View source for 5ocg


==Discovery of small molecules binding to KRAS via high affinity antibody fragment competition method.==
<StructureSection load='5ocg' size='340' side='right'caption='[[5ocg]], [[Resolution|resolution]] 1.48&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5ocg]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5OCG OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5OCG FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=9R5:[(2~{R})-6-chloranyl-2,3-dihydro-1,4-benzodioxin-2-yl]methanamine'>9R5</scene>, <scene name='pdbligand=GNP:PHOSPHOAMINOPHOSPHONIC+ACID-GUANYLATE+ESTER'>GNP</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">KRAS, KRAS2, RASK2 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ocg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ocg OCA], [http://pdbe.org/5ocg PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5ocg RCSB], [http://www.ebi.ac.uk/pdbsum/5ocg PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5ocg ProSAT]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/RASK_HUMAN RASK_HUMAN]] Defects in KRAS are a cause of acute myelogenous leukemia (AML) [MIM:[http://omim.org/entry/601626 601626]]. AML is a malignant disease in which hematopoietic precursors are arrested in an early stage of development.<ref>PMID:8955068</ref>   Defects in KRAS are a cause of juvenile myelomonocytic leukemia (JMML) [MIM:[http://omim.org/entry/607785 607785]]. JMML is a pediatric myelodysplastic syndrome that constitutes approximately 30% of childhood cases of myelodysplastic syndrome (MDS) and 2% of leukemia. It is characterized by leukocytosis with tissue infiltration and in vitro hypersensitivity of myeloid progenitors to granulocyte-macrophage colony stimulating factor.  Defects in KRAS are the cause of Noonan syndrome type 3 (NS3) [MIM:[http://omim.org/entry/609942 609942]]. Noonan syndrome (NS) [MIM:[http://omim.org/entry/163950 163950]] is a disorder characterized by dysmorphic facial features, short stature, hypertelorism, cardiac anomalies, deafness, motor delay, and a bleeding diathesis. It is a genetically heterogeneous and relatively common syndrome, with an estimated incidence of 1 in 1000-2500 live births. Rarely, NS is associated with juvenile myelomonocytic leukemia (JMML). NS3 inheritance is autosomal dominant.<ref>PMID:16773572</ref> <ref>PMID:16474405</ref> <ref>PMID:17468812</ref> <ref>PMID:17056636</ref> <ref>PMID:19396835</ref> <ref>PMID:20949621</ref>   Defects in KRAS are a cause of gastric cancer (GASC) [MIM:[http://omim.org/entry/613659 613659]]; also called gastric cancer intestinal or stomach cancer. Gastric cancer is a malignant disease which starts in the stomach, can spread to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs. It also can metastasize to other parts of the body. The term gastric cancer or gastric carcinoma refers to adenocarcinoma of the stomach that accounts for most of all gastric malignant tumors. Two main histologic types are recognized, diffuse type and intestinal type carcinomas. Diffuse tumors are poorly differentiated infiltrating lesions, resulting in thickening of the stomach. In contrast, intestinal tumors are usually exophytic, often ulcerating, and associated with intestinal metaplasia of the stomach, most often observed in sporadic disease.<ref>PMID:3034404</ref> <ref>PMID:7773929</ref> <ref>PMID:14534542</ref>   Note=Defects in KRAS are a cause of pylocytic astrocytoma (PA). Pylocytic astrocytomas are neoplasms of the brain and spinal cord derived from glial cells which vary from histologically benign forms to highly anaplastic and malignant tumors.<ref>PMID:8439212</ref>   Defects in KRAS are a cause of cardiofaciocutaneous syndrome (CFC syndrome) [MIM:[http://omim.org/entry/115150 115150]]; also known as cardio-facio-cutaneous syndrome. CFC syndrome is characterized by a distinctive facial appearance, heart defects and mental retardation. Heart defects include pulmonic stenosis, atrial septal defects and hypertrophic cardiomyopathy. Some affected individuals present with ectodermal abnormalities such as sparse, friable hair, hyperkeratotic skin lesions and a generalized ichthyosis-like condition. Typical facial features are similar to Noonan syndrome. They include high forehead with bitemporal constriction, hypoplastic supraorbital ridges, downslanting palpebral fissures, a depressed nasal bridge, and posteriorly angulated ears with prominent helices. The inheritance of CFC syndrome is autosomal dominant.  Note=KRAS mutations are involved in cancer development. 
== Function ==
[[http://www.uniprot.org/uniprot/RASK_HUMAN RASK_HUMAN]] Ras proteins bind GDP/GTP and possess intrinsic GTPase activity. 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Targeting specific protein-protein interactions (PPIs) is an attractive concept for drug development, but hard to implement since intracellular antibodies do not penetrate cells and most small-molecule drugs are considered unsuitable for PPI inhibition. A potential solution to these problems is to select intracellular antibody fragments to block PPIs, use these antibody fragments for target validation in disease models and finally derive small molecules overlapping the antibody-binding site. Here, we explore this strategy using an anti-mutant RAS antibody fragment as a competitor in a small-molecule library screen for identifying RAS-binding compounds. The initial hits are optimized by structure-based design, resulting in potent RAS-binding compounds that interact with RAS inside the cells, prevent RAS-effector interactions and inhibit endogenous RAS-dependent signalling. Our results may aid RAS-dependent cancer drug development and demonstrate a general concept for developing small compounds to replace intracellular antibody fragments, enabling rational drug development to target validated PPIs.

Small molecule inhibitors of RAS-effector protein interactions derived using an intracellular antibody fragment.,Quevedo CE, Cruz-Migoni A, Bery N, Miller A, Tanaka T, Petch D, Bataille CJR, Lee LYW, Fallon PS, Tulmin H, Ehebauer MT, Fernandez-Fuentes N, Russell AJ, Carr SB, Phillips SEV, Rabbitts TH Nat Commun. 2018 Aug 9;9(1):3169. doi: 10.1038/s41467-018-05707-2. PMID:30093669<ref>PMID:30093669</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5ocg" style="background-color:#fffaf0;"></div>

==See Also==
*[[GTPase KRas 3D structures|GTPase KRas 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Cruz-Migoni, A]]
[[Category: Ehebauer, M T]]
[[Category: Phillips, S E.V]]
[[Category: Quevedo, C E]]
[[Category: Rabbitts, T H]]
[[Category: Domain antibody]]
[[Category: Drug fragment screening]]
[[Category: Hydrolase]]
[[Category: Small molecule]]