@article{AlbrechtGrevePuschetal.1998, author = {Albrecht, Tanja and Greve, Burkhard and Pusch, Kerstin and Koßmann, Jens and Buchner, Peter and Wobus, Ulrich and Steup, Martin}, title = {Homo- and Heterodimers of Pho1-Type Phosphorylase Isoforms in Solanum tuberosum L. as Revealed by Sequence- Specific Antibodies}, year = {1998}, language = {en} } @article{AlbrechtHaebelKochetal.2004, author = {Albrecht, Tanja and Haebel, Sophie and Koch, Anke and Krause, Ulrike and Eckermann, Nora and Steup, Martin}, title = {Yeast glycogenin (Glg2p) produced in Escherichia coli is simultaneously glucosylated at two vicinal tyrosin residues but results in a reduced bacterial glycogen accumulation}, year = {2004}, abstract = {Saccharomyces cerevisiae possesses two glycogenin isoforms (designated as Glg1p and Glg2p) that both contain a conserved tyrosine residue, Tyr232. However, Glg2p possesses an additional tyrosine residue, Tyr230 and therefore two potential autoglucosylation sites. Glucosylation of Glg2p was studied using both matrix-assisted laser desorption ionization and electrospray quadrupole time of flight mass spectrometry. Glg2p, carrying a C-terminal (His(6)) tag, was produced in Escherichia coli and purified. By tryptic digestion and reversed phase chromatography a peptide (residues 219-246 of the complete Glg2p sequence) was isolated that contained 4-25 glucosyl residues. Following incubation of Glg2p with UDPglucose, more than 36 glucosyl residues were covalently bound to this peptide. Using a combination of cyanogen bromide cleavage of the protein backbone, enzymatic hydrolysis of glycosidic bonds and reversed phase chromatography, mono- and diglucosylated peptides having the sequence PNYGYQSSPAM were generated. MS/MS spectra revealed that glucosyl residues were attached to both Tyr232 and Tyr230 within the same peptide. The formation of the highly glucosylated eukaryotic Glg2p did not favour the bacterial glycogen accumulation. Under various experimental conditions Glg2p-producing cells accumulated approximately 30\% less glycogen than a control transformed with a Glg2p lacking plasmid. The size distribution of the glycogen and extractable activities of several glycogen-related enzymes were essentially unchanged. As revealed by high performance anion exchange chromatography, the intracellular maltooligosaccharide pattern of the bacterial cells expressing the functional eukaryotic transgene was significantly altered. Thus, the eukaryotic glycogenin appears to be incompatible with the bacterial initiation of glycogen biosynthesis}, language = {en} } @article{AlbrechtKochLodeetal.2001, author = {Albrecht, Tanja and Koch, Anke and Lode, Anja and Greve, Burkhard and Schneider-Mergener, Jens and Steup, Martin}, title = {Plastidic (Pho1-type) phosphorylase isoforms in potato (Solanum tuberosum L.) plants : expression analysis and immunochemical characterization}, year = {2001}, language = {en} } @article{BallLienardWattebledetal.2003, author = {Ball, Steven G. and Li{\´e}nard, Luc and Wattebled, Fabrice and Steup, Martin and Hicks, Glenn and d'Hulst, Christophe}, title = {Defining the functions of maltodextrin active enzymes in starch metabolism in the unicellular alga Chlamydomonas reinhardtii}, year = {2003}, language = {en} } @misc{CencilNitschkeSteupetal.2014, author = {Cencil, Ugo and Nitschke, Felix and Steup, Martin and Minassian, Berge A. and Colleoni, Christophe and Ball, Steven G.}, title = {Transition from glycogen to starch metabolism in Archaeplastida}, series = {Trends in plant science}, volume = {19}, journal = {Trends in plant science}, number = {1}, publisher = {Elsevier}, address = {London}, issn = {1360-1385}, doi = {10.1016/j.tplants.2013.08.004}, pages = {18 -- 28}, year = {2014}, abstract = {In this opinion article we propose a scenario detailing how two crucial components have evolved simultaneously to ensure the transition of glycogen to starch in the cytosol of the Archaeplastida last common ancestor: (i) the recruitment of an enzyme from intracellular Chlamydiae pathogens to facilitate crystallization of alpha-glucan chains; and (ii) the evolution of novel types of polysaccharide (de)phosphorylating enzymes from preexisting glycogen (de)phosphorylation host pathways to allow the turnover of such crystals. We speculate that the transition to starch benefitted Archaeplastida in three ways: more carbon could be packed into osmotically inert material; the host could resume control of carbon assimilation from the chlamydial pathogen that triggered plastid endosymbiosis; and cyanobacterial photosynthate export could be integrated in the emerging Archaeplastida.