Lin Yushan, Chen Min, Jiang Wei, Zhang Likui, Shen Li, Bai Yanchao
College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
The Key Laboratory of the Jiangsu Higher Education Institutions for Integrated Traditional Chinese and Western Medicine in Senile Diseases Control (Yangzhou University) & Institute of Translational Medicine, School of Medicine, Yangzhou University, Yangzhou 225001, China.
J Agric Food Chem. 2025 Jan 29;73(4):2393-2403. doi: 10.1021/acs.jafc.4c08894. Epub 2025 Jan 18.
Phytoene synthase (PSY) is one of key enzymes in carotenogenesis that catalyze two molecules of geranylgeranyl diphosphate to produce phytoene. PSY is widespread in bacteria, archaea, and eukaryotes. Currently, functional role and catalytic mechanism of archaeal PSY homologues have not been fully clarified due to the limited reports. Herein, we identified a rate-limiting role of the PSY from the halophilic euryarchaeon (HVO-PSY) in bacterioruberin biosynthesis and dissected the roles of its seven conserved residues. Compared with the parental strain, the recombinant HVO-PSY strain had the increased bacterioruberin yields, confirming that HVO-PSY is a rate-limiting enzyme in bacterioruberin biosynthesis in . Additionally, we optimized the culture condition for bacterioruberin biosynthesis in the recombinant strain: 150 g/L NaCl, 45 °C, and pH 6.5-7.5. Mutational data demonstrate that residues D47, D51, D110, D168, D172, and R178 of HVO-PSY are essential for catalysis since these recombinant mutant strains harboring these mutations in the enzyme had the reduced bacterioruberin yields relative to the recombinant wild-type strain. Overall, our findings have verified the rate-limiting role of HVO-PSY in bacterioruberin biosynthesis in and clarified the essential roles of its conserved residues D47, D51, D110, D168, D172, and R178 in catalysis.
八氢番茄红素合酶（PSY）是类胡萝卜素生成过程中的关键酶之一，它催化两分子的香叶基香叶基二磷酸生成八氢番茄红素。PSY广泛存在于细菌、古菌和真核生物中。目前，由于相关报道有限，古菌PSY同源物的功能作用和催化机制尚未完全阐明。在此，我们确定了嗜盐广古菌的PSY（HVO-PSY）在细菌红素生物合成中的限速作用，并剖析了其七个保守残基的作用。与亲本菌株相比，重组HVO-PSY菌株的细菌红素产量增加，证实HVO-PSY是细菌红素生物合成中的限速酶。此外，我们优化了重组菌株中细菌红素生物合成的培养条件：150 g/L NaCl、45℃和pH 6.5 - 7.5。突变数据表明，HVO-PSY的残基D47、D51、D110、D168、D172和R178对催化至关重要，因为相对于重组野生型菌株，这些在酶中携带这些突变的重组突变菌株的细菌红素产量降低。总体而言，我们的研究结果证实了HVO-PSY在细菌红素生物合成中的限速作用，并阐明了其保守残基D47、D51、D110、D168、D172和R178在催化中的重要作用。
