TY  - JOUR
A1  - Schmieder, Peter
A1  - Nitschke, Felix
A1  - Steup, Martin
A1  - Mallow, Keven
A1  - Specker, Edgar
T1  - Determination of glucan phosphorylation using heteronuclear H-1,C-13 double and H-1,C-13,P-31 triple-resonance NMR spectra
JF  - Magnetic resonance in chemistry
N2  - Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear H-1,C-13 and H-1,C-13,P-31 techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples.
KW  - heteronuclear NMR
KW  - triple resonance
KW  - phosphorylation
KW  - starch
Y1  - 2013
U6  - https://doi.org/10.1002/mrc.3996
SN  - 0749-1581
VL  - 51
IS  - 10
SP  - 655
EP  - 661
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Nitschke, Felix
A1  - Wang, Peixiang
A1  - Schmieder, Peter
A1  - Girard, Jean-Marie
A1  - Awrey, Donald E.
A1  - Wang, Tony
A1  - Israelian, Johan
A1  - Zhao, XiaoChu
A1  - Turnbull, Julie
A1  - Heydenreich, Matthias
A1  - Kleinpeter, Erich
A1  - Steup, Martin
A1  - Minassian, Berge A.
T1  - Hyperphosphorylation of glucosyl C6 carbons and altered structure of glycogen in the neurodegenerative epilepsy lafora disease
JF  - Cell metabolism
N2  - Laforin or malin deficiency causes Lafora disease, characterized by altered glycogen metabolism and teenage-onset neurodegeneration with intractable and invariably fatal epilepsy. Plant starches possess small amounts of metabolically essential monophosphate esters. Glycogen contains similar phosphate amounts, which are thought to originate from a glycogen synthase error side reaction and therefore lack any specific function. Glycogen is also believed to lack monophosphates at glucosyl carbon C6, an essential phosphorylation site in plant starch metabolism. We now show that glycogen phosphorylation is not due to a glycogen synthase side reaction, that C6 is a major glycogen phosphorylation site, and that C6 monophosphates predominate near centers of glycogen molecules and positively correlate with glycogen chain lengths. Laforin or malin deficiency causes C6 hyperphosphorylation, which results in malformed long-chained glycogen that accumulates in many tissues, causing neurodegeneration in brain. Our work advances the understanding of Lafora disease pathogenesis and suggests that glycogen phosphorylation has important metabolic function.
Y1  - 2013
U6  - https://doi.org/10.1016/j.cmet.2013.04.006
SN  - 1550-4131
SN  - 1932-7420
VL  - 17
IS  - 5
SP  - 756
EP  - 767
PB  - Cell Press
CY  - Cambridge
ER  -