| Autor: |
Chen, Lan X., Zhang, Zhen-ping, Scafonas, Angela, Cavalli, R.Christopher, Gabriel, Jerome L., Soprano, Kenneth J., Soprano, Dianne Robert |
| Zdroj: |
Journal of Biological Chemistry; March 1995, Vol. 270 Issue: 9 p4518-4525, 8p |
| Abstrakt: |
Cellular retinoic acid-binding protein type II (CRABP-II) is one of two small molecular weight, cytosolic proteins which specifically bind retinoic acid (RA). Crystallographic and site-directed mutagenesis studies of several related proteins have indicated that either one or two conserved amino acid residues, homologous to positions Arg111and Arg132of CRABP-II, are important for the binding of the hydrophobic ligand. In this report we have prepared site-directed mutations of these two positions of CRABP-II, Arg111and Arg132, as well as Lys82to determine the role of these residues in the binding of RA. Recombinant wild type and mutant CRABP-II proteins were expressed and purified, and the affinity for retinoids was determined by fluorometric titration and binding of 3H-labeled compounds. K82A displayed an identical Kdfor all-trans-RA as wild type CRABP-II and the Kdfor all-trans-RA of R111A was only slightly higher. On the other hand, the two Arg132mutants, R132A and R132Q, of CRABP-II demonstrated undetectable binding of all-trans-RA. Taken together these data demonstrate that Arg132is a critical amino acid residue for the binding of RA by CRABP-II. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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