S-sulfocystein

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: S-sulfocystein
• 英文别名: (2R)-2-amino-3-sulfosulfanylpropanoate
• 化学式: C₃H₆NO₅S₂
• 分子量: 200.216
• InChiKey: NOKPBJYHPHHWAN-REOHCLBHSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  -4.1
• 重原子数：
  11
• 可旋转键数：
  3
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.67
• 拓扑面积：
  154
• 氢给体数：
  2
• 氢受体数：
  7

反应信息

• 作为反应物：
  描述：

  S-sulfocystein 在 thioredoxin reductase 、 Tris-HCl buffer 、 还原型辅酶II(NADPH)四钠盐 、 thioredoxin 作用下， 生成 L-半胱氨酸 、 alkaline earth salt of/the/ methylsulfuric acid
  参考文献：
  名称：

  Funane, Kazumi; Iwahashi, Hitoshi; Nakamura, Taro, Agricultural and Biological Chemistry, 1987, vol. 51, # 5, p. 1247 - 1256

  摘要：

  DOI：
• 作为产物：
  描述：

  (2S)-2-amino-3-[hydroxy(oxido)phosphoryl]oxypropanoate 、 dioxido-oxo-sulfanylidene-λ6-sulfane;hydron 生成 H3PO4 、 S-sulfocystein
  参考文献：
  名称：

  CysK2 from Mycobacterium tuberculosis Is an O -Phospho- l -Serine-Dependent S -Sulfocysteine Synthase

  摘要：

  摘要 结核分枝杆菌 依赖于半胱氨酸的生物合成，由半胱氨酸合成的还原硫化合物（如霉菌硫醇）是抵御巨噬细胞氧化应激的一线防御机制。两种生物合成途径 l -半胱氨酸的两种生物合成途径，每种途径都有自己特定的半胱氨酸合成酶（CysK1 和 CysM）。 结核杆菌 但该病原体中第三种假定的巯基酶 CysK2 的功能仍未确定。我们提出的生化和生物物理证据表明，CysK2 是一种巯基酶。 S -硫代半胱氨酸合成酶，利用 O -磷酸丝氨酸（OPS）和硫代硫酸盐作为底物。该酶通过一个氨基丙烯酸酯中心中间体进行合成，其机制与这个依赖于磷酸吡哆醛的酶家族的其他成员相似。与 OPS 的第一个半反应的表观二阶速率被确定为 k max / K s = (3.97 × 10 3 ) ± 619 M -1 s -1 与OPS特异性分枝杆菌半胱氨酸合成酶CysM的 k max / K s 的（1.34×10 3 ) ± 48.2.值得注意的是，CysK2 并不利用硫代羧化的 CysO 作为硫供体，而是接受硫代硫酸盐和硫化物作为供体底物。特异性常数 k cat / K m 硫代硫酸盐的 K m 是硫化物的 40 倍，这表明注释为 S -硫代半胱氨酸合成酶。因此，分枝杆菌的 CysK2 为半胱氨酸提供了第三种代谢途径，即直接使用硫化物作为供体或间接通过 S -硫代半胱氨酸。假设 S -硫代半胱氨酸还可以作为一种信号分子，在休眠期接触活性氧时触发病原体的氧化还原防御反应。

  DOI：

  10.1128/jb.01851-14

文献信息

• <i>Arabidopsis</i>  <i>S</i>-Sulfocysteine Synthase Activity Is Essential for Chloroplast Function and Long-Day Light-Dependent Redox Control
  作者：Maria Angeles Bermúdez、Maria Angeles Páez-Ochoa、Cecilia Gotor、Luis C. Romero

  DOI：10.1105/tpc.109.071985

  日期：2010.3.25

  In bacteria, the biosynthesis of Cys is accomplished by two enzymes that are encoded by the cysK and cysM genes. CysM is also able to use thiosulfate as a substrate to produce S-sulfocysteine. In plant cells, the biosynthesis of Cys occurs in the cytosol, mitochondria, and chloroplasts. Chloroplasts contain two O-acetylserine(thiol)lyase homologs, which are encoded by the OAS-B and CS26 genes in Arabidopsis thaliana. An in vitro enzymatic analysis of the recombinant CS26 protein demonstrated that this isoform possesses S-sulfocysteine synthase activity and lacks O-acetylserine(thiol)lyase activity. In vivo functional analysis of this enzyme in knockout mutants demonstrated that mutation of CS26 suppressed the S-sulfocysteine synthase activity that was detected in the wild type; furthermore, the cs26 mutants exhibited a reduction in size and showed paleness, but penetrance of the growth phenotype depended on the light regime. The cs26 mutant plants also had reductions in chlorophyll content and photosynthetic activity (neither of which were observed in oas-b mutants) as well as elevated glutathione levels. However, cs26 leaves were not able to properly detoxify reactive oxygen species, which accumulated to high levels under long-day growth conditions. The transcriptional profile of the cs26 mutant revealed that the mutation had a pleiotropic effect on many cellular and metabolic processes. Our findings reveal that S-sulfocysteine and the activity of S-sulfocysteine synthase play important roles in chloroplast function and are essential for light-dependent redox regulation within the chloroplast.

