DARREL STAFFORD

Summary

Affiliation: University of North Carolina
Country: USA

Publications

  1. ncbi request reprint The vitamin K cycle
    D W Stafford
    Department of Biology and Pathology, University of North Carolina, Chapel Hill, NC 27599 3280, USA
    J Thromb Haemost 3:1873-8. 2005
  2. ncbi request reprint The putative vitamin K-dependent gamma-glutamyl carboxylase internal propeptide appears to be the propeptide binding site
    Pen Jen Lin
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 3280, USA
    J Biol Chem 277:28584-91. 2002
  3. pmc Correction of factor IX deficiency in mice by embryonic stem cells differentiated in vitro
    Jeffrey H Fair
    Department of Surgery, University of North Carolina, Chapel Hill, NC 27599, USA
    Proc Natl Acad Sci U S A 102:2958-63. 2005
  4. ncbi request reprint Determination of disulfide bond assignment of human vitamin K-dependent gamma-glutamyl carboxylase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
    Jian Ke Tie
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 278:45468-75. 2003
  5. pmc Transmembrane domain interactions and residue proline 378 are essential for proper structure, especially disulfide bond formation, in the human vitamin K-dependent gamma-glutamyl carboxylase
    Jian Ke Tie
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    Biochemistry 47:6301-10. 2008
  6. ncbi request reprint Identification of the N-linked glycosylation sites of vitamin K-dependent carboxylase and effect of glycosylation on carboxylase function
    Jian Ke Tie
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    Biochemistry 45:14755-63. 2006
  7. ncbi request reprint Chemical modification of cysteine residues is a misleading indicator of their status as active site residues in the vitamin K-dependent gamma-glutamyl carboxylation reaction
    Jian Ke Tie
    Departments of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 279:54079-87. 2004
  8. ncbi request reprint Binding of the factor IX gamma-carboxyglutamic acid domain to the vitamin K-dependent gamma-glutamyl carboxylase active site induces an allosteric effect that may ensure processive carboxylation and regulate the release of carboxylated product
    Pen Jen Lin
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 279:6560-6. 2004
  9. ncbi request reprint The conversion of vitamin K epoxide to vitamin K quinone and vitamin K quinone to vitamin K hydroquinone uses the same active site cysteines
    Da Yun Jin
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 3280, USA
    Biochemistry 46:7279-83. 2007
  10. ncbi request reprint Vitamin K epoxide reductase significantly improves carboxylation in a cell line overexpressing factor X
    Yan Mei Sun
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 3280, USA
    Blood 106:3811-5. 2005

Research Grants

  1. Structure/Function of the Gamma-Glutamyl Carboxylase
    DARREL STAFFORD; Fiscal Year: 2005
  2. Structure & Function of the Gamma-Glutamyl Carboxylase
    DARREL STAFFORD; Fiscal Year: 2009
  3. Characterization of Vitamin K Epoxide Reductase
    DARREL STAFFORD; Fiscal Year: 2009
  4. Structure & Function of the Gamma-Glutamyl Carboxylase
    Darrel W Stafford; Fiscal Year: 2010
  5. Characterization of Vitamin K Epoxide Reductase
    Darrel W Stafford; Fiscal Year: 2010
  6. STRUCTURE AND FUNCTION OF GAMMA-GLUTAMYL CARBOXYLASE
    DARREL STAFFORD; Fiscal Year: 1993
  7. STRUCTURE/FUNCTION OF THE GAMMA GLUTAMYL CARBOXYLASE
    DARREL STAFFORD; Fiscal Year: 2000
  8. FACTOR IX MOUSE MODELS FOR HEMOPHILIA B GENE THERAPY
    DARREL STAFFORD; Fiscal Year: 2001
  9. Structure & Function of the Gamma-Glutamyl Carboxylase
    Darrel W Stafford; Fiscal Year: 2011

