Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Brucella abortus cyclic glucan synthase (Cgs) is a 316-kDa (2,831-amino-acid) integral inner membrane protein that is responsible for the synthesis of cyclic beta-1,2-glucan by a novel mechanism in which the enzyme itself acts as a protein intermediate. B. abortus Cgs uses UDP-glucose as a sugar donor and has the three enzymatic activities necessary for synthesis of the cyclic polysaccharide (i.e., initiation, elongation, and cyclization). Cyclic glucan is required in B. abortus for effective host interaction and complete expression of virulence. To gain further insight into the structure and mechanism of action of B. abortus Cgs, we studied the membrane topology of the protein using a combination of in silico predictions, a genetic approach involving the construction of fusions between the cgs gene and the genes encoding alkaline phosphatase (phoA) and beta-galactosidase (lacZ), and site-directed chemical labeling of lysine residues. We found that B. abortus Cgs is a polytopic membrane protein with the amino and carboxyl termini located in the cytoplasm and with six transmembrane segments, transmembrane segments I (residues 419 to 441), II (residues 452 to 474), III (residues 819 to 841), IV (residues 847 to 869), V (residues 939 to 961), and VI (residues 968 to 990). The six transmembrane segments determine four large cytoplasmic domains and three very small periplasmic regions.
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PMID:Membrane topology analysis of cyclic glucan synthase, a virulence determinant of Brucella abortus. 1548 31

Pollen grains from Phoenix sylvestris (date palm), a commonly cultivated tree in India has been found to cause severe allergic diseases in an increasing percentage of hypersensitive individuals. To unearth its allergenic components, pollen protein were profiled by two-dimensional gel electrophoresis followed by immunoblotting with date palm pollen sensitive patient sera. Allergens were identified by MALDI-TOF/TOF employing a layered proteomic approach combining conventional database dependent search and manual de novo sequencing followed by homology-based search as Phoenix sylvestris is unsequenced. Derivatization of tryptic peptides by acetylation has been demonstrated to differentiate the 'b' from the 'y' ions facilitating efficient de novo sequencing. Ten allergenic proteins were identified, out of which six showed homology with known allergens while others were reported for the first time. Amongst these, isoflavone reductase, beta-conglycinin, S-adenosyl methionine synthase, 1, 4 glucan synthase and beta-galactosidase were commonly reported as allergens from coconut pollen and presumably responsible for cross-reactivity. One of the allergens had IgE binding epitope recognized by its glycan moiety. The allergenic potency of date palm pollen has been demonstrated using in vitro tests. The identified allergens can be used to develop vaccines for immunotherapy against date palm pollen allergy.
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PMID:Charting novel allergens from date palm pollen (Phoenix sylvestris) using homology driven proteomics. 2853 32