6q3x

From Proteopedia

(Difference between revisions)

Revision as of 11:52, 24 January 2024

Structure of human galactokinase in complex with galactose and 2'-(benzo[d]oxazol-2-ylamino)-7',8'-dihydro-1'H-spiro[cyclohexane-1,4'-quinazolin]-5'(6'H)-one

Structural highlights

6q3x is a 2 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 2.1Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

GALK1_HUMAN Defects in GALK1 are the cause of galactosemia II (GALCT2) [MIM:230200. Galactosemia II is an autosomal recessive deficiency characterized by congenital cataracts during infancy and presenile cataracts in the adult population. The cataracts are secondary to accumulation of galactitol in the lenses.^[1] ^[2] ^[3] ^[4] ^[5] ^[6]

Function

GALK1_HUMAN Major enzyme for galactose metabolism.

Publication Abstract from PubMed

Classic galactosemia is caused by loss-of-function mutations in galactose-1-phosphate uridylyltransferase (GALT) that lead to toxic accumulation of its substrate, galactose-1-phosphate. One proposed therapy is to inhibit the biosynthesis of galactose-1-phosphate, catalyzed by galactokinase 1 (GALK1). Existing inhibitors of human GALK1 (hGALK1) are primarily ATP-competitive with limited clinical utility to date. Here, we determined crystal structures of hGALK1 bound with reported ATP-competitive inhibitors of the spiro-benzoxazole series, to reveal their binding mode in the active site. Spurred by the need for additional chemotypes of hGALK1 inhibitors, desirably targeting a nonorthosteric site, we also performed crystallography-based screening by soaking hundreds of hGALK1 crystals, already containing active site ligands, with fragments from a custom library. Two fragments were found to bind close to the ATP binding site, and a further eight were found in a hotspot distal from the active site, highlighting the strength of this method in identifying previously uncharacterized allosteric sites. To generate inhibitors of improved potency and selectivity targeting the newly identified binding hotspot, new compounds were designed by merging overlapping fragments. This yielded two micromolar inhibitors of hGALK1 that were not competitive with respect to either substrate (ATP or galactose) and demonstrated good selectivity over hGALK1 homologues, galactokinase 2 and mevalonate kinase. Our findings are therefore the first to demonstrate inhibition of hGALK1 from an allosteric site, with potential for further development of potent and selective inhibitors to provide novel therapeutics for classic galactosemia.

Fragment Screening Reveals Starting Points for Rational Design of Galactokinase 1 Inhibitors to Treat Classic Galactosemia.,Mackinnon SR, Krojer T, Foster WR, Diaz-Saez L, Tang M, Huber KVM, von Delft F, Lai K, Brennan PE, Arruda Bezerra G, Yue WW ACS Chem Biol. 2021 Mar 16. doi: 10.1021/acschembio.0c00498. PMID:33724769^[7]

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

References

↑ Kalaydjieva L, Perez-Lezaun A, Angelicheva D, Onengut S, Dye D, Bosshard NU, Jordanova A, Savov A, Yanakiev P, Kremensky I, Radeva B, Hallmayer J, Markov A, Nedkova V, Tournev I, Aneva L, Gitzelmann R. A founder mutation in the GK1 gene is responsible for galactokinase deficiency in Roma (Gypsies). Am J Hum Genet. 1999 Nov;65(5):1299-307. PMID:10521295 doi:S0002-9297(07)62136-3
↑ Kolosha V, Anoia E, de Cespedes C, Gitzelmann R, Shih L, Casco T, Saborio M, Trejos R, Buist N, Tedesco T, Skach W, Mitelmann O, Ledee D, Huang K, Stambolian D. Novel mutations in 13 probands with galactokinase deficiency. Hum Mutat. 2000;15(5):447-53. PMID:10790206 doi:<447::AID-HUMU6>3.0.CO;2-M 10.1002/(SICI)1098-1004(200005)15:5<447::AID-HUMU6>3.0.CO;2-M
↑ Okano Y, Asada M, Fujimoto A, Ohtake A, Murayama K, Hsiao KJ, Choeh K, Yang Y, Cao Q, Reichardt JK, Niihira S, Imamura T, Yamano T. A genetic factor for age-related cataract: identification and characterization of a novel galactokinase variant, "Osaka," in Asians. Am J Hum Genet. 2001 Apr;68(4):1036-42. Epub 2001 Feb 23. PMID:11231902 doi:S0002-9297(07)61428-1
↑ Hunter M, Angelicheva D, Levy HL, Pueschel SM, Kalaydjieva L. Novel mutations in the GALK1 gene in patients with galactokinase deficiency. Hum Mutat. 2001;17(1):77-8. PMID:11139256 doi:<77::AID-HUMU20>3.0.CO;2-H 10.1002/1098-1004(2001)17:1<77::AID-HUMU20>3.0.CO;2-H
↑ Timson DJ, Reece RJ. Functional analysis of disease-causing mutations in human galactokinase. Eur J Biochem. 2003 Apr;270(8):1767-74. PMID:12694189
↑ Sangiuolo F, Magnani M, Stambolian D, Novelli G. Biochemical characterization of two GALK1 mutations in patients with galactokinase deficiency. Hum Mutat. 2004 Apr;23(4):396. PMID:15024738 doi:10.1002/humu.9223
↑ Mackinnon SR, Krojer T, Foster WR, Diaz-Saez L, Tang M, Huber KVM, von Delft F, Lai K, Brennan PE, Arruda Bezerra G, Yue WW. Fragment Screening Reveals Starting Points for Rational Design of Galactokinase 1 Inhibitors to Treat Classic Galactosemia. ACS Chem Biol. 2021 Mar 16. doi: 10.1021/acschembio.0c00498. PMID:33724769 doi:http://dx.doi.org/10.1021/acschembio.0c00498

