Guang-Yi Xu
Yeshiva University
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Publication
Featured researches published by Guang-Yi Xu.
Journal of Biological Chemistry | 1999
Saurabh Menon; Mark Stahl; Ravindra Kumar; Guang-Yi Xu; Francis X. Sullivan
Recently the genes encoding the human andEscherichia coli GDP-mannose dehydratase and GDP-fucose synthetase (GFS) protein have been cloned and it has been shown that these two proteins alone are sufficient to convert GDP mannose to GDP fucose in vitro. GDP-fucose synthetase from E. coli is a novel dual function enzyme in that it catalyzes epimerizations and a reduction reaction at the same active site. This aspect separates fucose biosynthesis from that of other deoxy and dideoxy sugars in which the epimerase and reductase activities are present on separate enzymes encoded by separate genes. By NMR spectroscopy we have shown that GFS catalyzes the stereospecific hydride transfer of the ProS hydrogen from NADPH to carbon 4 of the mannose sugar. This is consistent with the stereospecificity observed for other members of the short chain dehydrogenase reductase family of enzymes of which GFS is a member. Additionally the enzyme is able to catalyze the epimerization reaction in the absence of NADP or NADPH. The kinetic mechanism of GFS as determined by product inhibition and fluorescence binding studies is consistent with a random mechanism. The dissociation constants determined from fluorescence studies indicate that the enzyme displays a 40-fold stronger affinity for the substrate NADPH as compared with the product NADP and utilizes NADPH preferentially as compared with NADH. This study on GFS, a unique member of the short chain dehydrogenase reductase family, coupled with that of its recently published crystal structure should aid in the development of antimicrobial or anti-inflammatory compounds that act by blocking selectin-mediated cell adhesion.
Journal of Biomolecular NMR | 1996
Guang-Yi Xu; Jin Hong; Tom McDonagh; Mark Stahl; Lewis E. Kay; Jasbir Seehra; Dale A. Cumming
SummaryEssentially complete backbone and side-chain 1H, 15N and 13C resonance assignments for the 185-aminoacid cytokine interleukin-6 (IL-6) are presented. NMR experiments were performed on uniformly [15N]-and [15N, 13C]-labeled recombinant human IL-6 (rIL-6) using a variety of heteronuclear NMR experiments. A combination of 13C-chemical shift, amide hydrogen-bond exchange, and 15N-edited NOESY data allowed for analysis of the secondary structure of IL-6. The observed secondary structure of IL-6 is composed of loop regions connecting five α-helices, four of which are consistent in their length and disposition with the four-helix bundle motif present in other related cytokines and previously postulated for IL-6. In addition, the topology of the overall fold was found to be consistent with a left-handed up-up-down-down four-helix bundle based on a number of long-range interhelical NOEs. The results presented here provide deeper insight into structure-function relationships among members of the four-helix bundle family of proteins.
Journal of Biological Chemistry | 1998
Francis X. Sullivan; Ravindra Kumar; Ronald Kriz; Mark Stahl; Guang-Yi Xu; Jason Rouse; Xiao-Jia Chang; Amechand Boodhoo; Barry Potvin; Dale A. Cumming
Journal of Molecular Biology | 1998
Guang-Yi Xu; Thomas McDonagh; Hsiang-Ai Yu; Eric A. Nalefski; James D. Clark; Dale A. Cumming
Journal of Molecular Biology | 1997
Guang-Yi Xu; Hsiang-Ai Yu; Jin Hong; Mark Stahl; Thomas McDonagh; Lewis E. Kay; Dale A. Cumming
Molecular Cell | 2000
Désirée H. H. Tsao; Thomas McDonagh; Jean-Baptiste Telliez; Sang Hsu; Karl Malakian; Guang-Yi Xu; Lih-Ling Lin
Archive | 2000
William Stuart Somers; Mark L. Stahl; Jasbir Seehra; Guang-Yi Xu; Thomas McDonagh; Hsiang-Ai Yu; Jin Hong
Archive | 2004
Desiree Tsao; Jean-Baptiste Telliez; Thomas McDonagh; Lih-Ling Lin; Sang Hsu; Guang-Yi Xu; A. Malakian
Archive | 2003
Steven F. Sukits; Jean-Baptiste Telliez; Lih-Ling Lin; Guang-Yi Xu
Archive | 2003
Kevin D. Parris; William Stuart Somers; Amy Tam; Laura Lin; Mark L. Stahl; Robert Powers; Guang-Yi Xu