| Autor: |
Laing, J G, Robertson, M W, Gritzmacher, C A, Wang, J L, Liu, F T |
| Zdroj: |
Journal of Biological Chemistry; February 1989, Vol. 264 Issue: 4 p1907-1910, 4p |
| Abstrakt: |
The predicted amino acid sequence of carbohydratebinding protein 35 (CBP35; Mr~35,000), a galactosespecific lectin in many mouse and human cells, has been compared to the predicted sequence of an IgEbinding protein (εBP) originally identified in rat basophilic leukemia cells. The sequences of the two proteins showed that: (a) 85% of the amino acid residues are identical; (b) the polypeptide chains are comprised of two distinct domains; and (c) highly conserved internal repetitive sequences are present. Consistent with these observations, antisera raised against CBP35 or against a synthetic peptide derived from the εBP sequence cross-reacted with both proteins. Moreover, fractionation of extracts of mouse 3T3 fibroblasts over an IgE-Sepharose affinity column showed that CBP35 bound to IgE; this binding was reversed by addition of lactose. Conversely, fractionation of extracts of rat basophilic leukemia cells over an affinity column of Sepharose derivatized with N-(c-amino-CaprOyl)-D-galaCtOSamine showed that εBP was a galactose-binding protein. Furthermore, εBP bound to IgE-Sepharose could bee luted by lactose. Finally, transcription and translation in vitroof the cDNA corresponding to εBP yielded a polypeptide containing carbohydrate-binding activity. All of these results strongly support the conclusion that CBP35 and εBP are mouse and rat homologues, respectively. |
| Databáze: |
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