2j6w
R164N mutant of the RUNX1 Runt domain
Structural highlights
DiseaseRUNX1_MOUSE Note=Mice with an Runx1 lacking the DNA-binding region are found to die between embryonic days 11.5 to 12.5 due to hemorrhaging in the central nervous system. This hemorrhaging is preceded by necrosis and hematopoiesis is blocked. FunctionRUNX1_MOUSE CBF binds to the core site, 5'-PYGPYGGT-3', of a number of enhancers and promoters, including murine leukemia virus, polyomavirus enhancer, T-cell receptor enhancers, LCK, IL-3 and GM-CSF promoters. Essential for the development of normal hematopoiesis. Isoform 4 shows higher binding activities for target genes and binds TCR-beta-E2 and RAG-1 target site with threefold higher affinity than other isoforms. It is less effective in the context of neutrophil terminal differentiation. Acts synergistically with ELF4 to transactivate the IL-3 promoter and with ELF2 to transactivate the BLK promoter. Inhibits KAT6B-dependent transcriptional activation (By similarity).[1] [2] 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 Runt domain is the DNA binding domain of the core binding factor (CBF) Runx subunits. The CBFs are transcription factors that play critical roles in hematopoiesis, bone, and neuron development in mammals. A common non-DNA binding CBFbeta subunit heterodimerizes with the Runt domain of the Runx proteins and allosterically regulates its affinity for DNA. Previous NMR dynamics studies suggested a model whereby CBFbeta allosterically regulates DNA binding by quenching conformational exchange in the Runt domain, particularly in the S-switch region and the betaE'-F loop. We sought to test this model, and to this end introduced all possible single amino acid substitutions into the S-switch region and the betaE'-F loop, and screened for mutations that enhanced DNA-binding. We demonstrate that one Runt domain mutant, R164N, binds both DNA and CBFbeta with higher affinity, but it is less sensitive to allosteric regulation by CBFbeta. Analysis of NMR relaxation data shows that the chemical exchange exhibited by the wild-type Runt domain is largely quenched by the R164N substitution. These data support a model in which the dynamic behavior of a network of residues connecting the CBFbeta and DNA binding sites on the Runt domain plays a critical role in the mechanism of allosteric regulation. This study provides an important functional link between dynamic behavior and protein allosteric function, consistent with results on other allosterically regulated proteins. A mutation in the S-switch region of the Runt domain alters the dynamics of an allosteric network responsible for CBFbeta regulation.,Li Z, Lukasik SM, Liu Y, Grembecka J, Bielnicka I, Bushweller JH, Speck NA J Mol Biol. 2006 Dec 15;364(5):1073-83. Epub 2006 Oct 4. PMID:17059830[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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