2mas: Difference between revisions

Revision as of 09:31, 4 May 2008

PURINE NUCLEOSIDE HYDROLASE WITH A TRANSITION STATE INHIBITOR

OverviewOverview

Nucleoside N-ribohydrolases are targets for disruption of purine salvage in the protozoan parasites. The structure of a trypanosomal N-ribohydrolase in complex with a transition-state inhibitor is reported at 2.3 A resolution. The nonspecific nucleoside hydrolase from Crithidia fasciculata cocrystallized with p-aminophenyliminoribitol reveals tightly bound Ca2+ as a catalytic site ligand. The complex with the transition-state inhibitor is characterized by (1) large protein conformational changes to create a hydrophobic leaving group site (2) C3'-exo geometry for the inhibitor, typical of a ribooxocarbenium ion (3) stabilization of the ribooxocarbenium analogue between the neighboring group 5'-hydroxyl and bidentate hydrogen bonds to Asn168; and (4) octacoordinate Ca2+ orients a catalytic site water and is liganded to two hydroxyls of the inhibitor. The mechanism is ribooxocarbenium stabilization with weak leaving group activation and is a departure from glucohydrolases which use paired carboxylates to achieve the transition state.

About this StructureAbout this Structure

2MAS is a Single protein structure of sequence from Crithidia fasciculata. Full crystallographic information is available from OCA.

ReferenceReference

Trypanosomal nucleoside hydrolase. A novel mechanism from the structure with a transition-state inhibitor., Degano M, Almo SC, Sacchettini JC, Schramm VL, Biochemistry. 1998 May 5;37(18):6277-85. PMID:9572842 Page seeded by OCA on Sun May 4 09:31:46 2008

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

OCA

@@ Line 1: / Line 1: @@
 [[Image:2mas.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 2mas |SIZE=350|CAPTION= <scene name='initialview01'>2mas</scene>, resolution 2.3&Aring;
+The line below this paragraph, containing "STRUCTURE_2mas", creates the "Structure Box" on the page.
-|SITE= <scene name='pdbsite=S1:Description+Not+Provided'>S1</scene>, <scene name='pdbsite=S2:Description+Not+Provided'>S2</scene>, <scene name='pdbsite=S3:Description+Not+Provided'>S3</scene> and <scene name='pdbsite=S4:Description+Not+Provided'>S4</scene>
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=PIR:2-(4-AMINO-PHENYL)-5-HYDROXYMETHYL-PYRROLIDINE-3,4-DIOL'>PIR</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Purine_nucleosidase Purine nucleosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.1 3.2.2.1] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= IU-NH FROM C. FASCICULATA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=5656 Crithidia fasciculata])
+-->
-|DOMAIN=
+{{STRUCTURE_2mas|  PDB=2mas  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2mas FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2mas OCA], [http://www.ebi.ac.uk/pdbsum/2mas PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2mas RCSB]</span>
-}}
 '''PURINE NUCLEOSIDE HYDROLASE WITH A TRANSITION STATE INHIBITOR'''
@@ Line 29: / Line 26: @@
 [[Category: Sacchettini, J C.]]
 [[Category: Schramm, V L.]]
-[[Category: hydrolase]]
+[[Category: Hydrolase]]
-[[Category: inosine]]
+[[Category: Inosine]]
-[[Category: iu-nh]]
+[[Category: Iu-nh]]
-[[Category: purine nucleosidase]]
+[[Category: Purine nucleosidase]]
-[[Category: purine nucleoside hydrolase]]
+[[Category: Purine nucleoside hydrolase]]
-[[Category: uridine]]
+[[Category: Uridine]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 09:31:46 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:03:47 2008''