@article{CockburnSiegmannPayneetal.2011,
  author    = {Cockburn, Robert A. and Siegmann, Rebekka and Payne, Kevin A. and Beuermann, Sabine and McKenna, Timothy F. L. and Hutchinson, Robin A.},
  title     = {Free Radical Copolymerization Kinetics of gamma-Methyl-alpha-methylene-gamma-butyrolactone (MeMBL)},
  series = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences},
  volume    = {12},
  journal   = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences},
  number    = {6},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1525-7797},
  doi       = {10.1021/bm200400s},
  pages     = {2319 -- 2326},
  year      = {2011},
  abstract  = {The propagation kinetics and copolymerization behavior of the biorenewable monomer gamma-methyl-alpha-methylene-gamma-butyrolactone (MeMBL) are studied using the Pulsed laser polymerization (PLP)/size exclusion chromatography (SEC) technique. The propagation rate coefficent for MeMBL is 15\% higher than that of its structural analogue, methyl methacrylate (MMA), with a similar activation energy of 21.8 kJ . mol(-1). When compared to MMA, MeMBL is preferentially incorporated into copolymers when reacted with styrene (ST), MMA, and n-butyl acrylate (BA); the monomer reactivity ratios fit from bulk MeMBL/ST, MeMBL/MMA, and MeMBL/BA copolymerizations are r(MeMBL) = 0.80 +/- 0.04 and r(ST) = 0.34 +/- 0.04, r(MeMBL), = 3.0 +/- 0.3 and r(MMA) = 0.33 +/- 0.01, and r(MeMBL) = 7.0 +/- 2.0 and r(BA) = 0.16 +/- 0.03, respectively. In all cases, no significant variation with temperature was found between 50 and 90 degrees C. The implicit penultimate unit effect (IPUE) model was found to adequately fit the composition-averaged copolymerization propagation rate coefficient, k(p,cop), for the three systems.},
  language  = {en}
}
@article{RuzanskiSmirnovaRejzeketal.2013,
  author    = {Ruzanski, Christian and Smirnova, Julia and Rejzek, Martin and Cockburn, Darrell and Pedersen, Henriette L. and Pike, Marilyn and Willats, William G. T. and Svensson, Birte and Steup, Martin and Ebenh{\"o}h, Oliver and Smith, Alison M. and Field, Robert A.},
  title     = {A bacterial glucanotransferase can replace the complex maltose metabolism required for starch to sucrose conversion in leaves at night},
  series = {The journal of biological chemistry},
  volume    = {288},
  journal   = {The journal of biological chemistry},
  number    = {40},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {0021-9258},
  doi       = {10.1074/jbc.M113.497867},
  pages     = {28581 -- 28598},
  year      = {2013},
  abstract  = {Controlled conversion of leaf starch to sucrose at night is essential for the normal growth of Arabidopsis. The conversion involves the cytosolic metabolism of maltose to hexose phosphates via an unusual, multidomain protein with 4-glucanotransferase activity, DPE2, believed to transfer glucosyl moieties to a complex heteroglycan prior to their conversion to hexose phosphate via a cytosolic phosphorylase. The significance of this complex pathway is unclear; conversion of maltose to hexose phosphate in bacteria proceeds via a more typical 4-glucanotransferase that does not require a heteroglycan acceptor. It has recently been suggested that DPE2 generates a heterogeneous series of terminal glucan chains on the heteroglycan that acts as a glucosyl buffer to ensure a constant rate of sucrose synthesis in the leaf at night. Alternatively, DPE2 and/or the heteroglycan may have specific properties important for their function in the plant. To distinguish between these ideas, we compared the properties of DPE2 with those of the Escherichia coli glucanotransferase MalQ. We found that MalQ cannot use the plant heteroglycan as an acceptor for glucosyl transfer. However, experimental and modeling approaches suggested that it can potentially generate a glucosyl buffer between maltose and hexose phosphate because, unlike DPE2, it can generate polydisperse malto-oligosaccharides from maltose. Consistent with this suggestion, MalQ is capable of restoring an essentially wild-type phenotype when expressed in mutant Arabidopsis plants lacking DPE2. In light of these findings, we discuss the possible evolutionary origins of the complex DPE2-heteroglycan pathway.},
  language  = {en}
}