-50. [PMID: 21251913 DOI: 10.1016/j.febslet.2011.01.023] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 01/13/2011] [Accepted: 01/13/2011] [Indexed: 11/12/2022]
Abstract
O-Glycosylation is a ubiquitous eukaryotic post-translational modification, whereas early reports of S-linked glycopeptides have never been verified. Prokaryotes also glycosylate proteins, but there are no confirmed examples of sidechain glycosylation in ribosomal antimicrobial polypeptides collectively known as bacteriocins. Here we show that glycocin F, a bacteriocin secreted by Lactobacillus plantarum KW30, is modified by an N-acetylglucosamine β-O-linked to Ser18, and an N-acetylhexosamine S-linked to C-terminal Cys43. The O-linked N-acetylglucosamine is essential for bacteriostatic activity, and the C-terminus is required for full potency (IC(50) 2 nM). Genomic context analysis identified diverse putative glycopeptide bacteriocins in Firmicutes. One of these, the reputed lantibiotic sublancin, was shown to contain a hexose S-linked to Cys22.
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Affiliation(s)
- Judith Stepper
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
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Ponniah K, Loo TS, Edwards PJB, Pascal SM, Jameson GB, Norris GE. The production of soluble and correctly folded recombinant bovine beta-lactoglobulin variants A and B in Escherichia coli for NMR studies. Protein Expr Purif 2009; 70:283-9. [PMID: 20018245 DOI: 10.1016/j.pep.2009.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/04/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022]
Abstract
The production of soluble and correctly folded eukaryotic proteins in prokaryotic systems has always been hampered by the difference in or lack of cell machinery responsible for folding, post-translation modification and secretion of the proteins involved. In the case of bovine beta-lactoglobulin (BLG), a major cow's milk allergen and a protein widely used for protein folding studies, a eukaryotic yeast expression system has been the preferred choice of many researchers, particularly for the production of isotopically labeled protein required for NMR studies. Although this system yields high amounts of recombinant protein, the BLG produced is usually associated with extracellular polysaccharides, which is problematic for NMR analysis. In our study we show that when co-expressed with the signal-sequence-less disulfide bond isomerase (Delta ssDsbC) in the dual expression vector, pETDUET-1, both BLG A and BLG B can be reproducibly produced in a soluble form. Expression was carried out in Escherichia coli Origami(DE3), a trxB/gor mutant for thioredoxin- and glutathione reductase, which allows for proper formation of disulfide bonds in the cytoplasm. The protein was purified by anion exchange chromatography followed by salting-out at low pH and size exclusion chromatography. Our expression system is able to consistently produce milligram quantities of correctly folded BLG A and B with no additional amino acid residues at the N-terminus, except for a methionine. (15)N-labeled BLG A and B, prepared and purified using this method, produced HSQC spectra typical of native bovine BLG.
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Affiliation(s)
- Komala Ponniah
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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Affiliation(s)
- T E Finucane
- Johns Hopkins Geriatrics Center, Baltimore, MD 21224, USA.
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