}, language = {en} } @misc{CisekTokarzKontenisetal.2018, author = {Cisek, Richard and Tokarz, Danielle and Kontenis, Lukas and Barzda, Virginijus and Steup, Martin}, title = {Polarimetric second harmonic generation microscopy}, series = {Starch-Starke}, volume = {70}, journal = {Starch-Starke}, number = {1-2}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0038-9056}, doi = {10.1002/star.201700031}, pages = {15}, year = {2018}, abstract = {Second harmonic generation (SHG) is a nonlinear optical process that inherently generates signal in non-centrosymmetric materials, such as starch granules, and therefore can be used for label-free imaging. Both intensity and polarization of SHG are determined by material properties that are characterized by the nonlinear susceptibility tensor, ((2)). Examination of the tensor is performed for each focal volume of the image by measuring the outgoing polarization state of the SHG signal for a set of incoming laser beam polarizations. Mapping of nonlinear properties expressed as the susceptibility ratio reveals structural features including the organization of crystalline material within a single starch granule, and the distribution of structural properties in a population of granules. Isolated granules, as well as in situ starch, can be analyzed using polarimetric SHG microscopy. Due to the fast sample preparation and short imaging times, polarimetric SHG microscopy allows for a quick assessment of starch structure and permits rapid feedback for bioengineering applications. This article presents the basics of SHG theory and microscopy applications for starch-containing materials. Quantification of ultrastructural features within individual starch granules is described. New results obtained by polarization resolved SHG microscopy of starch granules are presented for various maize genotypes revealing heterogeneity within a single starch particle and between various granules.}, language = {en} } @article{CisekTokarzKrouglovetal.2014, author = {Cisek, Richard and Tokarz, Danielle and Krouglov, Serguei and Steup, Martin and Emes, Michael J. and Tetlow, Ian J. and Barzda, Virginijus}, title = {Second harmonic generation mediated by aligned water in starch granules}, series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry}, volume = {118}, journal = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry}, number = {51}, publisher = {American Chemical Society}, address = {Washington}, issn = {1520-6106}, doi = {10.1021/jp508751s}, pages = {14785 -- 14794}, year = {2014}, abstract = {The origin of second harmonic generation (SHG) in starch granules was investigated using ab initio quantum mechanical modeling and experimentally examined using polarization-in, polarization-out (PIPO) second harmonic generation microscopy. Ab initio calculations revealed that the largest contribution to the SHG signal from A- and B-type allomorphs of starch originates from the anisotropic organization of hydroxide and hydrogen bonds mediated by aligned water found in the polymers. The hypothesis was experimentally tested by imaging maize starch granules under various hydration and heat treatment conditions that alter the hydrogen bond network. The highest SHG intensity was found in fully hydrated starch granules, and heat treatment diminished the SHG intensity. The PIPO SHG imaging showed that dried starch granules have a much higher nonlinear optical susceptibility component ratio than fully hydrated granules. In contrast, deuterated starch granules showed a smaller susceptibility component ratio demonstrating that SHG is highly sensitive to the organization of the hydroxyl and hydrogen bond network. The polarization SHG imaging results of potato starch granules, representing starch allomorph B, were compared to those of maize starch granules representing allomorph A. The results showed that the amount of aligned water was higher in the maize granules. Nonlinear microscopy of starch granules provides evidence that varying hydration conditions leads to significant changes in the nonlinear susceptibility ratio as well as the SHG intensity, supporting the hypothesis from ab initio calculations that the dominant contribution to SHG is due to the ordered hydroxide and hydrogen bond network.