8ez1

From Proteopedia

(Difference between revisions)

Current revision

Human Ornithine Aminotransferase (hOAT) co-crystallized with its inactivator 3-Amino-4-fluorocyclopentenecarboxylic Acid

Structural highlights

8ez1 is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.91Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

OAT_HUMAN Defects in OAT are the cause of hyperornithinemia with gyrate atrophy of choroid and retina (HOGA) [MIM:258870. HOGA is a slowly progressive blinding autosomal recessive disorder.^[1] ^[2] ^[3] ^[4] ^[5] ^[6]

Function

OAT_HUMAN

Publication Abstract from PubMed

Ornithine aminotransferase (OAT) is overexpressed in hepatocellular carcinoma (HCC), and we previously showed that inactivation of OAT inhibits the growth of HCC. Recently, we found that (3S,4S)-3-amino-4-fluorocyclopentenecarboxylic acid (5) was a potent inactivator of gamma-aminobutyric acid aminotransferase (GABA-AT), proceeding by an enamine mechanism. Here we describe our investigations into the activity and mechanism of 5 as an inactivator of human OAT. We have found that 5 exhibits 10-fold less inactivation efficiency (k(inact)/K(I)) against hOAT than GABA-AT. A comprehensive mechanistic study was carried out to understand its inactivation mechanism with hOAT. pK(a) and electrostatic potential calculations were performed to further support the notion that the alpha,beta-unsaturated alkene of 5 is critical for enhancing acidity and nucleophilicity of the corresponding intermediates and ultimately responsible for the improved inactivation efficiency of 5 over the corresponding saturated analogue (4). Intact protein mass spectrometry and the crystal structure complex with hOAT provide evidence to conclude that 5 mainly inactivates hOAT through noncovalent interactions, and that, unlike with GABA-AT, covalent binding with hOAT is a minor component of the total inhibition which is unique relative to other monofluoro-substituted derivatives. Furthermore, based on the results of transient-state measurements and free energy calculations, it is suggested that the alpha,beta-unsaturated carboxylate group of PLP-bound 5 may be directly involved in the inactivation cascade by forming an enolate intermediate. Overall, compound 5 exhibits unusual structural conversions which are catalyzed by specific residues within hOAT, ultimately leading to an enamine mechanism-based inactivation of hOAT through noncovalent interactions and covalent modification.

Structural and Mechanistic Basis for the Inactivation of Human Ornithine Aminotransferase by (3S,4S)-3-Amino-4-fluorocyclopentenecarboxylic Acid.,Shen S, Butrin A, Beaupre BA, Ferreira GM, Doubleday PF, Grass DH, Zhu W, Kelleher NL, Moran GR, Liu D, Silverman RB Molecules. 2023 Jan 23;28(3):1133. doi: 10.3390/molecules28031133. PMID:36770800^[7]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Ramesh V, McClatchey AI, Ramesh N, Benoit LA, Berson EL, Shih VE, Gusella JF. Molecular basis of ornithine aminotransferase deficiency in B-6-responsive and -nonresponsive forms of gyrate atrophy. Proc Natl Acad Sci U S A. 1988 Jun;85(11):3777-80. PMID:3375240
↑ Inana G, Chambers C, Hotta Y, Inouye L, Filpula D, Pulford S, Shiono T. Point mutation affecting processing of the ornithine aminotransferase precursor protein in gyrate atrophy. J Biol Chem. 1989 Oct 15;264(29):17432-6. PMID:2793865
↑ Michaud J, Brody LC, Steel G, Fontaine G, Martin LS, Valle D, Mitchell G. Strand-separating conformational polymorphism analysis: efficacy of detection of point mutations in the human ornithine delta-aminotransferase gene. Genomics. 1992 Jun;13(2):389-94. PMID:1612597
↑ Brody LC, Mitchell GA, Obie C, Michaud J, Steel G, Fontaine G, Robert MF, Sipila I, Kaiser-Kupfer M, Valle D. Ornithine delta-aminotransferase mutations in gyrate atrophy. Allelic heterogeneity and functional consequences. J Biol Chem. 1992 Feb 15;267(5):3302-7. PMID:1737786
↑ Michaud J, Thompson GN, Brody LC, Steel G, Obie C, Fontaine G, Schappert K, Keith CG, Valle D, Mitchell GA. Pyridoxine-responsive gyrate atrophy of the choroid and retina: clinical and biochemical correlates of the mutation A226V. Am J Hum Genet. 1995 Mar;56(3):616-22. PMID:7887415
↑ Kobayashi T, Ogawa H, Kasahara M, Shiozawa Z, Matsuzawa T. A single amino acid substitution within the mature sequence of ornithine aminotransferase obstructs mitochondrial entry of the precursor. Am J Hum Genet. 1995 Aug;57(2):284-91. PMID:7668253
↑ Shen S, Butrin A, Beaupre BA, Ferreira GM, Doubleday PF, Grass DH, Zhu W, Kelleher NL, Moran GR, Liu D, Silverman RB. Structural and Mechanistic Basis for the Inactivation of Human Ornithine Aminotransferase by (3S,4S)-3-Amino-4-fluorocyclopentenecarboxylic Acid. Molecules. 2023 Jan 23;28(3):1133. PMID:36770800 doi:10.3390/molecules28031133

