Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA.
Biochemistry. 2011 Sep 27;50(38):8107-16. doi: 10.1021/bi200822c. Epub 2011 Aug 30.
The molecular mechanism for the displacement of HMGA1 proteins from DNA is integral to disrupting their cellular function, which is linked to many metastatic cancers. Chemical shift and NOESY NMR experiments provide structural evidence for the displacement of an AT hook peptide (DNA binding motif of HMGA1 proteins) by both monomeric and dimeric distamycin. However, the displaced AT hook alters distamycin binding by weakening the distamycin:DNA complex, while slowing monomeric distamycin dissociation when AT hook is in excess. The central role of the AT hook was evaluated by monitoring full-length HMGA1a protein binding using fluorescence anisotropy. HMGA1a was effectively displaced by distamycin, but the cooperative binding exhibited by distamycin was eliminated by displaced HMGA1a. Additionally, these studies indicate that HMGA1a is displaced from the DNA by 1 equiv of distamycin, suggesting the ability to develop therapeutics that take advantage of the positively cooperative nature of HMGA1a binding.
HMGA1 蛋白从 DNA 上的置换的分子机制对于破坏其细胞功能至关重要，而细胞功能与许多转移性癌症有关。化学位移和 NOESY NMR 实验为单体和二聚体放线菌素通过置换 AT 钩肽（HMGA1 蛋白的 DNA 结合基序）提供了结构证据。然而，被置换的 AT 钩通过削弱放线菌素：DNA 复合物来改变放线菌素的结合，而当 AT 钩过量时，会减缓单体放线菌素的解离。通过使用荧光各向异性监测全长 HMGA1a 蛋白的结合，评估了 AT 钩的核心作用。放线菌素有效地置换了 HMGA1a，但被置换的 HMGA1a 消除了放线菌素的协同结合。此外，这些研究表明，HMGA1a 被 1 当量的放线菌素从 DNA 上置换，这表明可以开发利用 HMGA1a 结合的正协同性质的治疗药物。
