Lin S, Cotter R J, Woods A S
Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.
Proteins. 1998;Suppl 2:12-21.
DNA-histone interaction facilitates packaging of huge amounts of DNA in the confined space of the nucleus. The importance of this interaction underscores the need for new analytical techniques to acquire a better understanding of nuclear dynamics. Electrospray-ionization mass spectrometry made it possible to investigate non-covalently-bound biopolymers. We are enlarging the scope of available analytical tools by studying non-covalent interaction between single and double stranded DNA and peptides with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The interaction is an ionic one, between the negatively charged sugar-phosphate backbone of single stranded DNA and positively charged side chains of Arg- and Lys-rich peptides as demonstrated by Vertes' group with the dipeptides Arg-Lys and His-His. We replicated Lecchi and Pannell's work, which showed that double stranded DNA could be seen by MALDI using 6-aza-2-thiothymine (ATT) as matrix. We tried various peptides and found that as was demonstrated in DNA-histone interaction, a certain ratio and arrangement of basic residues was needed in order to generate ionic binding between DNA and peptide. We tested various single and double stranded DNA with the peptide of choice, and found that other variables such as pH value of solution, ionic strength, and matrix system did play a role.
DNA与组蛋白的相互作用有助于在细胞核的有限空间内包装大量DNA。这种相互作用的重要性凸显了需要新的分析技术来更好地理解核动力学。电喷雾电离质谱法使研究非共价结合的生物聚合物成为可能。我们通过用基质辅助激光解吸/电离（MALDI）质谱法研究单链和双链DNA与肽之间的非共价相互作用，扩大了可用分析工具的范围。这种相互作用是离子性的，发生在单链DNA带负电荷的糖磷酸主链与富含精氨酸和赖氨酸的肽的带正电荷的侧链之间，正如韦尔特斯团队用二肽精氨酸-赖氨酸和组氨酸-组氨酸所证明的那样。我们重复了莱基和潘内尔的工作，他们的工作表明，使用6-氮杂-2-硫胸腺嘧啶（ATT）作为基质，MALDI可以检测到双链DNA。我们尝试了各种肽，发现正如在DNA与组蛋白的相互作用中所证明的那样，为了在DNA和肽之间产生离子结合，需要一定比例和排列的碱性残基。我们用选定的肽测试了各种单链和双链DNA，发现溶液的pH值、离子强度和基质系统等其他变量确实起到了作用。