1 Structural highlights
2 Disease
3 Function
4 Publication Abstract from PubMed
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/8ez1"

@@ Line 4: / Line 4: @@
 == Structural highlights ==
 <table><tr><td colspan='2'>[[8ez1]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8EZ1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8EZ1 FirstGlance]. <br>
-</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=X8B:(3E,4E)-4-({3-hydroxy-2-methyl-5-[(phosphonooxy)methyl]pyridin-4-yl}methylidene)-3-iminocyclopent-1-ene-1-carboxylic+acid'>X8B</scene>, <scene name='pdbligand=X8H:(1R,3S,4Z)-3-({3-hydroxy-2-methyl-5-[(phosphonooxy)methyl]pyridin-4-yl}methyl)-4-iminocyclopentane-1-carboxylic+acid'>X8H</scene></td></tr>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.91&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=X8B:(3E,4E)-4-({3-hydroxy-2-methyl-5-[(phosphonooxy)methyl]pyridin-4-yl}methylidene)-3-iminocyclopent-1-ene-1-carboxylic+acid'>X8B</scene>, <scene name='pdbligand=X8H:(1~{R},4~{S})-3-azanylidene-4-[[2-methyl-3-oxidanyl-5-(phosphonooxymethyl)pyridin-4-yl]methyl]cyclopentane-1-carboxylic+acid'>X8H</scene></td></tr>
 <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8ez1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8ez1 OCA], [https://pdbe.org/8ez1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8ez1 RCSB], [https://www.ebi.ac.uk/pdbsum/8ez1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8ez1 ProSAT]</span></td></tr>
 </table>
@@ Line 11: / Line 12: @@
 == Function ==
 [https://www.uniprot.org/uniprot/OAT_HUMAN OAT_HUMAN]
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Ornithine aminotransferase (OAT) is overexpressed in hepatocellular carcinoma (HCC), and we previously showed that inactivation of OAT inhibits the growth of HCC. Recently, we found that (3S,4S)-3-amino-4-fluorocyclopentenecarboxylic acid (5) was a potent inactivator of gamma-aminobutyric acid aminotransferase (GABA-AT), proceeding by an enamine mechanism. Here we describe our investigations into the activity and mechanism of 5 as an inactivator of human OAT. We have found that 5 exhibits 10-fold less inactivation efficiency (k(inact)/K(I)) against hOAT than GABA-AT. A comprehensive mechanistic study was carried out to understand its inactivation mechanism with hOAT. pK(a) and electrostatic potential calculations were performed to further support the notion that the alpha,beta-unsaturated alkene of 5 is critical for enhancing acidity and nucleophilicity of the corresponding intermediates and ultimately responsible for the improved inactivation efficiency of 5 over the corresponding saturated analogue (4). Intact protein mass spectrometry and the crystal structure complex with hOAT provide evidence to conclude that 5 mainly inactivates hOAT through noncovalent interactions, and that, unlike with GABA-AT, covalent binding with hOAT is a minor component of the total inhibition which is unique relative to other monofluoro-substituted derivatives. Furthermore, based on the results of transient-state measurements and free energy calculations, it is suggested that the alpha,beta-unsaturated carboxylate group of PLP-bound 5 may be directly involved in the inactivation cascade by forming an enolate intermediate. Overall, compound 5 exhibits unusual structural conversions which are catalyzed by specific residues within hOAT, ultimately leading to an enamine mechanism-based inactivation of hOAT through noncovalent interactions and covalent modification.
+Structural and Mechanistic Basis for the Inactivation of Human Ornithine Aminotransferase by (3S,4S)-3-Amino-4-fluorocyclopentenecarboxylic Acid.,Shen S, Butrin A, Beaupre BA, Ferreira GM, Doubleday PF, Grass DH, Zhu W, Kelleher NL, Moran GR, Liu D, Silverman RB Molecules. 2023 Jan 23;28(3):1133. doi: 10.3390/molecules28031133. PMID:36770800<ref>PMID:36770800</ref>
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
+</div>
+<div class="pdbe-citations 8ez1" style="background-color:#fffaf0;"></div>
 == References ==
 <references/>

8ez1

From Proteopedia

Current revision

Human Ornithine Aminotransferase (hOAT) co-crystallized with its inactivator 3-Amino-4-fluorocyclopentenecarboxylic Acid

Structural highlights

Disease

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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