Frederic A Troy II - Academia.edu (original) (raw)
Papers by Frederic A Troy II
Background: Lactoferrin (Lf) is an iron-binding, sialylated glycoprotein prevalent in milk, and k... more Background: Lactoferrin (Lf) is an iron-binding, sialylated glycoprotein prevalent in milk, and known to have multifunctional health benefits. Its potential role in neurodevelopment and cognition r...
Journal of Nutrition & Intermediary Metabolism
Journal of Nutrition & Intermediary Metabolism, 2014
The CMPs-dsac acid:polya2,8sialosyl sdalyltransferase (poIyST) in neurotropc Escherichia coU K1 i... more The CMPs-dsac acid:polya2,8sialosyl sdalyltransferase (poIyST) in neurotropc Escherichia coU K1 inner mmbras catalyzes ythes of the a2,8-llnked polyslalk add capsule. The capse is a neurovirulet determinant associated with neonatal ngtis In han. Afuioy smilar pyST I hu neurol s polysalylates neural cell adhesi l cule. While bacteria do not stheize glycosphingollplds (GSLs), we report here that the E. coil K1 pOlyST can selectively polysalylate several str rally elated GSLs, when added ase s_ salyl actors. A sttural feature common to the preferred slay accepors (Gw > GTl > GQb = GTlib> GD2 = GDlb = GD1a > Gm) was the dislayl glycotope, Siaa2,8SIa, a2,3-linked to e (Sa is sialic acid). Aliear tetrmccharlde with a terminal Sa residue (e.g., GDw) was the minimum length go rlde r id by the polyST. Endo-N-a-cd uwas used to cim the a2,8-specifc polysylatbd of GSL. Ceramide glycaas was used to release the polylyllactose chains from the ceramide moiety. Size analysis of these cha...
The nature of endogenous acceptor molecules implicated in the membrane-directed synthesis of the ... more The nature of endogenous acceptor molecules implicated in the membrane-directed synthesis of the polysialic acid (polysia) capsule in Escherichia coli Kl serotypes is not known. The capsule contains at least 200 sialic acid (Sia) residues that are elongated by the addition of new Sia residues to the nonreducing termini of growing nascent chains (Rohr, T. E., and Troy, F. A. (1980) J. Biol. Chem. 255, 2332-2342). Presumably, chain growth starts when activated Sia residues are transferred to acceptors that are not already sialylated. In the present study, we used an acapsular mutant defective in synthesis of CMP-NeuAc to label acceptors with [14C]NeuAc and an anti-polysia-specific antibody (H.46) to identify the molecules to which the polySia was attached. I’4C]Sia-labeled acceptors were solubilized with 2% Triton X-100, immunoprecipitated with H.46, and partially depolymerized with poly-a-2,8-endo-N-acetylneuraminidase. Approximately 5% of the [14C]Sia incorporated remained attached ...
Journal of Nutrition & Intermediary Metabolism
Journal of Biological Chemistry
Chemistry and Biosynthesis of the Poly(y-wglutamyl) Capsule in Bacillus licheniformis I. PROPERTI... more Chemistry and Biosynthesis of the Poly(y-wglutamyl) Capsule in Bacillus licheniformis I. PROPERTIES OF THE MEMBRANE-MEDIATED BIOSYNTHETIC REACTION"
Molecular Nutrition & Food Research
International Journal of Molecular Sciences
Polysialic acid (polySia) is an unusual glycan that posttranslational modifies neural cell adhesi... more Polysialic acid (polySia) is an unusual glycan that posttranslational modifies neural cell adhesion molecule (NCAM) proteins in mammalian cells. The up-regulated expression of polySia-NCAM is associated with tumor progression in many metastatic human cancers and in neurocognitive processes. Two members of the ST8Sia family of α2,8-polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST) both catalyze synthesis of polySia when activated cytidine monophosphate(CMP)-Sialic acid (CMP-Sia) is translocate into the lumen of the Golgi apparatus. Two key polybasic domains in the polySTs, the polybasic region (PBR) and the polysialyltransferase domain (PSTD) areessential forpolysialylation of the NCAM proteins. However, the precise molecular details to describe the interactions required for polysialylation remain unknown. In this study, we hypothesize that PSTD interacts with both CMP-Sia and polySia to catalyze polysialylation of the NCAM proteins. To test this hypothesis, we sy...
