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Assad-Bustillos M, Cázares-Godoy A, Devezeaux de Lavergne M, Schmitt C, Hartmann C, Windhab E. Assessment of the interactions between pea and salivary proteins in aqueous dispersions. INNOV FOOD SCI EMERG 2023. [DOI: 10.1016/j.ifset.2023.103290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Fu B, Brown C, Mäler L. Expression and Purification of DGD2, a Chloroplast Outer Membrane-Associated Glycosyltransferase for Galactolipid Synthesis. Biochemistry 2020; 59:999-1009. [PMID: 32067450 DOI: 10.1021/acs.biochem.0c00028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Galactolipids are characteristic lipids of the photosynthetic membranes. They are highly enriched in the chloroplast and are present in photosystem structures. There are two major types of galactolipids, i.e., monogalactosyldiacylglycerol and digalactosyldiacylglycerol (DGDG) in chloroplastic membranes, which amount to ∼50 and ∼20 mol % of the total chloroplast lipids, respectively. Under phosphate-limiting conditions, the amount of DGDG increases dramatically for rescuing phosphate from phospholipids. In Arabidopsis thaliana, the gene digalactosyldiacylglycerol synthase 2 (DGD2) encodes a membrane-associated glycosyltransferase. The gene expression is highly responsive to phosphate starvation and is significantly upregulated in this case. To understand the molecular mechanism of DGD2, we established a protocol for DGD2 expression and purification in an Escherichia coli-based system. The work involved optimization of the expression condition and the purification protocol and a careful selection of buffer additives. It was found that a removal of around 70 C-terminal residues was necessary to produce a homogeneous monomeric protein sample with high purity, which was highly active. The purified sample was characterized by an activity assay for enzyme kinetics in which a range of membrane mimetics with different lipid compositions were used. The results demonstrate that DGD2 activity is stimulated by the presence of negatively charged lipids, which highlight the importance of the membrane environment in modulating the enzyme's activity. The study also paves way for future biophysical and structural studies of the enzyme.
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Affiliation(s)
- Biao Fu
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Christian Brown
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lena Mäler
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Department of Chemistry, University of Umeå, SE-901 87 Umeå, Sweden
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Gruber JD, Chen W, Parnham S, Beauchesne K, Moeller P, Flume PA, Zhang YM. The role of 2,4-dihydroxyquinoline (DHQ) in Pseudomonas aeruginosa pathogenicity. PeerJ 2016; 4:e1495. [PMID: 26788419 PMCID: PMC4715436 DOI: 10.7717/peerj.1495] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/22/2015] [Indexed: 11/20/2022] Open
Abstract
Bacteria synchronize group behaviors using quorum sensing, which is advantageous during an infection to thwart immune cell attack and resist deleterious changes in the environment. In Pseudomonas aeruginosa, the Pseudomonas quinolone signal (Pqs) quorum-sensing system is an important component of an interconnected intercellular communication network. Two alkylquinolones, 2-heptyl-4-quinolone (HHQ) and 2-heptyl-3-hydroxy-4-quinolone (PQS), activate transcriptional regulator PqsR to promote the production of quinolone signals and virulence factors. Our work focused on the most abundant quinolone produced from the Pqs system, 2,4-dihydroxyquinoline (DHQ), which was shown previously to sustain pyocyanin production and antifungal activity of P. aeruginosa. However, little is known about how DHQ affects P. aeruginosa pathogenicity. Using C. elegans as a model for P. aeruginosa infection, we found pqs mutants only able to produce DHQ maintained virulence towards the nematodes similar to wild-type. In addition, DHQ-only producing mutants displayed increased colonization of C. elegans and virulence factor production compared to a quinolone-null strain. DHQ also bound to PqsR and activated the transcription of pqs operon. More importantly, high extracellular concentration of DHQ was maintained in both aerobic and anaerobic growth. High levels of DHQ were also detected in the sputum samples of cystic fibrosis patients. Taken together, our findings suggest DHQ may play an important role in sustaining P. aeruginosa pathogenicity under oxygen-limiting conditions.