Collaborators

Detail Information

Publications25

  1. ncbi request reprint The vitamin K cycle
    D W Stafford
    Department of Biology and Pathology, University of North Carolina, Chapel Hill, NC 27599 3280, USA
    J Thromb Haemost 3:1873-8. 2005
    ..It appears, however, that most of the variability observed in patients response to warfarin may be attributed to variability in the VKOR gene...
  2. ncbi request reprint The putative vitamin K-dependent gamma-glutamyl carboxylase internal propeptide appears to be the propeptide binding site
    Pen Jen Lin
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 3280, USA
    J Biol Chem 277:28584-91. 2002
    ..These results agree with our previous observations, indicating that residues in this region are involved in propeptide binding...
  3. pmc Correction of factor IX deficiency in mice by embryonic stem cells differentiated in vitro
    Jeffrey H Fair
    Department of Surgery, University of North Carolina, Chapel Hill, NC 27599, USA
    Proc Natl Acad Sci U S A 102:2958-63. 2005
    ..The PEP engraftment was not associated with detectable cell fusion, and the transplantation was accompanied with only a low incidence of teratoma formation...
  4. ncbi request reprint Determination of disulfide bond assignment of human vitamin K-dependent gamma-glutamyl carboxylase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
    Jian Ke Tie
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 278:45468-75. 2003
    ..Our results indicate that Cys-99 and Cys-450 form the only disulfide bond in carboxylase...
  5. pmc Transmembrane domain interactions and residue proline 378 are essential for proper structure, especially disulfide bond formation, in the human vitamin K-dependent gamma-glutamyl carboxylase
    Jian Ke Tie
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    Biochemistry 47:6301-10. 2008
    ..This latter interaction may be mediated at least in part by a motif of glycine residues in the second transmembrane domain...
  6. ncbi request reprint Identification of the N-linked glycosylation sites of vitamin K-dependent carboxylase and effect of glycosylation on carboxylase function
    Jian Ke Tie
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    Biochemistry 45:14755-63. 2006
    ..Our results suggest that N-linked glycosylation is not essential for carboxylase enzymatic activity but is important for protein folding and stability...
  7. ncbi request reprint Chemical modification of cysteine residues is a misleading indicator of their status as active site residues in the vitamin K-dependent gamma-glutamyl carboxylation reaction
    Jian Ke Tie
    Departments of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 279:54079-87. 2004
    ..We conclude that cysteine residues are not directly involved in carboxylase catalysis, but chemical modification of Cys(323) and Cys(343) may disrupt the three-dimensional structure, resulting in inactivation...
  8. ncbi request reprint Binding of the factor IX gamma-carboxyglutamic acid domain to the vitamin K-dependent gamma-glutamyl carboxylase active site induces an allosteric effect that may ensure processive carboxylation and regulate the release of carboxylated product
    Pen Jen Lin
    Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 279:6560-6. 2004
    ..5) The increased dissociation rate after carboxylation contributes to the release of product...
  9. ncbi request reprint The conversion of vitamin K epoxide to vitamin K quinone and vitamin K quinone to vitamin K hydroquinone uses the same active site cysteines
    Da Yun Jin
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 3280, USA
    Biochemistry 46:7279-83. 2007
    ..H., Huang, T.-Y., Williams, J., and Stafford, D. W. (2006) Proc. Natl. Acad. Sci. U S A. 103, 19308-19313]...
  10. ncbi request reprint Vitamin K epoxide reductase significantly improves carboxylation in a cell line overexpressing factor X
    Yan Mei Sun
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 3280, USA
    Blood 106:3811-5. 2005
    ..In addition to its mechanistic relevance, this observation has practical implications for overproducing recombinant vitamin K-dependent proteins for therapeutic use...
  11. ncbi request reprint A conserved region of human vitamin K-dependent carboxylase between residues 393 and 404 is important for its interaction with the glutamate substrate
    Vasantha P Mutucumarana
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 3280, USA
    J Biol Chem 278:46488-93. 2003
    ..Although propeptide and vitamin K binding in some mutants were affected, our data provide compelling evidence that glutamate recognition is the primary function of the conserved region around Leu394...
  12. pmc Effect of vitamin K-dependent protein precursor propeptide, vitamin K hydroquinone, and glutamate substrate binding on the structure and function of {gamma}-glutamyl carboxylase
    Shannon L Higgins-Gruber
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 285:31502-8. 2010
    ..The two together had a greater effect than either alone. We conclude that the effect of propeptide and substrates on carboxylase controls the order of substrate binding in such a way as to ensure efficient, specific carboxylation...
  13. ncbi request reprint Quantum chemical study of the mechanism of action of vitamin K carboxylase (VKC). IV. Intermediates and transition states
    Charles H Davis
    Department of Biochemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
    J Phys Chem A 111:7257-61. 2007
    ..We relate these computations to the entire vitamin K cycle in the blood coagulation cascade, which is essential for viability of vertebrates...
  14. ncbi request reprint Membrane topology mapping of vitamin K epoxide reductase by in vitro translation/cotranslocation
    Jian Ke Tie
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    J Biol Chem 280:16410-6. 2005
    ..Altogether, our results suggest that VKOR is a type III membrane protein with three transmembrane domains, which agrees well with the prediction by the topology prediction program TMHMM...
  15. ncbi request reprint Creation of a mouse expressing defective human factor IX
    Da Yun Jin
    Gene Therapy Center, Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
    Blood 104:1733-9. 2004
    ..In contrast, given the same treatment, FIXKO mice consistently develop antibodies. Our R333Q-hFIX mice strain will complement the FIXKO mice for studying factor IX circulating kinetics and gene therapy...
  16. pmc Conformational analysis of membrane proteins in phospholipid bilayer nanodiscs by hydrogen exchange mass spectrometry
    Christine M Hebling
    Department of Chemistry, Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    Anal Chem 82:5415-9. 2010
    ....
  17. ncbi request reprint In vivo response to vascular injury in the absence of factor IX: examination in factor IX knockout mice
    Tong Gui
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
    Thromb Res 121:225-34. 2007
    ..In vivo modeling is possible because of the generation of factor IX(-/-) mice...
  18. doi request reprint Structure and function of vitamin K epoxide reductase
    Jian Ke Tie
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 3280, USA
    Vitam Horm 78:103-30. 2008
    ..A detailed mechanism has been published and the purified enzyme should allow the testing of this mechanism. A major unanswered question is the physiological reductant of VKOR...
  19. ncbi request reprint A quantum chemical study of the mechanism of action of Vitamin K epoxide reductase (VKOR) II. Transition states
    Charles H Davis
    Department of Biochemistry and Biophysics, UNC CH, Chapel Hill, NC 27599, United States
    J Mol Graph Model 26:401-8. 2007
    ..These results will be useful for designing more complete QM/MM studies of the enzymatic pathway once three-dimensional structural data is determined and available for VKOR...
  20. ncbi request reprint A quantum chemical study of the mechanism of action of Vitamin K carboxylase (VKC) III. Intermediates and transition states
    Charles H Davis
    Department of Biochemistry and Biophysics, UNC CH, Chapel Hill, 27599, United States
    J Mol Graph Model 26:409-14. 2007
    ..The results are consistent with the idea that the enzyme probably acts to facilitate the formation of the epoxide by reducing the energy required to deprotonate the hydroquinone form...
  21. ncbi request reprint The vitamin K-dependent carboxylase
    Steven R Presnell
    Department of Biology, University of North Carolina Chapel Hill, 27599 3280, USA
    Thromb Haemost 87:937-46. 2002
  22. ncbi request reprint Two-dimensional crystallization of human vitamin K-dependent gamma-glutamyl carboxylase
    Ingeborg Schmidt-Krey
    Georgia Institute of Technology, School of Biology, 310 Ferst Drive, Atlanta, GA 30332 0230, USA
    J Struct Biol 157:437-42. 2007
    ..7 A, b=76.6 A, gamma=91 degrees. Projection maps calculated from images of negatively stained and electron cryo-microscopy samples reveal the human vitamin K-dependent gamma-glutamyl carboxylase to be a monomer...
  23. ncbi request reprint Circulating and binding characteristics of wild-type factor IX and certain Gla domain mutants in vivo
    Tong Gui
    Department of Biology, University of North Carolina at Chapel Hill, 27599 3280, USA
    Blood 100:153-8. 2002
    ..Our results suggest that factor IX Gla-domain mediated binding to endothelial cells/collagen IV plays a role in controlling factor IX concentration in the blood...
  24. ncbi request reprint Identification of the gene for vitamin K epoxide reductase
    Tao Li
    Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    Nature 427:541-4. 2004
    ..The expressed enzyme is 163 amino acids long, with at least one transmembrane domain. Identification of the VKOR gene extends our understanding of blood clotting, and should facilitate development of new anticoagulant drugs...
  25. ncbi request reprint Factor IX variants improve gene therapy efficacy for hemophilia B
    Joerg Schuettrumpf
    The Children s Hospital of Philadelphia, 34th St and Civic Center Blvd, Philadelphia, PA 19104, USA
    Blood 105:2316-23. 2005
    ..IX variants did not trigger antibody formation to F.IX in mice tolerant to F.IX-WT. These studies demonstrate that F.IX variants provide a promising strategy to improve the efficacy for a variety of gene-based therapies for hemophilia B...