Chembiochem : a European journal of chemical biology, Jul 26, 2017
Polysialic acid plays a key role in cancer metastasis and neurodevelopment. Our aim was to determ... more Polysialic acid plays a key role in cancer metastasis and neurodevelopment. Our aim was to determine the developmental gene-expression profiles for the two polysialyltransferases ST8Sia II and ST8Sia IV, neural cell-adhesion molecules (NCAMs), SynCAM 1, neuropilin-2 (NRP2) and their polysialylated cognate glycans in different regions of the piglet brain during postnatal development. Our findings show that: 1) the cellular levels of mRNA coding for ST8Sia II and ST8Sia IV, NCAMs, SynCAM 1, NRP2 and polySia are age-dependent and cell-type-specific during neonatal brain development, 2) there was a lack of correlation between abundance level of mRNA coding for ST8Sia II and ST8Sia IV and the abundance level of the post-translation expression of polySia in all nine brain regions, 3) expression levels of polySia did not correlate with the levels of the carrier proteins NCAM-140, SynCAM 1 and NRP2 in nine brain regions, and 4) the cellular abundance of ST8Sia II and ST8Sia IV in nine subre...
Glycoconjugate journal, Feb 9, 2016
Recent studies have shown a relationship between the level of the sialic acid (Sia), N-glycolylne... more Recent studies have shown a relationship between the level of the sialic acid (Sia), N-glycolylneuraminic acid (Neu5Gc) in red meat and its risk in cancer, cardiovascular and inflammatory diseases. Unresolved is the Sia concentration in different organs of piglets during development. Our aim was to determine the level of free and conjugated forms of Neu5Gc, N-acetylneuraminic acid (Neu5Ac) and ketodeoxynonulsonic acid (Kdn) in fresh and cooked spleen, kidney, lung, heart, liver, and skeletal muscle from 3-days-old (n = 4-8), 38-days-old (n = 10) and adult piglets (n = 4) by LC-MS/MS. Our findings show: (1) Lung tissue from 3 days-old piglets contained the highest level of total Sia (14.6 μmol/g protein) compared with other organs or age groups; (2) Unexpectedly, Neu5Gc was the major Sia in spleen (67-79 %) and adult lung (36-49 %) while free Kdn was the major Sia in skeletal muscle. Conjugated Neu5Ac was the highest Sia in other organs (61-84 %); (3) Skeletal muscle contained the lo...
Journal of Biological Chemistry, Oct 25, 1984
The polysialosyl capsule in Escherichia coli K1 is not synthesized when cells are grown at 15 "C.... more The polysialosyl capsule in Escherichia coli K1 is not synthesized when cells are grown at 15 "C. Membranous sialyltransferase complexes isolated from cells grown at 15 "C spontaneously gain the ability to synthesize sialyl polymers when incubated at 33 "C for 2-4 h. Activation of the endogenous synthesis of polysialic acid is localized in a low-density vesicle fraction (Whitfield, C., Adams, D. A., and Troy, F. A. (1984) J. Biol. Chem. 259,12769-12775). The low density vesicles catalyzed protein synthesis, and spontaneous activation required protein synthesis. Immune blotting confirmed the presence of protein synthesis initiation factor, IF2, and ribosomal protein S6, in the low-density vesicle fraction. Temperature-upshift experiments identified four membrane proteins whose synthesis was temporally correlated with in vitro activation. These proteins have apparent molecular masses o f 40, 21, 17.5, and 16 kDA. Although the function of these proteins is not known, they may relate to a sialyltransferase activity required to initiate sialyl polymer assembly, to an endogenous acceptor, or to a porin that may facilitate channeling of the polysialosyl chains through the outer membrane.
Cancer Research, Oct 1, 1980
The humoral antibody response of cats infected naturally with feline leukemia virus (FeLV) was me... more The humoral antibody response of cats infected naturally with feline leukemia virus (FeLV) was measured by an enzymelinked immunosorbent assay. Cats that became persistently viremic developed lower antibody levels than did cats which recovered from the infection. Cats that were viremic for 2 to 36 weeks prior to recovery had variable enzyme-linked immuno sorbent assay values that overlapped with the values seen in both nonviremic and persistently viremic cats. There was a strong correlation between antibody levels against FeLV and antibodies to feline oncornavirus-associated cell membrane antigen in sera from cats which recovered from FeLV infection but not in sera from cats that were persistently viremic. Sera from persistently viremic and recovered cats were analyzed by a combination of gel electrophoresis and enzymelinked immunosorbent assay, a procedure which permitted the levels of antibodies to each of the protein components of purified FeLV to be quantitated. Sera from recovered cats contained antibodies reactive against the five major FeLV struc tural proteins (gp73, p27, p15, p12, p10) and against eight additional antigenic components with apparent molecular weight values of 58,
The Faseb Journal, Apr 1, 2014
Methods in Enzymology, 1985
Background: Lactoferrin (Lf) is an iron-binding, sialylated glycoprotein prevalent in milk, and k... more Background: Lactoferrin (Lf) is an iron-binding, sialylated glycoprotein prevalent in milk, and known to have multifunctional health benefits. Its potential role in neurodevelopment and cognition r...
