School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, Henan, China; School of Chemical Engineering and Food Science, Zhengzhou University of Technology, Zhengzhou 450044, Henan, China.
School of Chemical and Printing-Dyeing Engineering, Henan University of Engineering, Zhengzhou 450007, Henan, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Jun 5;294:122531. doi: 10.1016/j.saa.2023.122531. Epub 2023 Feb 22.
Various peptide drugs have entered the market with the development of molecular biology. Peptide drugs are used for treat diseases such as diabetes, breast cancer, and HIV infection. In this study, three nicotinamide-modified peptides were synthesized by modifying the N-terminus of BRCA1 (856-871, Y856R, K862Y, R866W) peptide with three nicotinic acid derivatives using solid-phase peptide synthesis. The results of calf thymus DNA (ctDNA) binding activity indicated that binding constants of BRCA1 (856-871, Y856R, K862Y, R866W) (P0) and three nicotinamide-modified peptides (P1, P2, and P3) to ctDNA were 1.89 × 10, 2.97 × 10, 7.61 × 10, and 8.09 × 10 L·mol, respectively. The binding affinity of the modified peptides was superior to that of BRCA1 (856-871, Y856R, K862Y, R866W). ΔH < 0 and ΔS < 0 indicated that van der Waals force and hydrogen bond contributed most to peptide-ctDNA binding. Results obtained by Circular dichroism (CD) indicated that peptide binding interaction led to conformational changes in ctDNA. Ultraviolet-visible (UV) spectroscopy, ethidium bromide (EB) competition experiments, DNA melting experiments, and viscosity measurements verified that peptides interacted with ctDNA via groove binding. Ionic strength experiments manifested that electrostatic binding was also involved in peptide-ctDNA binding.
随着分子生物学的发展，各种肽类药物已经进入市场。肽类药物用于治疗糖尿病、乳腺癌、艾滋病感染等疾病。在本研究中，通过固相肽合成，用三种烟酸衍生物修饰 BRCA1（856-871、Y856R、K862Y、R866W）肽的 N 端，合成了三种烟酰胺修饰肽。小牛胸腺 DNA（ctDNA）结合活性结果表明，BRCA1（856-871、Y856R、K862Y、R866W）（P0）和三种烟酰胺修饰肽（P1、P2 和 P3）与 ctDNA 的结合常数分别为 1.89×10、2.97×10、7.61×10 和 8.09×10 L·mol。修饰肽的结合亲和力优于 BRCA1（856-871、Y856R、K862Y、R866W）。ΔH<0 和 ΔS<0 表明范德华力和氢键对肽-DNA 结合的贡献最大。圆二色性（CD）结果表明，肽结合相互作用导致 ctDNA 构象发生变化。紫外可见（UV）光谱、溴化乙锭（EB）竞争实验、DNA 熔点实验和粘度测量验证了肽通过沟结合与 ctDNA 相互作用。离子强度实验表明静电结合也参与了肽-DNA 的结合。