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

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/6q3x"

@@ Line 1: / Line 1: @@
 ==Structure of human galactokinase in complex with galactose and 2'-(benzo[d]oxazol-2-ylamino)-7',8'-dihydro-1'H-spiro[cyclohexane-1,4'-quinazolin]-5'(6'H)-one==
-<StructureSection load='6q3x' size='340' side='right'caption='[[6q3x]]' scene=''>
+<StructureSection load='6q3x' size='340' side='right'caption='[[6q3x]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
 == Structural highlights ==
-<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6Q3X OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6Q3X FirstGlance]. <br>
+<table><tr><td colspan='2'>[[6q3x]] is a 2 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=6Q3X OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6Q3X FirstGlance]. <br>
-</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=6q3x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6q3x OCA], [https://pdbe.org/6q3x PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6q3x RCSB], [https://www.ebi.ac.uk/pdbsum/6q3x PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6q3x ProSAT]</span></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]] 2.1&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=HFK:2-(1,3-benzoxazol-2-ylamino)spiro[1,6,7,8-tetrahydroquinazoline-4,1-cyclohexane]-5-one'>HFK</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</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=6q3x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6q3x OCA], [https://pdbe.org/6q3x PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6q3x RCSB], [https://www.ebi.ac.uk/pdbsum/6q3x PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6q3x ProSAT]</span></td></tr>
 </table>
+== Disease ==
+[https://www.uniprot.org/uniprot/GALK1_HUMAN GALK1_HUMAN] Defects in GALK1 are the cause of galactosemia II (GALCT2) [MIM:[https://omim.org/entry/230200 230200]. Galactosemia II is an autosomal recessive deficiency characterized by congenital cataracts during infancy and presenile cataracts in the adult population. The cataracts are secondary to accumulation of galactitol in the lenses.<ref>PMID:10521295</ref> <ref>PMID:10790206</ref> <ref>PMID:11231902</ref> <ref>PMID:11139256</ref> <ref>PMID:12694189</ref> <ref>PMID:15024738</ref>
+== Function ==
+[https://www.uniprot.org/uniprot/GALK1_HUMAN GALK1_HUMAN] Major enzyme for galactose metabolism.
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Classic galactosemia is caused by loss-of-function mutations in galactose-1-phosphate uridylyltransferase (GALT) that lead to toxic accumulation of its substrate, galactose-1-phosphate. One proposed therapy is to inhibit the biosynthesis of galactose-1-phosphate, catalyzed by galactokinase 1 (GALK1). Existing inhibitors of human GALK1 (hGALK1) are primarily ATP-competitive with limited clinical utility to date. Here, we determined crystal structures of hGALK1 bound with reported ATP-competitive inhibitors of the spiro-benzoxazole series, to reveal their binding mode in the active site. Spurred by the need for additional chemotypes of hGALK1 inhibitors, desirably targeting a nonorthosteric site, we also performed crystallography-based screening by soaking hundreds of hGALK1 crystals, already containing active site ligands, with fragments from a custom library. Two fragments were found to bind close to the ATP binding site, and a further eight were found in a hotspot distal from the active site, highlighting the strength of this method in identifying previously uncharacterized allosteric sites. To generate inhibitors of improved potency and selectivity targeting the newly identified binding hotspot, new compounds were designed by merging overlapping fragments. This yielded two micromolar inhibitors of hGALK1 that were not competitive with respect to either substrate (ATP or galactose) and demonstrated good selectivity over hGALK1 homologues, galactokinase 2 and mevalonate kinase. Our findings are therefore the first to demonstrate inhibition of hGALK1 from an allosteric site, with potential for further development of potent and selective inhibitors to provide novel therapeutics for classic galactosemia.
+Fragment Screening Reveals Starting Points for Rational Design of Galactokinase 1 Inhibitors to Treat Classic Galactosemia.,Mackinnon SR, Krojer T, Foster WR, Diaz-Saez L, Tang M, Huber KVM, von Delft F, Lai K, Brennan PE, Arruda Bezerra G, Yue WW ACS Chem Biol. 2021 Mar 16. doi: 10.1021/acschembio.0c00498. PMID:33724769<ref>PMID:33724769</ref>
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
+</div>
+<div class="pdbe-citations 6q3x" style="background-color:#fffaf0;"></div>
 ==See Also==
 *[[Galactokinase|Galactokinase]]
+== References ==
+<references/>
 __TOC__
 </StructureSection>
+[[Category: Homo sapiens]]
 [[Category: Large Structures]]
 [[Category: Arrowsmith C]]

6q3x

From Proteopedia

Revision as of 11:52, 24 January 2024

Structure of human galactokinase in complex with galactose and 2'-(benzo[d]oxazol-2-ylamino)-7',8'-dihydro-1'H-spiro[cyclohexane-1,4'-quinazolin]-5'(6'H)-one

Structural highlights

Disease

Function

Publication Abstract from PubMed

See Also

References

Contents

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