Allelic Analyses of the Arabidopsis YUC1 Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

作     者：Xianhui Hou Sainan Liu Florencia Pierri Xinhua Dai Li-Jia Qu Yunde Zhao 

作者机构：National Laboratory for Protein Engineering and Plant Genetic Engineering Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology College of Life Sciences Peking University Beijing 100871 China Section of Cell and Developmental Biology University of California at San Diego La Jolla California 92093-0116 USA 

出 版 物：《Journal of Integrative Plant Biology》 (植物学报（英文版）)

年 卷 期：2011年第53卷第1期

页      面：54-62页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 09[农学] 071007[理学-遗传学] 0901[农学-作物学] 090102[农学-作物遗传育种] 

基　　金：supported by the National Natural Science Foundation of China (No. 30628012 to Y.Z and 30625002 to L.-J.Q) National Institutes of Health (R01GM68631 to Y.Z.) supported by a scholarship from the China Scholarship Council 

主　　题：ARABIDOPSIS FLAVINS MONOOXYGENASES PLANT enzymes PHOTOSYNTHESIS NAD (Coenzyme) PLANT mutation NUCLEOTIDES AUXIN 

摘      要：Flavin monooxygenases （FMOs） play critical roles in plant growth and development by synthesizing auxin and other signaling molecules. However, the structure and function relationship within plant FMOs is not understood. Here we defined the important residues and domains of the Arabidopsis YUC1 FMO, a key enzyme in auxin biosynthesis. We previously showed that simultaneous inactivation of YUC1 and its homologue YUC4 caused severe defects in vascular and floral development. We mutagenized the yuc4 mutant and screened for mutants with phenotypes similar to those of yucl yuc4 double mutants. Among the isolated mutants, five of them contained mutations in the YUC1 gene. Interestingly, the mutations identified in the new yucl alleles were concentrated in the two GXGXXG motifs that are highly conserved among the plant FMOs. One such motif presumably binds to flavin adenine dinucleotide （FAD） cofactor and the other binds to nicotinamide adenine dinucleotide phosphate （NADPH）. We also identified the Ser139 to Phe conversion in yucl, a mutation that is located between the two nucleotide-binding sites. By analyzing a series of yucl mutants, we identified key residues and motifs essential for the functions of YUC1 FMO.