Search results for "Glycosyl"

AtPGAP1 functions as a GPI inositol-deacylase required for efficient transport of GPI-anchored proteins

2021

Abstract Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) play an important role in a variety of plant biological processes including growth, stress response, morphogenesis, signaling, and cell wall biosynthesis. The GPI anchor contains a lipid-linked glycan backbone that is synthesized in the endoplasmic reticulum (ER) where it is subsequently transferred to the C-terminus of proteins containing a GPI signal peptide by a GPI transamidase. Once the GPI anchor is attached to the protein, the glycan and lipid moieties are remodeled. In mammals and yeast, this remodeling is required for GPI-APs to be included in Coat Protein II-coated vesicles for their ER export and subsequent t…

The nucleotide and deduced amino acid structures of sheep and pig fetuin. Common structural features of the mammalian fetuin family

1992

This study was initiated to gain further insight into the structural features of the mammalian fetuin family. The cDNA structures of sheep and pig fetuin were determined. The cDNA insert encoding sheep (pig) fetuin comprised 1550 (1470) nucleotides, including 54 (46) nucleotides encoding a signal peptide of 18 (15) residues and 1038 (1041) nucleotides encoding the 346 (347) amino acids of the mature plasma protein. The predicted amino-terminal sequence of the mature pig fetuin was confirmed by the amino-terminal sequence of the purified protein. However, two alternative sheep amino-terminal sequences were found in fetuin purified from the plasma of a single sheep fetus; the minor product wa…

Characterization of a glycosylphosphatidylinositol-bound cell-wall protein (GPI-CWP) in Yarrowia lipolytica.

2004

The structure and composition of the cell wall of yeast has so far been studied mainly in Saccharomyces cerevisiae. It is basically made up of three components: beta-glucans, chitin and mannose-containing glycoproteins, also called mannoproteins. Most covalently bound cell-wall mannoproteins belong to the so-called glycosylphosphatidylinositol cell-wall protein (GPI-CWP) family, cell-wall proteins that are bound through the remnant of a GPI residue to 1,6-beta-glucan. The non-conventional yeast Yarrowia lipolytica shares Generally Regarded As Safe (GRAS) status with S. cerevisiae, has some industrial applications and is increasingly being proposed as a host for the production of recombinant…

Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli

2004

Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin–agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7 free biotin-binding sites per tetramer and showed the same biotin-binding affinity and thermal stability as egg-white avidin. Avidin crystallized under various conditions, which will enable X-ray cryst…

Chemoenzymatic Synthesis of Functional Sialyl LewisX Mimetics with a Heteroaromatic Core

2014

Functional mimetics of the sialyl Lewis(X) tetrasaccharide were prepared by the enzymatic sialylation of a 1,3-diglycosylated indole and a glycosyl azide, which was subsequently transformed into a 1,4-diglycosylated 1,2,3-triazole, by using the trans-sialidase of Trypanosoma cruzi. These compounds inhibited the binding of E-, L-, and P-selectin-coated nanoparticles to polyacrylamide-bound sialyl-Lewis(X) -containing neighboring sulfated tyrosine residues (sTyr/sLe(X) -PAA) at low or sub-millimolar concentrations. Except for E-selectin, the mimetics showed higher activities than the natural tetrasaccharide.

Influence of agents that act on DNA and RNA synthesis on the activity of poly(ADP-Rib) polymerase

1975

The activity of poly(ADP-Rib) polymerase is enhanced in the presence of spermine and spermidine. Among the adenosine-like antibiotics tested, only formycin B and showdomycin cause an inhibition of the enzyme, which is competitive to NAD. The activity of poly(ADP-Rib) polymerase is not reduced by rifamycin, alpha-amanitin and 2-phenylethanol.

Recombinant NeutraLite Avidin: a non-glycosylated, acidic mutant of chicken avidin that exhibits high affinity for biotin and low non-specific bindin…

2000

AbstractA recombinant non-glycosylated and acidic form of avidin was designed and expressed in soluble form in baculovirus-infected insect cells. The mutations were based on the same principles that guided the design of the chemically and enzymatically modified avidin derivative, known as NeutraLite Avidin. In this novel recombinant avidin derivative, five out of the eight arginine residues were replaced with neutral amino acids, and two of the lysine residues were replaced by glutamic acid. In addition, the carbohydrate-bearing asparagine-17 residue was altered to an isoleucine, according to the known sequences of avidin-related genes. The resultant mutant protein, termed recombinant Neutr…

Characterization of poultry egg-white avidins and their potential as a tool in pretargeting cancer treatment.

2003

Chicken avidin and bacterial streptavidin are proteins used in a wide variety of applications in the life sciences due to their strong affinity for biotin. A new and promising use for them is in medical pretargeting cancer treatments. However, their pharmacokinetics and immunological properties are not always optimal, thereby limiting their use in these applications. To search for potentially beneficial new candidates, we screened egg white from four different poultry species for avidin. Avidin proteins, isolated from the duck, goose, ostrich and turkey, showed a similar tetrameric structure, similar glycosylation and stability against both temperature and proteolytic activity of proteinase…

Total Synthesis of the Glycopeptide Recognition Domain of the P-Selectin Glycoprotein Ligand 1

2008

Glucosylation of Rho proteins by Clostridium difficile toxin B.

1995

TOXIN A and B, the major virulence factors of Clostridium difficile, are the causative agents of antibiotic-associated pseudomembran-ous colitis. In cultured cell lines their potent cytotoxicity results from their ability to induce disaggregation of the microfilament cytoskeleton1,2. Toxin B acts on the low-molecular-mass GTPase Rho A3,4, which is involved in the regulation of the actin cytoskeleton. We report here that toxin B catalyses the incorporation of up to one mole of glucose per mole of RhoA at the amino acid thre-onine at position 37. The modification was identified and localized by tandem electrospray mass spectrometry. UDP-glucose selectively serves as cosubstrate for the monogl…