专肽生物_定制多肽合成服务_多肽合成定制服务_多肽合成厂家_多肽合成公司

"Histone H3 (1-20) K4Me2 is derived from Histone 3 (H3), which is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core. H4 and H3 are highly conserved and perform roles in binding to segments of DNA which enter and leave the nucleosome and in chromatin formation. Like the other core histone, H3 has a globular domain and a flexible N-terminal domain, histone tail which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination. Due to histones containing many lysine and arginine residues, they have a positive net charge which interacts electrostatically with the negatively charged phosphate groups in DNA. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone-modifying enzymes which target histone proteins. Both processes change the positioning of the nucleosome, allowing the DNA to be either available to the transcription machinery or inaccessible.Histone tails can undergo multiple modifications, including acetylation, methylation, ubiquitylation and sumoylation.\xa0 The modification pattern is believed to alter chromatin function/structure. Histone H3 (1-20) K4Me2-GG-Lys(5-FAM) lysine 4 has been dimethylated, has a C-terminal GGK linker labelled with 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag. This peptide also has an uncharged C-terminal amide. H3 (1-20) K4Me2 has been investigated to understand its effect on epigenetic regulation through NMR with histone readers such as zinc finger domains. Histone H3 (1-20) K4Me2-GG-Lys(5-FAM) can be used to study the function of this pattern on chromatin availability and histone effectors via crystallisation, pull-down assays and protein blots."

FAM标记说明:
Carboxyfluorescein (FAM) is fluorophor with an excitation at 492 nm ▉ and emission of 517 nm ▉. Donors like FAM and 5FAM are often paired together with acceptors (CPQ2) for FRET experiments.

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甲基化修饰多肽
       也叫甲基化标记多肽，甲基化修饰是在其他常见的翻译后修饰（PTMs）中生物和物理化学特性方面非常突出的一种修饰手段。几乎参与细胞所有的生命活动过程，发挥着重要的调控作用，蛋白质在甲基转移酶的催化下将甲基转移至特定的氨基酸残基上共价结合的过程。甲基化是一种可逆的修饰过程，由去甲基化酶催化去甲基化作用。可以发生在20个常见氨基酸残基中的至少9个（Met, Cys, Lys, Arg, His, Gln, Asn, Glu and Asp）氨基酸中，而最常见甲基化/去甲基化主要发生在赖氨酸（Lys）和精氨酸（Arg）侧链上，几乎参与生物所有的生命活动过程，如调节细胞功能，如转录、细胞分裂和细胞分化。甲基化修饰能够发生在不同的氨基酸位点，或是在同一个氨基酸位点产生不止一个甲基化修饰。
       研究发现，常见甲基化／去甲基化作用的氨基酸主要是赖氨酸（Lys）和精氨酸（Arg）研究表明，组蛋白赖氨酸甲基化修饰执行着多种生物学功能，如干细胞的维持和分化、Ｘ染色体失活、转录调节和ＤＮＡ损伤反应等，主要是影响染色质浓缩，抑制基因表达。组蛋白精氨酸甲基化在基因转录调控中发挥着重要作用，并能影响细胞的多种生理过程，包括DNA修复、信号转导、细胞发育及癌症发生等因此专肽生物特地开发甲基化修饰多肽技术，为科学家在蛋白质翻译后修饰（PTMS）的研究中提供帮助。

甲基化修饰(Me1，Me2，Me3)

       采用高品质的Fmoc-Lys(Me,Boc)-OH、 Fmoc-Lys(Me2)-OH、Fmoc-Lys(Me3)-OH.HCL、Fmoc-Arg(Me,Pbf)-OH 、Fmoc-Arg(me)2-OH.HCl(asymmetrical) 、Fmoc-Arg(me)2-OH.HCl(symmetrical) 等原料，采用Fmoc固相合成工艺合成，得到Lys甲基化，Arg甲基化标记的多肽，使用HPLC 对产物进行纯化。最终产品提供相应的质谱图，纯度分析的HPLC 色谱图。