Journal of Nutrition & Intermediary Metabolism
Journal of Nutrition & Intermediary Metabolism, 2014
The CMPs-dsac acid:polya2,8sialosyl sdalyltransferase (poIyST) in neurotropc Escherichia coU K1 i... more The CMPs-dsac acid:polya2,8sialosyl sdalyltransferase (poIyST) in neurotropc Escherichia coU K1 inner mmbras catalyzes ythes of the a2,8-llnked polyslalk add capsule. The capse is a neurovirulet determinant associated with neonatal ngtis In han. Afuioy smilar pyST I hu neurol s polysalylates neural cell adhesi l cule. While bacteria do not stheize glycosphingollplds (GSLs), we report here that the E. coil K1 pOlyST can selectively polysalylate several str rally elated GSLs, when added ase s_ salyl actors. A sttural feature common to the preferred slay accepors (Gw > GTl > GQb = GTlib> GD2 = GDlb = GD1a > Gm) was the dislayl glycotope, Siaa2,8SIa, a2,3-linked to e (Sa is sialic acid). Aliear tetrmccharlde with a terminal Sa residue (e.g., GDw) was the minimum length go rlde r id by the polyST. Endo-N-a-cd uwas used to cim the a2,8-specifc polysylatbd of GSL. Ceramide glycaas was used to release the polylyllactose chains from the ceramide moiety. Size analysis of these cha...
The nature of endogenous acceptor molecules implicated in the membrane-directed synthesis of the ... more The nature of endogenous acceptor molecules implicated in the membrane-directed synthesis of the polysialic acid (polysia) capsule in Escherichia coli Kl serotypes is not known. The capsule contains at least 200 sialic acid (Sia) residues that are elongated by the addition of new Sia residues to the nonreducing termini of growing nascent chains (Rohr, T. E., and Troy, F. A. (1980) J. Biol. Chem. 255, 2332-2342). Presumably, chain growth starts when activated Sia residues are transferred to acceptors that are not already sialylated. In the present study, we used an acapsular mutant defective in synthesis of CMP-NeuAc to label acceptors with [14C]NeuAc and an anti-polysia-specific antibody (H.46) to identify the molecules to which the polySia was attached. I’4C]Sia-labeled acceptors were solubilized with 2% Triton X-100, immunoprecipitated with H.46, and partially depolymerized with poly-a-2,8-endo-N-acetylneuraminidase. Approximately 5% of the [14C]Sia incorporated remained attached ...
Journal of Nutrition & Intermediary Metabolism
Journal of Biological Chemistry
Chemistry and Biosynthesis of the Poly(y-wglutamyl) Capsule in Bacillus licheniformis I. PROPERTI... more Chemistry and Biosynthesis of the Poly(y-wglutamyl) Capsule in Bacillus licheniformis I. PROPERTIES OF THE MEMBRANE-MEDIATED BIOSYNTHETIC REACTION"
Molecular Nutrition & Food Research
International Journal of Molecular Sciences
Polysialic acid (polySia) is an unusual glycan that posttranslational modifies neural cell adhesi... more Polysialic acid (polySia) is an unusual glycan that posttranslational modifies neural cell adhesion molecule (NCAM) proteins in mammalian cells. The up-regulated expression of polySia-NCAM is associated with tumor progression in many metastatic human cancers and in neurocognitive processes. Two members of the ST8Sia family of α2,8-polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST) both catalyze synthesis of polySia when activated cytidine monophosphate(CMP)-Sialic acid (CMP-Sia) is translocate into the lumen of the Golgi apparatus. Two key polybasic domains in the polySTs, the polybasic region (PBR) and the polysialyltransferase domain (PSTD) areessential forpolysialylation of the NCAM proteins. However, the precise molecular details to describe the interactions required for polysialylation remain unknown. In this study, we hypothesize that PSTD interacts with both CMP-Sia and polySia to catalyze polysialylation of the NCAM proteins. To test this hypothesis, we sy...
