Borthakur D, Haselkorn R
Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637.
Plant Mol Biol. 1989 Oct;13(4):427-39. doi: 10.1007/BF00015555.
The 33 kDa extrinsic polypeptide of photosystem II, also known as the manganese-stabilizing polypeptide (MSP), is located on the lumen side of the thylakoid and is involved in water oxidation. The gene for MSP, designated woxA, has been cloned from the nitrogen-fixing filamentous cyanobacterium Anabaena and sequenced. The woxA open reading frame was found to be 819 bp. The deduced amino acid sequence was 63% and 59% homologous with that of Synechococcus and Synechocystis, respectively, and 44% conserved when compared to the MSP of spinach or pea. Two cysteine residues at positions 48 and 73 were found to be conserved in cyanobacteria and plants. The first 29 amino acids are hydrophobic and may represent the transit peptide. woxA: :phoA translational fusion products, in which the body of Escherichia coli alkaline phosphatase was fused to the amino terminal portion of woxA between residues 35 and 130, yielded active alkaline phosphatase in E. coli. Thus the transit peptide of woxA functions in E. coli to transport phosphatase across the cytoplasmic membrane. S1 mapping and primer extension experiments showed that the woxA transcription initiation site is located 220 bp upstream from the translational start. The woxA promoter has some resemblance to the E. coli consensus and other known Anabaena vegetative cell promoters.
光系统II的33 kDa外在多肽，也称为锰稳定多肽（MSP），位于类囊体的腔侧，参与水的氧化。已从固氮丝状蓝藻鱼腥藻中克隆并测序了MSP的基因，命名为woxA。发现woxA开放阅读框为819 bp。推导的氨基酸序列与聚球藻属和集胞藻属的序列分别具有63%和59%的同源性，与菠菜或豌豆的MSP相比，有44%的保守性。发现在位置48和73处的两个半胱氨酸残基在蓝细菌和植物中是保守的。前29个氨基酸是疏水的，可能代表转运肽。woxA::phoA翻译融合产物（其中大肠杆菌碱性磷酸酶的主体与woxA残基35和130之间的氨基末端部分融合）在大肠杆菌中产生了活性碱性磷酸酶。因此，woxA的转运肽在大肠杆菌中起作用，将磷酸酶转运穿过细胞质膜。S1图谱分析和引物延伸实验表明，woxA转录起始位点位于翻译起始上游220 bp处。woxA启动子与大肠杆菌共有序列和其他已知的鱼腥藻营养细胞启动子有一些相似之处。
