Urabe Hiroaki, Ogawara Hiroshi, Motojima Kiyoto
a Department of Biochemistry , Meiji Pharmaceutical University , Kiyose , Japan.
Biosci Biotechnol Biochem. 2015;79(5):855-62. doi: 10.1080/09168451.2014.996204. Epub 2015 Jan 3.
We identified and characterized a new eukaryotic-type protein kinase (PkaE) from Streptomyces coelicolor A3 (2) M145. PkaE, consisting of 510 amino acid residues, is a cytoplasmic protein kinase and contains the catalytic domain of eukaryotic protein kinases in the N-terminal region. Recombinant PkaE was found to be autophosphorylated at threonine residues only. The disruption of chromosomal pkaE resulted in the overproduction of the actinorhodin-related blue pigment antibiotics. pkaE was expressed during the late growth phase in S. coelicolor A3 (2) M145, which corresponded to the production time of blue pigments. This result indicated that PkaE acts as a negative regulator for production of the secondary metabolites. In addition, PkaE was able to phosphorylate KbpA, a regulator involved in the AfsK-AfsR regulatory pathway.
我们从天蓝色链霉菌A3（2）M145中鉴定并表征了一种新的真核型蛋白激酶（PkaE）。PkaE由510个氨基酸残基组成，是一种细胞质蛋白激酶，在N端区域含有真核蛋白激酶的催化结构域。发现重组PkaE仅在苏氨酸残基处发生自磷酸化。染色体pkaE的破坏导致放线紫红素相关蓝色色素抗生素的过量产生。pkaE在天蓝色链霉菌A3（2）M145的生长后期表达，这与蓝色色素的产生时间相对应。该结果表明PkaE作为次级代谢产物产生的负调节因子。此外，PkaE能够磷酸化KbpA，KbpA是AfsK - AfsR调节途径中的一种调节因子。
