2q3n
From Proteopedia
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[[Image:2q3n.gif|left|200px]] | [[Image:2q3n.gif|left|200px]] | ||
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| - | | | + | {{STRUCTURE_2q3n| PDB=2q3n | SCENE= }} |
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'''Agglutinin from Abrus Precatorius (APA-I)''' | '''Agglutinin from Abrus Precatorius (APA-I)''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2Q3N is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Abrus_precatorius Abrus precatorius]. This structure supersedes the now removed PDB entry | + | 2Q3N is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Abrus_precatorius Abrus precatorius]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=2amz 2amz]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2Q3N OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Abrus precatorius]] | [[Category: Abrus precatorius]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: | + | [[Category: RRNA N-glycosylase]] |
[[Category: Bagaria, A.]] | [[Category: Bagaria, A.]] | ||
[[Category: Karande, A A.]] | [[Category: Karande, A A.]] | ||
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[[Category: Ramakumar, S.]] | [[Category: Ramakumar, S.]] | ||
[[Category: Surendranath, K.]] | [[Category: Surendranath, K.]] | ||
| - | [[Category: | + | [[Category: Agglutinin abrin]] |
| - | [[Category: | + | [[Category: Immunotoxin]] |
| - | [[Category: | + | [[Category: Ribosome-inactivating protein]] |
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Revision as of 11:16, 4 May 2008
Agglutinin from Abrus Precatorius (APA-I)
Overview
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.
About this Structure
2Q3N is a Protein complex structure of sequences from Abrus precatorius. This structure supersedes the now removed PDB entry 2amz. Full crystallographic information is available from OCA.
Reference
Structure-function analysis and insights into the reduced toxicity of Abrus precatorius agglutinin I in relation to abrin., Bagaria A, Surendranath K, Ramagopal UA, Ramakumar S, Karande AA, J Biol Chem. 2006 Nov 10;281(45):34465-74. Epub 2006 Jun 13. PMID:16772301 Page seeded by OCA on Sun May 4 14:16:04 2008
