Sun Yiwen, Liu Chuan, Tang Wenzhu, Zhang Dawei
Department of Biological Sciences, School of Biological Engineering, Dalian Polytechnic University, Dalian 116034, People's Republic of China.
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, People's Republic of China.
ACS Omega. 2020 Nov 2;5(45):29140-29146. doi: 10.1021/acsomega.0c03867. eCollection 2020 Nov 17.
Guanosine monophosphate, the precursor for riboflavin biosynthesis, can be converted to or generated from other purine compounds in purine metabolic networks. In this study, genes in these networks were manipulated in a riboflavin producer, R, to test their contribution to riboflavin biosynthesis. Knocking out adenine phosphoribosyltransferase (), xanthine phosphoribosyltransferase (), and adenine deaminase () increased the riboflavin production by 14.02, 6.78, and 41.50%, respectively, while other deletions in the salvage pathway, interconversion pathway, and nucleoside decomposition genes have no positive effects. The enhancement of riboflavin production in and deletion mutants is dependent on the purine biosynthesis regulator PurR. Repression of ribonucleotide reductases (RNRs) led to a 13.12% increase of riboflavin production, which also increased in two RNR regulator mutants PerR and NrdR by 37.52 and 8.09%, respectively. The generation of deoxyribonucleoside competed for precursors with riboflavin biosynthesis, while other pathways do not contribute to the supply of precursors; nevertheless, they have regulatory effects.
鸟苷单磷酸是核黄素生物合成的前体，在嘌呤代谢网络中可由其他嘌呤化合物转化而来或生成其他嘌呤化合物。在本研究中，在核黄素产生菌R中对这些网络中的基因进行操作，以测试它们对核黄素生物合成的贡献。敲除腺嘌呤磷酸核糖转移酶、黄嘌呤磷酸核糖转移酶和腺嘌呤脱氨酶分别使核黄素产量提高了14.02%、6.78%和41.50%，而补救途径、相互转化途径和核苷分解基因中的其他缺失则没有积极作用。和缺失突变体中核黄素产量的提高依赖于嘌呤生物合成调节因子PurR。抑制核糖核苷酸还原酶使核黄素产量提高了13.12%，在两个核糖核苷酸还原酶调节突变体PerR和NrdR中分别提高了37.52%和8.09%。脱氧核糖核苷的生成与核黄素生物合成竞争前体，而其他途径对前体供应没有贡献；然而，它们具有调节作用。
