Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Montañana, Zaragoza, Spain.
BMC Evol Biol. 2010 Oct 18;10:311. doi: 10.1186/1471-2148-10-311.
Flavin adenine dinucleotide synthetases (FADSs) - a group of bifunctional enzymes that carry out the dual functions of riboflavin phosphorylation to produce flavin mononucleotide (FMN) and its subsequent adenylation to generate FAD in most prokaryotes - were studied in plants in terms of sequence, structure and evolutionary history.
Using a variety of bioinformatics methods we have found that FADS enzymes localized to the chloroplasts, which we term as plant-like FADS proteins, are distributed across a variety of green plant lineages and constitute a divergent protein family clearly of cyanobacterial origin. The C-terminal module of these enzymes does not contain the typical riboflavin kinase active site sequence, while the N-terminal module is broadly conserved. These results agree with a previous work reported by Sandoval et al. in 2008. Furthermore, our observations and preliminary experimental results indicate that the C-terminus of plant-like FADS proteins may contain a catalytic activity, but different to that of their prokaryotic counterparts. In fact, homology models predict that plant-specific conserved residues constitute a distinct active site in the C-terminus.
A structure-based sequence alignment and an in-depth evolutionary survey of FADS proteins, thought to be crucial in plant metabolism, are reported, which will be essential for the correct annotation of plant genomes and further structural and functional studies. This work is a contribution to our understanding of the evolutionary history of plant-like FADS enzymes, which constitute a new family of FADS proteins whose C-terminal module might be involved in a distinct catalytic activity.
黄素腺嘌呤二核苷酸合成酶（FADSs）-一组双功能酶，在大多数原核生物中执行核糖醇磷酸化产生黄素单核苷酸（FMN）及其随后的腺嘌呤化生成黄素腺嘌呤二核苷酸（FAD）的双重功能-在植物中从序列、结构和进化历史方面进行了研究。
使用各种生物信息学方法，我们发现定位于叶绿体的 FADS 酶，我们称之为植物样 FADS 蛋白，分布在各种绿色植物谱系中，并构成一个明显源自蓝细菌的发散蛋白家族。这些酶的 C 末端模块不包含典型的核黄素激酶活性位点序列，而 N 末端模块广泛保守。这些结果与 2008 年 Sandoval 等人之前的工作一致。此外，我们的观察和初步实验结果表明，植物样 FADS 蛋白的 C 末端可能含有催化活性，但与原核对应物的不同。事实上，同源建模预测植物特异性保守残基在 C 末端构成一个独特的活性位点。
报告了对黄素腺嘌呤二核苷酸合成酶（FADSs）的基于结构的序列比对和深入进化调查，这些酶被认为对植物代谢至关重要，这对于正确注释植物基因组以及进一步的结构和功能研究至关重要。这项工作有助于我们理解植物样 FADS 酶的进化历史，这些酶构成了一个新的 FADS 蛋白家族，其 C 末端模块可能参与独特的催化活性。
