Summary for 2Q3N
| Entry DOI | 10.2210/pdb2q3n/pdb |
| Descriptor | Agglutinin-1 A chain, Agglutinin-1 B chain, 2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total) |
| Functional Keywords | ribosome-inactivating protein, immunotoxin, agglutinin abrin, plant protein |
| Biological source | Abrus precatorius (Indian licorice) More |
| Total number of polymer chains | 2 |
| Total formula weight | 59579.08 |
| Authors | Bagaria, A.,Surendranath, K.,Ramagopal, U.A.,Ramakumar, S.,Karande, A.A. (deposition date: 2007-05-30, release date: 2007-06-26, Last modification date: 2024-10-30) |
| Primary citation | Bagaria, A.,Surendranath, K.,Ramagopal, U.A.,Ramakumar, S.,Karande, A.A. Structure-Function Analysis and Insights into the Reduced Toxicity of Abrus precatorius Agglutinin I in Relation to Abrin. J.Biol.Chem., 281:34465-34474, 2006 Cited by PubMed Abstract: Abrin and agglutinin-I from the seeds of Abrus precatorius are type II ribosome-inactivating proteins that inhibit protein synthesis in eukaryotic cells. The two toxins share a high degree of sequence similarity; however, agglutinin-I is weaker in its activity. We compared the kinetics of protein synthesis inhibition by abrin and agglutinin-I in two different cell lines and found that approximately 200-2000-fold higher concentration of agglutinin-I is needed for the same degree of inhibition. Like abrin, agglutinin-I also induced apoptosis in the cells by triggering the intrinsic mitochondrial pathway, although at higher concentrations as compared with abrin. The reason for the decreased toxicity of agglutinin-I became apparent on the analysis of the crystal structure of agglutinin-I obtained by us in comparison with that of the reported structure of abrin. The overall protein folding of agglutinin-I is similar to that of abrin-a with a single disulfide bond holding the toxic A subunit and the lectin-like B-subunit together, constituting a heterodimer. However, there are significant differences in the secondary structural elements, mostly in the A chain. The substitution of Asn-200 in abrin-a with Pro-199 in agglutinin-I seems to be a major cause for the decreased toxicity of agglutinin-I. This perhaps is not a consequence of any kink formation by a proline residue in the helical segment, as reported by others earlier, but due to fewer interactions that proline can possibly have with the bound substrate. PubMed: 16772301DOI: 10.1074/jbc.M601777200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.5 Å) |
Structure validation
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