}, language = {en} } @article{CisekTokarzSteupetal.2015, author = {Cisek, Richard and Tokarz, Danielle and Steup, Martin and Tetlow, Ian J. and Emes, Michael J. and Hebelstrup, Kim H. and Blennow, Andreas and Barzda, Virginijus}, title = {Second harmonic generation microscopy investigation of the crystalline ultrastructure of three barley starch lines affected by hydration}, series = {Biomedical optics express}, volume = {6}, journal = {Biomedical optics express}, number = {10}, publisher = {Optical Society of America}, address = {Washington}, issn = {2156-7085}, doi = {10.1364/BOE.6.003694}, pages = {3694 -- 3700}, year = {2015}, abstract = {Second harmonic generation (SHG) microscopy is employed to study changes in crystalline organization due to altered gene expression and hydration in barley starch granules. SHG intensity and susceptibility ratio values (R'(SHG)) are obtained using reduced Stokes-Mueller polarimetric microscopy. The maximum R'(SHG) values occur at moderate moisture indicating the narrowest orientation distribution of nonlinear dipoles from the cylindrical axis of glucan helices. The maximum SHG intensity occurs at the highest moisture and amylopectin content. These results support the hypothesis that SHG is caused by ordered hydrogen and hydroxyl bond networks which increase with hydration of starch granules. (C) 2015 Optical Society of America}, language = {en} } @article{ComparotMossKoettingStettleretal.2010, author = {Comparot-Moss, Sylviane and Koetting, Oliver and Stettler, Michaela and Edner, Christoph and Graf, Alexander and Weise, Sean E. and Streb, Sebastian and Lue, Wei-Ling and MacLean, Daniel and Mahlow, Sebastian and Ritte, Gerhard and Steup, Martin and Chen, Jychian and Zeeman, Samuel C. and Smith, Alison M.}, title = {A putative phosphatase, LSF1, is required for normal starch turnover in Arabidopsis leaves}, issn = {0032-0889}, doi = {10.1104/pp.109.148981}, year = {2010}, abstract = {A putative phosphatase, LSF1 (for LIKE SEX4; previously PTPKIS2), is closely related in sequence and structure to STARCH-EXCESS4 (SEX4), an enzyme necessary for the removal of phosphate groups from starch polymers during starch degradation in Arabidopsis (Arabidopsis thaliana) leaves at night. We show that LSF1 is also required for starch degradation: lsf1 mutants, like sex4 mutants, have substantially more starch in their leaves than wild-type plants throughout the diurnal cycle. LSF1 is chloroplastic and is located on the surface of starch granules. lsf1 and sex4 mutants show similar, extensive changes relative to wild-type plants in the expression of sugar-sensitive genes. However, although LSF1 and SEX4 are probably both involved in the early stages of starch degradation, we show that LSF1 neither catalyzes the same reaction as SEX4 nor mediates a sequential step in the pathway. Evidence includes the contents and metabolism of phosphorylated glucans in the single mutants. The sex4 mutant accumulates soluble phospho- oligosaccharides undetectable in wild-type plants and is deficient in a starch granule-dephosphorylating activity present in wild-type plants. The lsf1 mutant displays neither of these phenotypes. The phenotype of the lsf1/sex4 double mutant also differs from that of both single mutants in several respects. We discuss the possible role of the LSF1 protein in starch degradation.}, language = {en} } @article{DauvilleeChochoisSteupetal.2006, author = {Dauvillee, David and Chochois, Vincent and Steup, Martin and Haebel, Sophie and Eckermann, Nora and Ritte, Gerhard and Ral, Jean-Philippe and Colleoni, Christophe and Hicks, Glenn and Wattebled, Fabrice and Deschamps, Philippe and Lienard, Luc and Cournac, Laurent and Putaux, Jean-Luc and Dupeyre, Danielle and Ball, Steven G.}, title = {Plastidial phosphorylase is required for normal starch synthesis in Chlamydomonas reinhardtii}, series = {The plant journal}, volume = {48}, journal = {The plant journal}, number = {2}, publisher = {Blackwell}, address = {Oxford}, issn = {0960-7412}, doi = {10.1111/j.1365-313X.2006.02870.x}, pages = {274 -- 285}, year = {2006}, abstract = {Among the three distinct starch phosphorylase activities detected in Chlamydomonas reinhardtii, two distinct plastidial enzymes (PhoA and PhoB) are documented while a single extraplastidial form (PhoC) displays a higher affinity for glycogen as in vascular plants. The two plastidial phosphorylases are shown to function as homodimers containing two 91-kDa (PhoA) subunits and two 110-kDa (PhoB) subunits. Both lack the typical 80-amino-acid insertion found in the higher plant plastidial forms. PhoB is exquisitely sensitive to inhibition by ADP-glucose and has a low affinity for malto-oligosaccharides. PhoA is more similar to the higher plant plastidial phosphorylases: it is moderately sensitive to ADP-glucose inhibition and has a high affinity for unbranched malto-oligosaccharides. Molecular analysis establishes that STA4 encodes PhoB. Chlamydomonas reinhardtii strains carrying mutations at the STA4 locus display a significant decrease in amounts of starch during storage that correlates with the accumulation of abnormally shaped granules containing a modified amylopectin structure and a high amylose content. The wild-type phenotype could be rescued by reintroduction of the cloned wild-type genomic DNA, thereby demonstrating the involvement of phosphorylase in storage starch synthesis.}, language = {en} }