Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
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Gene/Protein
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Drug
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Target Concepts:
Gene/Protein
Disease
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Query: EC:2.4.99.7 (
sialyltransferase
)
1,534
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Optimal
assay conditions were determined for four glycosyltransferases in rat small intestinal mucosal homogenates and the regional distribution and cellular localization of these enzymes was studied. For each glycosyltransferase, similar levels of activity were found in duodenal, proximal jejunal and distal ileal segments; activities of the galactosyltransferases were lower in the distal jejunal-proximal ileal segment. Planar section studies indicated that the undifferentiated crypt cells had significantly higher levels of
sialyltransferase
activities in the jejunum and ileum than the mature villus cells. A similar crypt to villus gradient was found for a galactosyltransferase in the ileum. These data suggest that glycoprotein synthesis may be active in the undifferentiated crypt cells and that certain glycosyltransferases may serve as marker enzymes for cellular differentiation in the intestine.
...
PMID:Regional and cellular localization of glycosyltransferases in rat small intestine. Changes in enzymes with differentiation of intestinal epithelial cells. 4 96
Characterization of proteins using NMR methods begins with assignment of resonances to specific residues. This is usually accomplished using sequential connectivities between nuclear pairs in proteins uniformly labeled with NMR active isotopes. This becomes impractical for larger proteins, and especially for proteins that are best expressed in mammalian cells, including glycoproteins. Here an alternate protocol for the assignment of NMR resonances of sparsely labeled proteins, namely, the ones labeled with a single amino acid type, or a limited subset of types, isotopically enriched with
15
N or
13
C, is described. The protocol is based on comparison of data collected using extensions of simple two-dimensional NMR experiments (correlated chemical shifts, nuclear Overhauser effects, residual dipolar couplings) to predictions from molecular dynamics trajectories that begin with known protein structures.
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pairing of predicted and experimental values is facilitated by a software package that employs a genetic algorithm, ASSIGN_SLP_MD. The approach is applied to the 36-kDa luminal domain of the
sialyltransferase
, rST6Gal1, in which all phenylalanines are labeled with
15
N, and the results are validated by elimination of resonances via single-point mutations of selected phenylalanines to tyrosines. Assignment allows the use of previously published paramagnetic relaxation enhancements to evaluate placement of a substrate analog in the active site of this protein. The protocol will open the way to structural characterization of the many glycosylated and other proteins that are best expressed in mammalian cells.
...
PMID:NMR Resonance Assignment Methodology: Characterizing Large Sparsely Labeled Glycoproteins. 3103 88