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Affiliation(s)
- Jordon D Gruber
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Wei Chen
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Stuart Parnham
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
| | - Kevin Beauchesne
- Natural Products Chemistry, National Ocean Service , Charleston, SC , United States
| | - Peter Moeller
- Natural Products Chemistry, National Ocean Service , Charleston, SC , United States
| | - Patrick A Flume
- Department of Medicine, Medical University of South Carolina , Charleston, SC , United States
| | - Yong-Mei Zhang
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina , Charleston, SC , United States
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Ge C, Gómez-Llobregat J, Skwark MJ, Ruysschaert JM, Wieslander A, Lindén M. Membrane remodeling capacity of a vesicle-inducing glycosyltransferase. FEBS J 2014; 281:3667-84. [PMID: 24961908 DOI: 10.1111/febs.12889] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/21/2014] [Accepted: 06/19/2014] [Indexed: 11/28/2022]
Abstract
Intracellular vesicles are abundant in eukaryotic cells but absent in the Gram-negative bacterium Escherichia coli. However, strong overexpression of a monotopic glycolipid-synthesizing enzyme, monoglucosyldiacylglycerol synthase from Acholeplasma laidlawii (alMGS), leads to massive formation of vesicles in the cytoplasm of E. coli. More importantly, alMGS provides a model system for the regulation of membrane properties by membrane-bound enzymes, which is critical for maintaining cellular integrity. Both phenomena depend on how alMGS binds to cell membranes, which is not well understood. Here, we carry out a comprehensive investigation of the membrane binding of alMGS by combining bioinformatics methods with extensive biochemical studies, structural modeling and molecular dynamics simulations. We find that alMGS binds to the membrane in a fairly upright manner, mainly by residues in the N-terminal domain, and in a way that induces local enrichment of anionic lipids and a local curvature deformation. Furthermore, several alMGS variants resulting from substitution of residues in the membrane anchoring segment are still able to generate vesicles, regardless of enzymatic activity. These results clarify earlier theories about the driving forces for vesicle formation, and shed new light on the membrane binding properties and enzymatic mechanism of alMGS and related monotopic GT-B fold glycosyltransferases.
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Affiliation(s)
- Changrong Ge
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Sweden; Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Belgium; Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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Rösner HI, Kragelund BB. Structure and dynamic properties of membrane proteins using NMR. Compr Physiol 2013; 2:1491-539. [PMID: 23798308 DOI: 10.1002/cphy.c110036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Integral membrane proteins are one of the most challenging groups of macromolecules despite their apparent conformational simplicity. They manage and drive transport, circulate information, and participate in cellular movements via interactions with other proteins and through intricate conformational changes. Their structural and functional decoding is challenging and has imposed demanding experimental development. Solution nuclear magnetic resonance (NMR) spectroscopy is one of the techniques providing the capacity to make a significant difference in the deciphering of the membrane protein structure-function paradigm. The method has evolved dramatically during the last decade resulting in a plethora of new experiments leading to a significant increase in the scientific repertoire for studying membrane proteins. Besides solving the three-dimensional structures using state-of-the-art approaches, a large variety of developments of well-established techniques are available providing insight into membrane protein flexibility, dynamics, and interactions. Inspired by the speed of development in the application of new strategies, by invention of methods to measure solvent accessibility and describe low-populated states, this review seeks to introduce the vast possibilities solution NMR can offer to the study of membrane protein structure-function analyses with special focus on applicability.
