View source for 2brn


==Structure-based Design of Novel Chk1 Inhibitors: Insights into Hydrogen Bonding and Protein-Ligand Affinity==
<StructureSection load='2brn' size='340' side='right'caption='[[2brn]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2brn]] is a 1 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=2BRN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BRN FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DF1:(2R)-1-[(5,6-DIPHENYL-7H-PYRROLO[2,3-D]PYRIMIDIN-4-YL)AMINO]PROPAN-2-OL'>DF1</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=2brn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2brn OCA], [https://pdbe.org/2brn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2brn RCSB], [https://www.ebi.ac.uk/pdbsum/2brn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2brn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CHK1_HUMAN CHK1_HUMAN] Serine/threonine-protein kinase which is required for checkpoint-mediated cell cycle arrest and activation of DNA repair in response to the presence of DNA damage or unreplicated DNA. May also negatively regulate cell cycle progression during unperturbed cell cycles. This regulation is achieved by a number of mechanisms that together help to preserve the integrity of the genome. Recognizes the substrate consensus sequence [R-X-X-S/T]. Binds to and phosphorylates CDC25A, CDC25B and CDC25C. Phosphorylation of CDC25A at 'Ser-178' and 'Thr-507' and phosphorylation of CDC25C at 'Ser-216' creates binding sites for 14-3-3 proteins which inhibit CDC25A and CDC25C. Phosphorylation of CDC25A at 'Ser-76', 'Ser-124', 'Ser-178', 'Ser-279' and 'Ser-293' promotes proteolysis of CDC25A. Phosphorylation of CDC25A at 'Ser-76' primes the protein for subsequent phosphorylation at 'Ser-79', 'Ser-82' and 'Ser-88' by NEK11, which is required for polyubiquitination and degradation of CDCD25A. Inhibition of CDC25 leads to increased inhibitory tyrosine phosphorylation of CDK-cyclin complexes and blocks cell cycle progression. Also phosphorylates NEK6. Binds to and phosphorylates RAD51 at 'Thr-309', which promotes the release of RAD51 from BRCA2 and enhances the association of RAD51 with chromatin, thereby promoting DNA repair by homologous recombination. Phosphorylates multiple sites within the C-terminus of TP53, which promotes activation of TP53 by acetylation and promotes cell cycle arrest and suppression of cellular proliferation. Also promotes repair of DNA cross-links through phosphorylation of FANCE. Binds to and phosphorylates TLK1 at 'Ser-743', which prevents the TLK1-dependent phosphorylation of the chromatin assembly factor ASF1A. This may enhance chromatin assembly both in the presence or absence of DNA damage. May also play a role in replication fork maintenance through regulation of PCNA. May regulate the transcription of genes that regulate cell-cycle progression through the phosphorylation of histones. Phosphorylates histone H3.1 (to form H3T11ph), which leads to epigenetic inhibition of a subset of genes. May also phosphorylate RB1 to promote its interaction with the E2F family of transcription factors and subsequent cell cycle arrest.<ref>PMID:9278511</ref> <ref>PMID:10673501</ref> <ref>PMID:11535615</ref> <ref>PMID:12446774</ref> <ref>PMID:12399544</ref> <ref>PMID:12676583</ref> <ref>PMID:12660173</ref> <ref>PMID:14681206</ref> <ref>PMID:12676925</ref> <ref>PMID:12759351</ref> <ref>PMID:14559997</ref> <ref>PMID:14988723</ref> <ref>PMID:15311285</ref> <ref>PMID:15659650</ref> <ref>PMID:15665856</ref> <ref>PMID:15650047</ref> <ref>PMID:16511572</ref> <ref>PMID:16963448</ref> <ref>PMID:17380128</ref> <ref>PMID:17296736</ref> <ref>PMID:18510930</ref> <ref>PMID:18728393</ref> <ref>PMID:18451105</ref> <ref>PMID:18317453</ref> <ref>PMID:19734889</ref> <ref>PMID:20090422</ref>   Isoform 2: Endogenous repressor of isoform 1, interacts with, and antagonizes CHK1 to promote the S to G2/M phase transition.<ref>PMID:9278511</ref> <ref>PMID:10673501</ref> <ref>PMID:11535615</ref> <ref>PMID:12446774</ref> <ref>PMID:12399544</ref> <ref>PMID:12676583</ref> <ref>PMID:12660173</ref> <ref>PMID:14681206</ref> <ref>PMID:12676925</ref> <ref>PMID:12759351</ref> <ref>PMID:14559997</ref> <ref>PMID:14988723</ref> <ref>PMID:15311285</ref> <ref>PMID:15659650</ref> <ref>PMID:15665856</ref> <ref>PMID:15650047</ref> <ref>PMID:16511572</ref> <ref>PMID:16963448</ref> <ref>PMID:17380128</ref> <ref>PMID:17296736</ref> <ref>PMID:18510930</ref> <ref>PMID:18728393</ref> <ref>PMID:18451105</ref> <ref>PMID:18317453</ref> <ref>PMID:19734889</ref> <ref>PMID:20090422</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/br/2brn_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2brn ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
We report the discovery, synthesis, and crystallographic binding mode of novel furanopyrimidine and pyrrolopyrimidine inhibitors of the Chk1 kinase, an oncology target. These inhibitors are synthetically tractable and inhibit Chk1 by competing for its ATP site. A chronological account allows an objective comparison of modeled compound docking modes to the subsequently obtained crystal structures. The comparison provides insights regarding the interpretation of modeling results, in relationship to the multiple reasonable docking modes which may be obtained in a kinase-ATP site. The crystal structures were used to guide medicinal chemistry efforts. This led to a thorough characterization of a pair of ligand-protein complexes which differ by a single hydrogen bond. An analysis indicates that this hydrogen bond is expected to contribute a fraction of the 10-fold change in binding affinity, adding a valuable observation to the debate about the energetic role of hydrogen bonding in molecular recognition.

Structure-based design of novel Chk1 inhibitors: insights into hydrogen bonding and protein-ligand affinity.,Foloppe N, Fisher LM, Howes R, Kierstan P, Potter A, Robertson AG, Surgenor AE J Med Chem. 2005 Jun 30;48(13):4332-45. PMID:15974586<ref>PMID:15974586</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2brn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Serine/threonine protein kinase 3D structures|Serine/threonine protein kinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Fisher LM]]
[[Category: Foloppe N]]
[[Category: Howes R]]
[[Category: Kierstan P]]
[[Category: Potter A]]
[[Category: Robertson AGS]]
[[Category: Surgenor AE]]