Structure and Function of a C-C Bond Cleaving Oxygenase in Atypical Angucycline Biosynthesis----中国科学院微生物研究所

科研成果

论文题目:	Structure and Function of a C-C Bond Cleaving Oxygenase in Atypical Angucycline Biosynthesis
作者:	Pan Guohui , Gao Xiaoqin , Fan Keqiang , Liu Junlin , Meng Bing , Gao Jinmin , Wang Bin , Zhang Chaobo , Han Hui , Ai Guomin , Chen Yihua , Wu Dong, Liu Zhi-Jie, and Yang Keqian*.
联系作者:
刊物名称:	Acs Chemical Biology
期:
卷:	12
页:	142-152
年份:	2017
影响因子:	5.176
论文下载:	http://pubs.acs.org/doi/abs/10.1021/acschembio.6b00621
摘要:	C-C bond ring cleaving oxygenases represent a unique family of enzymes involved in the B ring cleavage reaction only observed in atypical angucycline biosynthesis. B ring cleavage is the key reaction leading to dramatic divergence in the final structures of atypical angucyclines. Here, we present the crystal structure of AlpJ, the first structure of this family of enzymes. AlpJ has been verified as the enzyme catalyzing C-C bond cleavage in kinamycin biosynthesis. The crystal structure of the AlpJ monomer resembles the dimeric structure of ferredoxin-like proteins. The N- and C-terminal halves of AlpJ are homologous, and both contain a putative hydrophobic substrate binding pocket in the "closed" and "open" conformations, respectively. Structural comparison of AlpJ with ActVA-Orf6 and protein ligand docking analysis suggest that the residues including Asn60, Trp64, and Trp181 are possibly involved in substrate recognition. Site-directed mutagenesis results supported our hypothesis, as mutation of these residues led to nearly a complete loss of the activity of AlpJ. Structural analysis also revealed that AlpJ possesses an intramolecular domain domain interface, where the residues His50 and Tyr178 form a hydrogen bond that probably stabilizes the three-dimensional structure of AlpJ. Site-directed mutagenesis showed that the two residues, His50 and Tyr178, were vital for the activity of AlpJ. Our findings shed light on the structure and catalytic mechanism of the AlpJ family of oxygenases, which presumably involves two active sites that might function in a cooperative manner.