Chembiochem : a European journal of chemical biology, Jul 26, 2017
Polysialic acid plays a key role in cancer metastasis and neurodevelopment. Our aim was to determ... more Polysialic acid plays a key role in cancer metastasis and neurodevelopment. Our aim was to determine the developmental gene-expression profiles for the two polysialyltransferases ST8Sia II and ST8Sia IV, neural cell-adhesion molecules (NCAMs), SynCAM 1, neuropilin-2 (NRP2) and their polysialylated cognate glycans in different regions of the piglet brain during postnatal development. Our findings show that: 1) the cellular levels of mRNA coding for ST8Sia II and ST8Sia IV, NCAMs, SynCAM 1, NRP2 and polySia are age-dependent and cell-type-specific during neonatal brain development, 2) there was a lack of correlation between abundance level of mRNA coding for ST8Sia II and ST8Sia IV and the abundance level of the post-translation expression of polySia in all nine brain regions, 3) expression levels of polySia did not correlate with the levels of the carrier proteins NCAM-140, SynCAM 1 and NRP2 in nine brain regions, and 4) the cellular abundance of ST8Sia II and ST8Sia IV in nine subre...
Glycoconjugate journal, Feb 9, 2016
Recent studies have shown a relationship between the level of the sialic acid (Sia), N-glycolylne... more Recent studies have shown a relationship between the level of the sialic acid (Sia), N-glycolylneuraminic acid (Neu5Gc) in red meat and its risk in cancer, cardiovascular and inflammatory diseases. Unresolved is the Sia concentration in different organs of piglets during development. Our aim was to determine the level of free and conjugated forms of Neu5Gc, N-acetylneuraminic acid (Neu5Ac) and ketodeoxynonulsonic acid (Kdn) in fresh and cooked spleen, kidney, lung, heart, liver, and skeletal muscle from 3-days-old (n = 4-8), 38-days-old (n = 10) and adult piglets (n = 4) by LC-MS/MS. Our findings show: (1) Lung tissue from 3 days-old piglets contained the highest level of total Sia (14.6 μmol/g protein) compared with other organs or age groups; (2) Unexpectedly, Neu5Gc was the major Sia in spleen (67-79 %) and adult lung (36-49 %) while free Kdn was the major Sia in skeletal muscle. Conjugated Neu5Ac was the highest Sia in other organs (61-84 %); (3) Skeletal muscle contained the lo...
Journal of Biological Chemistry, Oct 25, 1984
The polysialosyl capsule in Escherichia coli K1 is not synthesized when cells are grown at 15 "C.... more The polysialosyl capsule in Escherichia coli K1 is not synthesized when cells are grown at 15 "C. Membranous sialyltransferase complexes isolated from cells grown at 15 "C spontaneously gain the ability to synthesize sialyl polymers when incubated at 33 "C for 2-4 h. Activation of the endogenous synthesis of polysialic acid is localized in a low-density vesicle fraction (Whitfield, C., Adams, D. A., and Troy, F. A. (1984) J. Biol. Chem. 259,12769-12775). The low density vesicles catalyzed protein synthesis, and spontaneous activation required protein synthesis. Immune blotting confirmed the presence of protein synthesis initiation factor, IF2, and ribosomal protein S6, in the low-density vesicle fraction. Temperature-upshift experiments identified four membrane proteins whose synthesis was temporally correlated with in vitro activation. These proteins have apparent molecular masses o f 40, 21, 17.5, and 16 kDA. Although the function of these proteins is not known, they may relate to a sialyltransferase activity required to initiate sialyl polymer assembly, to an endogenous acceptor, or to a porin that may facilitate channeling of the polysialosyl chains through the outer membrane.
Cancer Research, Oct 1, 1980
The humoral antibody response of cats infected naturally with feline leukemia virus (FeLV) was me... more The humoral antibody response of cats infected naturally with feline leukemia virus (FeLV) was measured by an enzymelinked immunosorbent assay. Cats that became persistently viremic developed lower antibody levels than did cats which recovered from the infection. Cats that were viremic for 2 to 36 weeks prior to recovery had variable enzyme-linked immuno sorbent assay values that overlapped with the values seen in both nonviremic and persistently viremic cats. There was a strong correlation between antibody levels against FeLV and antibodies to feline oncornavirus-associated cell membrane antigen in sera from cats which recovered from FeLV infection but not in sera from cats that were persistently viremic. Sera from persistently viremic and recovered cats were analyzed by a combination of gel electrophoresis and enzymelinked immunosorbent assay, a procedure which permitted the levels of antibodies to each of the protein components of purified FeLV to be quantitated. Sera from recovered cats contained antibodies reactive against the five major FeLV struc tural proteins (gp73, p27, p15, p12, p10) and against eight additional antigenic components with apparent molecular weight values of 58,
The Faseb Journal, Apr 1, 2014
Methods in Enzymology, 1985