1abr: Difference between revisions

Revision as of 10:04, 2 May 2008

CRYSTAL STRUCTURE OF ABRIN-A

OverviewOverview

The crystal structure of abrin-a, a type II ribosome-inactivating protein from the seeds of Abrus precatorius, has been determined from a novel crystalline form by the molecular replacement method using the coordinates of ricin. The structure has been refined at 2.14 A to a R-factor of 18.9%. The root-mean-square deviations of bond lengths and angles from the standard values are 0.013 A and 1.82 degrees, respectively. The overall protein folding is similar to that of ricin, but there are differences in the secondary structure, mostly of the A-chain. Several parts of the molecular surface differ significantly; some of them are quite near the active site cleft, and probably influence ribosome recognition. The positions of invariant active site residues remain the same, except the position of Tyr74. Two water molecules of hydrogen-bonded active site residues have been located in the active site cleft. Both of them may be responsible for hydrolyzing the N-C glycosidic bond. The current abrin-a structure is lactose free; this is probably essential for abrin-a crystallization. The B-chain is a glycoprotein, and the positions of several sugar residues of two sugar chains linked to earlier predicted glycosylation sites were determined. One of the sugar chains is a bridge between two neighboring molecules, since one of its mannose residues is connected to the galactose binding site of the neighboring molecule. Another sugar chain covers the surface of the B-chain.

About this StructureAbout this Structure

1ABR is a Protein complex structure. Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure of abrin-a at 2.14 A., Tahirov TH, Lu TH, Liaw YC, Chen YL, Lin JY, J Mol Biol. 1995 Jul 14;250(3):354-67. PMID:7608980 Page seeded by OCA on Fri May 2 10:04:44 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 [[Image:1abr.gif|left|200px]]
- {{Structure
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+The line below this paragraph, containing "STRUCTURE_1abr", creates the "Structure Box" on the page.
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-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1abr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1abr OCA], [http://www.ebi.ac.uk/pdbsum/1abr PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1abr RCSB]</span>
-}}
 '''CRYSTAL STRUCTURE OF ABRIN-A'''
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 ==About this Structure==
-ABR is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ABR OCA].
+ABR is a [[Protein complex]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ABR OCA].
 ==Reference==
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 [[Category: Lu, T H.]]
 [[Category: Tahirov, T H.]]
-[[Category: complex (glycosidase/carbohydrate)]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 10:04:44 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:37:08 2008''