1c9y: Difference between revisions
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==HUMAN ORNITHINE TRANSCARBAMYLASE: CRYSTALLOGRAPHIC INSIGHTS INTO SUBSTRATE RECOGNITION AND CATALYTIC MECHANISM== | ==HUMAN ORNITHINE TRANSCARBAMYLASE: CRYSTALLOGRAPHIC INSIGHTS INTO SUBSTRATE RECOGNITION AND CATALYTIC MECHANISM== | ||
<StructureSection load='1c9y' size='340' side='right' caption='[[1c9y]], [[Resolution|resolution]] 1.90Å' scene=''> | <StructureSection load='1c9y' size='340' side='right'caption='[[1c9y]], [[Resolution|resolution]] 1.90Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1c9y]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C9Y OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1C9Y FirstGlance]. <br> | <table><tr><td colspan='2'>[[1c9y]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C9Y OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1C9Y FirstGlance]. <br> | ||
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Check<jmol> | Check<jmol> | ||
<jmolCheckbox> | <jmolCheckbox> | ||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/c9/1c9y_consurf.spt"</scriptWhenChecked> | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/c9/1c9y_consurf.spt"</scriptWhenChecked> | ||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | ||
<text>to colour the structure by Evolutionary Conservation</text> | <text>to colour the structure by Evolutionary Conservation</text> | ||
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__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Large Structures]] | |||
[[Category: Ornithine carbamoyltransferase]] | [[Category: Ornithine carbamoyltransferase]] | ||
[[Category: Allewell, N M]] | [[Category: Allewell, N M]] |
Revision as of 10:14, 29 May 2019
HUMAN ORNITHINE TRANSCARBAMYLASE: CRYSTALLOGRAPHIC INSIGHTS INTO SUBSTRATE RECOGNITION AND CATALYTIC MECHANISMHUMAN ORNITHINE TRANSCARBAMYLASE: CRYSTALLOGRAPHIC INSIGHTS INTO SUBSTRATE RECOGNITION AND CATALYTIC MECHANISM
Structural highlights
Disease[OTC_HUMAN] Defects in OTC are the cause of ornithine carbamoyltransferase deficiency (OTCD) [MIM:311250]. OTCD is an X-linked disorder of the urea cycle which causes a form of hyperammonemia. Mutations with no residual enzyme activity are always expressed in hemizygote males by a very severe neonatal hyperammonemic coma that generally proves to be fatal. Heterozygous females are either asymptomatic or express orotic aciduria spontaneously or after protein intake. The disorder is treatable with supplemental dietary arginine and low protein diet. The arbitrary classification of patients into the 'neonatal' group (clinical hyperammonemia in the first few days of life) and 'late' onset (clinical presentation after the neonatal period) has been used to differentiate severe from mild forms.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [:][15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [:][25] [26] [27] [28] Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of human ornithine transcarbamylase (OTCase) complexed with carbamoyl phosphate (CP) and L-norvaline (NOR) has been determined to 1.9-A resolution. There are significant differences in the interactions of CP with the protein, compared with the interactions of the CP moiety of the bisubstrate analogue N-(phosphonoacetyl)-L-ornithine (PALO). The carbonyl plane of CP rotates about 60 degrees compared with the equivalent plane in PALO complexed with OTCase. This positions the side chain of NOR optimally to interact with the carbonyl carbon of CP. The mixed-anhydride oxygen of CP, which is analogous to the methylene group in PALO, interacts with the guanidinium group of Arg-92; the primary carbamoyl nitrogen interacts with the main-chain carbonyl oxygens of Cys-303 and Leu-304, the side chain carbonyl oxygen of Gln-171, and the side chain of Arg-330. The residues that interact with NOR are similar to the residues that interact with the ornithine (ORN) moiety of PALO. The side chain of NOR is well defined and close to the side chain of Cys-303 with the side chains of Leu-163, Leu-200, Met-268, and Pro-305 forming a hydrophobic wall. C-delta of NOR is close to the carbonyl oxygen of Leu-304 (3.56 A), S-gamma atom of Cys-303 (4.19 A), and carbonyl carbon of CP (3.28 A). Even though the N-epsilon atom of ornithine is absent in this structure, the side chain of NOR is positioned to enable the N-epsilon of ornithine to donate a hydrogen to the S-gamma atom of Cys-303 along the reaction pathway. Binding of CP and NOR promotes domain closure to the same degree as PALO, and the active site structure of CP-NOR-enzyme complex is similar to that of the PALO-enzyme complex. The structures of the active sites in the complexes of aspartate transcarbamylase (ATCase) with various substrates or inhibitors are similar to this OTCase structure, consistent with their common evolutionary origin. Crystal structure of human ornithine transcarbamylase complexed with carbamoyl phosphate and L-norvaline at 1.9 A resolution.,Shi D, Morizono H, Aoyagi M, Tuchman M, Allewell NM Proteins. 2000 Jun 1;39(4):271-7. PMID:10813810[29] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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