人3'-磷酸腺苷5'-磷酸硫酸酯（PAPS）合酶：生物化学，分子生物学和遗传缺陷。,IUBMB Life

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人3'-磷酸腺苷5'-磷酸硫酸酯（PAPS）合酶：生物化学，分子生物学和遗传缺陷。
IUBMB Life ( IF 3.7 ) Pub Date : 2003-04-29 , DOI: 10.1080/1521654031000072148
K V Venkatachalam ₁

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3'-磷酸腺苷5'-磷酸硫酸酯（PAPS）合酶（PAPSS）催化PAPS的生物合成，该PAPS可用作所有磺基转移酶反应的通用磺酸盐供体化合物。PAPSS分两个连续步骤形成PAPS。首先，无机硫酸盐与ATP结合，形成三磷酸腺苷5'-磷酸硫酸盐（APS）和焦磷酸，然后在第二步中，APS与另一种ATP分子结合形成PAPS和由APS激酶结构域催化的ADP。双功能PAPSS1由NH2末端的APS激酶结构域（约1-260 aa）和COOH末端的ATP硫化酶结构域（约220-623 aa）组成。在人类中，有两种主要的亚型PAPSS1和PAPSS2。在脑和皮肤中，PAPSS1是主要表达的亚型，而在肝中，软骨和肾上腺中PAPSS2亚型的表达占主导地位，据称在其他各种组织中，亚型表达的比例也有所不同。推导的两个同工型的氨基酸序列揭示了PAPSS1和PAPSS2之间77％的同一性。另外，存在剪接变体PAPSS2b，其显着包含额外的五个氨基酸序列GMALP。从人类组织中，PAPSS1和一个剪接变体PAPSS2b已被分子克隆，过表达，纯化并已进行部分生化表征。PAPSS2b在变化的ATP浓度上表现出明显的差异，显示出S型响应，在1.4 mM ATP处为0.5 [v / Vmax]，而PAPSS1在0.25 mM ATP处呈现双曲响应，而0.5 [v / Vmax]。尽管情况如此，但比较PAPSS1和PAPSS2粗提物，底物ATP或硫酸盐未显示出动力学特性的显着差异，从而推测PAPSS2b中存在的额外GMALP五肽可能改变了动力学行为。APS中存在α-β-ATP水解的ATP结合位点，活性位点基序HxxH（425-428 aa）和APS中存在β-γ-水解酶基序GxxGxxK（59-65 aa）激酶结构域。两种同工型之间的基序高度保守。PAPSS1（约106 kB）和PAPSS2（约86.5 kB）的基因序列分析显示，共有12个外显子。在外显子2-11中，其大小高度保守，尽管内含子的大小差异很大。外显子1和12的大小各不相同，分别包含5'-UTR和3'-UTR。PAPSS1和PAPSS2不含推定的TATA盒和CCAAT盒。但是，PAPSS1和PAPSS2都拥有许多GC盒。从启动子分析，很明显PAPSS1和PAPSS2都是可诱导的，可能在不同的时间段受特定转录因子调控。PAPSS2的缺乏会导致骨软骨发育不良。骨软骨发育不良是遗传上异质的一组疾病，会影响骨骼发育，线性生长以及软骨和骨骼的维持。一个具有不同形式的隐性遗传性自发性肺结核，干met端发育异常（SEMD）的大型近交家族被定位到位于10q23-24染色体区域的PAPSS2亚型。据报道，PAPSS1位于染色体4q23缺陷中，并因此在高内皮小静脉中募集淋巴细胞。已经确定了PAPSS的几种单核苷酸多态性（SNP），

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Human 3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthase: biochemistry, molecular biology and genetic deficiency.

3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthase (PAPSS) catalyzes the biosynthesis of PAPS which serves as the universal sulfonate donor compound for all sulfotransferase reactions. PAPSS forms PAPS in two sequential steps. First inorganic sulfate combines with ATP to form adenosine 5'-phosphosulfate (APS) and pyrophosphate catalyzed by ATP sulfurylase domain and in the second step, APS combines with another molecule of ATP to form PAPS and ADP catalyzed by APS kinase domain. The bifunctional PAPSS1 is comprised of NH2-terminal APS kinase domain (approximately 1-260 aa), and a COOH-terminal ATP sulfurylase domain (approximately 220-623 aa). In humans there are two major isoforms PAPSS1 and PAPSS2. In brain and skin PAPSS1 is the major expressed isoform, whereas in liver, cartilage and adrenal glands PAPSS2 isoform expression predominates and in various other tissues the proportions of the isoform expressions is purported to vary. The deduced amino acid sequences of the two isoforms reveal 77% identity between PAPSS1 and PAPSS2. In addition there is a splice variant PAPSS2b which contains notably an extra five amino acid sequence GMALP. From human tissues PAPSS1 and a splice variant PAPSS2b has been molecularly cloned, overexpressed, purified and have been biochemically characterized partially. PAPSS2b exhibited an apparent difference towards varying ATP concentration showing a sigmoidal response, with a 0.5 [v/Vmax] at 1.4 mM ATP whereas PAPSS1 exhibited a hyperbolic response with a 0.5 [v/Vmax] at 0.25 mM ATP. Although this being the case, comparison of PAPSS1 and PAPSS2 crude extracts, did not show marked difference in the kinetic properties with either substrates ATP or sulfate leading to speculate that the extra GMALP pentapeptide present in PAPSS2b could be altering the kinetic behavior. The ATP binding sites of the alpha-beta-ATP hydrolysis, active site motif HxxH (425-428 aa) is present in the ATP sulfurylase domain and the beta-gamma-hydrolase motif GxxGxxK (59-65 aa) is present in the APS kinase domain. The motifs are highly conserved between both isoforms. Gene sequence analysis of PAPSS1 (approximately 106 kB) and PAPSS2 (approximately 86.5 kB), revealed a total of 12 exons. Among exons 2-11 the sizes are highly conserved, although intron sizes varied remarkably. Exons 1 and 12 varied in sizes, contained 5'-UTR and 3'-UTR respectively. PAPSS1 and PAPSS2 contained no putative TATA box and CCAAT box. However both PAPSS1 and PAPSS2 possessed many GC boxes. From promoter analysis, it is apparent that both PAPSS1 and PAPSS2 are inducible, perhaps at various time periods, regulated by specific transcription factors. The deficiency of PAPSS2 results in osteochondrodysplasias. Osteochondrodysplasias are genetically heterogeneous group of disorders that affects skeletal development, linear growth, and the maintenance of cartilage and bone. A large inbred family with a distinct form of recessively inherited, spondyloepimetaphyseal dysplasia (SEMD) was mapped to PAPSS2 isoform located in the chromosome region of 10q23-24. PAPSS1 located in the chromosome 4q23 deficiency and consequent effect in lymphocyte recruitment in High Endothelial Venules has been reported. Several single nucleotide polymorphism (SNP) of PAPSS has been identified, some of which are in the coding region (cSNPs), has been shown to have altered enzyme activity.

更新日期：2019-11-01

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