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Affiliation(s)
- Heike I Rösner
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Ariöz C, Ye W, Bakali A, Ge C, Liebau J, Götzke H, Barth A, Wieslander Å, Mäler L. Anionic Lipid Binding to the Foreign Protein MGS Provides a Tight Coupling between Phospholipid Synthesis and Protein Overexpression in Escherichia coli. Biochemistry 2013; 52:5533-44. [DOI: 10.1021/bi400616n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Candan Ariöz
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Weihua Ye
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Amin Bakali
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Changrong Ge
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Jobst Liebau
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Hansjörg Götzke
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Andreas Barth
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Åke Wieslander
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
| | - Lena Mäler
- Center for Biomembrane
Research, Department of Biochemistry
and Biophysics, Stockholm University, SE-106
91 Stockholm, Sweden
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Van Pham ST, Engman H, Dahlgren LG, Cornvik T, Eshaghi S. A systematic approach to isolate mono-disperse membrane proteins - purification of zinc transporter ZntB. Protein Expr Purif 2010; 72:48-54. [PMID: 20159043 DOI: 10.1016/j.pep.2010.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 02/11/2010] [Accepted: 02/11/2010] [Indexed: 10/19/2022]
Abstract
Obtaining mono-disperse and stable protein is a requirement for successful structural and biochemical investigation of proteins. For membrane proteins, such preparation is one of the major hurdles, which consequently has contributed to the slow progress in studying them. During the past few years, many screening methods have been developed to make studies of membrane proteins more efficient. Despite these advances, many membrane proteins remain challenging to even isolate in a stable and homogeneous form. The bacterial zinc transporter ZntB is such a protein, for which no isolation procedure has been reported. Here, we present a systematic approach to obtain homogeneous and mono-disperse zinc transporter ZntB in quantities sufficient for structural and biochemical studies. Important aspects of this study that can be applied to other membrane proteins are also discussed.
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Affiliation(s)
- Sally Thanh Van Pham
- Centre for Biomedical Structural Biology, School of Biological Sciences, Nanyang Technological University, Singapore
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Eriksson HM, Wessman P, Ge C, Edwards K, Wieslander Å. Massive formation of intracellular membrane vesicles in Escherichia coli by a monotopic membrane-bound lipid glycosyltransferase. J Biol Chem 2009; 284:33904-14. [PMID: 19767390 PMCID: PMC2797161 DOI: 10.1074/jbc.m109.021618] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 09/17/2009] [Indexed: 01/07/2023] Open
Abstract
The morphology and curvature of biological bilayers are determined by the packing shapes and interactions of their participant molecules. Bacteria, except photosynthetic groups, usually lack intracellular membrane organelles. Strong overexpression in Escherichia coli of a foreign monotopic glycosyltransferase (named monoglycosyldiacylglycerol synthase), synthesizing a nonbilayer-prone glucolipid, induced massive formation of membrane vesicles in the cytoplasm. Vesicle assemblies were visualized in cytoplasmic zones by fluorescence microscopy. These have a very low buoyant density, substantially different from inner membranes, with a lipid content of > or = 60% (w/w). Cryo-transmission electron microscopy revealed cells to be filled with membrane vesicles of various sizes and shapes, which when released were mostly spherical (diameter approximately 100 nm). The protein repertoire was similar in vesicle and inner membranes and dominated by the glycosyltransferase. Membrane polar lipid composition was similar too, including the foreign glucolipid. A related glycosyltransferase and an inactive monoglycosyldiacylglycerol synthase mutant also yielded membrane vesicles, but without glucolipid synthesis, strongly indicating that vesiculation is induced by the protein itself. The high capacity for membrane vesicle formation seems inherent in the glycosyltransferase structure, and it depends on the following: (i) lateral expansion of the inner monolayer by interface binding of many molecules; (ii) membrane expansion through stimulation of phospholipid synthesis, by electrostatic binding and sequestration of anionic lipids; (iii) bilayer bending by the packing shape of excess nonbilayer-prone phospholipid or glucolipid; and (iv) potentially also the shape or penetration profile of the glycosyltransferase binding surface. These features seem to apply to several other proteins able to achieve an analogous membrane expansion.
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Affiliation(s)
- Hanna M. Eriksson
- From the Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm and
| | - Per Wessman
- the Department of Physical and Analytical Chemistry, Uppsala University, SE-75123 Uppsala, Sweden
| | - Changrong Ge
- From the Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm and
| | - Katarina Edwards
- the Department of Physical and Analytical Chemistry, Uppsala University, SE-75123 Uppsala, Sweden
| | - Åke Wieslander
- From the Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm and
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