HISTONE DEACETYLASE 8

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 金属依赖性组蛋白去乙酰化酶（HDAC）需要Zn ~（2+）或Fe ~（2+）来调节真核细胞中组蛋白和其他蛋白质中赖氨酸残基的乙酰化。 HDAC 8同工酶可能是I类HDAC家族的典型成员，代表了理解该酶家族中结构-活性关系的范例。 在这里，我们报告了HDAC 8复合物的结构与阿司他丁A和3-（1-甲基-4-苯乙酰基-1H-2-吡咯基）-N-羟基-2-丙烯酰胺（APHA）在一个新的晶体形式。 的APHA复合物的结构表明，异羟肟酸C=O组不协调的锌2+与有利的几何形状，也许是由于其扩展的限制？系统，而是接受来自Y306的氢键。 此外，由于APHA仅与该复合物的不对称单元中的3个蛋白质分子中的2个结合，因此第三单体的结构代表HDAC 8在未配体状态下的第一结构。 未配体和配体结构的比较说明了L2环中可能伴随底物结合和催化的配体诱导的构象变化。 此外，这些结构，连同D101 N、D101 E、D101 A和D101 L变体的结构，沿着支持D101对L2环的功能至关重要的提议。 然而，D101的氨基酸取代也可引发Y111和W141的构象变化，从而干扰底物结合位点。 我们正在继续努力获得D101 E突变体的更高分辨率数据，并努力探索HDAC 8酶的钾结合位点。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Metal-dependent histone deacetylases (HDACs) require Zn2+ or Fe2+ to regulate the acetylation of lysine residues in histones and other proteins in eukaryotic cells. The HDAC8 isozyme is perhaps the archetypical member of the class I HDAC family and represents the paradigm for understanding structure-activity relationships in this enzyme family. Here, we report the structures of HDAC8 complexes with trichostatin A and 3-(1-methyl-4-phenylacetyl-1H-2-pyrrolyl)-N-hydroxy-2-propenamide (APHA) in a new crystal form. The structure of the APHA complex reveals that the hydroxamate C=O group does not coordinate to Zn2+ with favorable geometry, perhaps due to the constraints of its extended ? system, but instead accepts a hydrogen bond from Y306. Additionally, since APHA binds to only 2 of the 3 protein molecules in the asymmetric unit of this complex, the structure of the third monomer represents the first structure of HDAC8 in the unliganded state. Comparison of unliganded and liganded structures illustrates ligand-induced conformational changes in the L2 loop that likely accompany substrate binding and catalysis. Furthermore, these structures, along with those of the D101N, D101E, D101A, and D101L variants, support the proposal that D101 is critical for the function of the L2 loop. However, amino acid substitutions for D101 can also trigger conformational changes of Y111 and W141 that perturb the substrate binding site. We are continuing to work on getting higher resolution data for the D101E mutant, and working to explore potassium binding sites with the HDAC8 enzyme.