研究人员在10月在线出版的《自然—化学生物学》期刊上报告说,他们发明了一种探讨蛋白质变性的新化学生物学工具。这些新发明将为许多重要的生物化学信号的生物学功能的确定提供一种框架。
蛋白质通常是由特定的氨基酸编码,并被送入细胞中不同的位置。作为选择,多种小化学基团可用于蛋白质的修饰,并让它们在细胞内移动。通过将一种特别的氨基酸导入细胞内的蛋白质链中,看它对Pho4蛋白质的影响,Peter G. Schultz和同事研究了蛋白质变性的过程。
这种特别的氨基酸很像构成蛋白质的丝氨酸,只是它被一个大基团包围,但这种大基团在光的照射下会被移走。一旦暴露在光线中,通过一种正常的细胞过程,丝氨酸就会被一个磷酸基团磷酸化或修饰。Schultz和同事发现,在蛋白质序列中,每5个丝氨酸中就有1个在控制蛋白质是否出入细胞核中发挥着特别重要的作用。这一新技术为监测磷酸化的功能提供了一种强有力的新方法。(科学时报)
原始出处:
Nature Chemical Biology
Published online: 28 October 2007 | doi:10.1038/nchembio.2007.44
Control of protein phosphorylation with a genetically encoded photocaged amino acid
Edward A Lemke1,3, Daniel Summerer1,3, Bernhard H Geierstanger2, Scott M Brittain2 & Peter G Schultz1,2
We genetically encoded the photocaged amino acid 4,5-dimethoxy-2-nitrobenzylserine (DMNB-Ser, 1) in Saccharomyces cerevisiae in response to the amber nonsense codon TAG. This amino acid was converted to serine in living cells by irradiation with relatively low-energy blue light and was used to noninvasively photoactivate phosphorylation of the transcription factor Pho4, which controls the cellular response to inorganic phosphate1. When substituted at phosphoserine sites that control nuclear export of Pho4, 1 blocks phosphorylation and subsequent export by the receptor Msn5 (ref. 2). We triggered phosphorylation of individual serine residues with a visible laser pulse and monitored nuclear export of Pho4-GFP fusion constructs in real time. We observed distinct export kinetics for differentially phosphorylated Pho4 mutants, which demonstrates dynamic regulation of Pho4 function. This methodology should also facilitate the analysis of other cellular processes involving free serine residues, including catalysis, biomolecular recognition and ion transport.
Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road SR202, La Jolla, California 92037, USA.
Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121-1125, USA.
These authors contributed equally to this work.
Correspondence to: Peter G Schultz1,2 Email: schultz@scripps.edu