Research Grants27

  1. Structure/Function of the Gamma-Glutamyl Carboxylase
    DARREL STAFFORD; Fiscal Year: 2005
    ....
  2. Structure & Function of the Gamma-Glutamyl Carboxylase
    DARREL STAFFORD; Fiscal Year: 2009
    ....
  3. Characterization of Vitamin K Epoxide Reductase
    DARREL STAFFORD; Fiscal Year: 2009
    ..This study of VKOR should lead to a better understanding of the mechanism of warfarin inhibition. It may also result in more accurate dosing of warfarin and in the design of new anti-coagulants. ..
  4. Structure & Function of the Gamma-Glutamyl Carboxylase
    Darrel W Stafford; Fiscal Year: 2010
    ....
  5. Characterization of Vitamin K Epoxide Reductase
    Darrel W Stafford; Fiscal Year: 2010
    ..Another developing area relevant to public health is the role of coagulation/thrombosis in cancer, and in turn whether vitamin K and its antagonists have a place in cancer treatment. ..
  6. STRUCTURE AND FUNCTION OF GAMMA-GLUTAMYL CARBOXYLASE
    DARREL STAFFORD; Fiscal Year: 1993
    ..Make mutations suggested by the above experiments. 5. Examine some aspects of the mechanism of the carboxylation reaction...
  7. STRUCTURE/FUNCTION OF THE GAMMA GLUTAMYL CARBOXYLASE
    DARREL STAFFORD; Fiscal Year: 2000
    ..These studies have significant clinical relevance in that they could lead to improved therapies for blood coagulation and thrombosis disorders. ..
  8. FACTOR IX MOUSE MODELS FOR HEMOPHILIA B GENE THERAPY
    DARREL STAFFORD; Fiscal Year: 2001
    ..The long-term objective is to better understand the molecular role of FIX in vivo with the hope of enhancing effective gene therapy in humans. ..
  9. Structure & Function of the Gamma-Glutamyl Carboxylase
    Darrel W Stafford; Fiscal Year: 2011
    ....