  在细菌中，Cys的生物合成是由cysK和cysM基因编码的两种酶完成的。CysM也能够使用硫代硫酸盐作为底物产生S-磺酰半胱氨酸。在植物细胞中，Cys的生物合成发生在细胞质、线粒体和叶绿体中。叶绿体含有两种O-乙酰丝氨酸（硫）裂解酶同源物，它们由拟南芥中的OAS-B和CS26基因编码。对重组CS26蛋白的体外酶学分析表明，该同功型具有S-磺酰半胱氨酸合成酶活性，缺乏O-乙酰丝氨酸（硫）裂解酶活性。对敲除突变体中该酶的体内功能分析表明，CS26的突变抑制了野生型中检测到的S-磺酰半胱氨酸合成酶活性；此外，cS26突变体表现出大小减小和苍白的特征，但生长表型的穿透性取决于光照条件。cS26突变体植株的叶片还表现出叶绿素含量和光合活性的降低（这些都没有在OAs-b突变体中观察到），以及谷胱甘肽水平的升高。然而，cS26叶片无法正确地解毒反应性氧化物，在长日生长条件下，这些氧化物积累到高水平。cS26突变体的转录谱揭示了该突变对许多细胞和代谢过程具有多向性影响。我们的研究结果揭示了S-磺酰半胱氨酸和S-磺酰半胱氨酸合成酶活性在叶绿体功能中发挥重要作用，并且对于叶绿体内的光依赖性氧化还原调节是必不可少的。

• Photosynthetic Adaptation to Length of Day Is Dependent on <i>S</i>-Sulfocysteine Synthase Activity in the Thylakoid Lumen  
  作者：María Ángeles Bermúdez、Jeroni Galmés、Inmaculada Moreno、Philip M. Mullineaux、Cecilia Gotor、Luis C. Romero

  DOI：10.1104/pp.112.201491

  日期：2012.9.3

  Arabidopsis (Arabidopsis thaliana) chloroplasts contain two O-acetyl-serine(thiol)lyase (OASTL) homologs, OAS-B, which is an authentic OASTL, and CS26, which has S-sulfocysteine synthase activity. In contrast with OAS-B, the loss of CS26 function resulted in dramatic phenotypic changes, which were dependent on the light treatment. We have performed a detailed characterization of the photosynthetic and chlorophyll fluorescence parameters in cs26 plants compared with those of wild-type plants under short-day growth conditions (SD) and long-day growth conditions (LD). Under LD, the photosynthetic characterization, which was based on substomatal CO2 concentrations and CO2 concentration in the chloroplast curves, revealed significant reductions in most of the photosynthetic parameters for cs26, which were unchanged under SD. These parameters included net CO2 assimilation rate, mesophyll conductance, and mitochondrial respiration at darkness. The analysis also showed that cs26 under LD required more absorbed quanta per driven electron flux and fixed CO2. The nonphotochemical quenching values suggested that in cs26 plants, the excess electrons that are not used in photochemical reactions may form reactive oxygen species. A photoinhibitory effect was confirmed by the background fluorescence signal values under LD and SD, which were higher in young leaves compared with mature ones under SD. To hypothesize the role of CS26 in relation to the photosynthetic machinery, we addressed its location inside of the chloroplast. The activity determination and localization analyses that were performed using immunoblotting indicated the presence of an active CS26 enzyme exclusively in the thylakoid lumen. This finding was reinforced by the observation of marked alterations in many lumenal proteins in the cs26 mutant compared with the wild type.

  拟南芥（Arabidopsis thaliana）叶绿体中含有两个O-乙酰丝氨酸（硫）裂解酶（OASTL）同源物，其中OAS-B是一个真正的OASTL，而CS26具有S-硫代半胱氨酸合成酶活性。与OAS-B相比，CS26功能的丧失导致了显著的表型变化，这取决于光照处理。我们在短日生长条件（SD）和长日生长条件（LD）下对cS26植株进行了光合和叶绿素荧光参数的详细表征，与野生型植株进行了比较。在LD下，基于气孔下CO2浓度和叶绿体曲线中 浓度的光合特性表征显示，cS26的大多数光合参数显著降低，而在SD下则保持不变。这些参数包括净 同化速率、肉质导度和暗期线粒体呼吸。分析还表明，在LD下，cS26需要更多吸收的光子数来驱动电子通量和固定 。非光化学猝灭值表明，在cS26植株中，未用于光化学反应的多余电子可能形成反应性氧化物质。在SD下，背景荧光信号值比成熟叶片高的年轻叶片中证实了光抑制效应。为了推测CS26在光合机器中的作用，我们研究了其在叶绿体内的位置。使用免疫印迹进行的活性测定和定位分析表明，在类囊体腔中仅存在活性的CS26酶。与野生型相比，cS26突变体中许多类囊体腔蛋白发生明显改变，加强了这一发现。

• Enzymatic proof for the identity of the S-sulfocysteine synthase and cysteine synthase B of Salmonella typhimurium
  作者：T Nakamura、H Iwahashi、Y Eguchi

  DOI：10.1128/jb.158.3.1122-1127.1984

  日期：1984.6

  S-Sulfocysteine synthase was isolated from Salmonella typhimurium LT-2 to homogeneous form with polyacrylamide gel electrophoresis. The molecular weight of this enzyme was determined to be ca. 55,000. The enzyme consisted of two identically sized subunits, and it contained one pyridoxal phosphate per subunit. The enzyme catalyzed the biosynthesis of cysteine or S-methylcysteine from sulfide or methanethiol and O-acetylserine, respectively, in addition to the formation of S-sulfocysteine from thiosulfate and O-acetylserine. The enzyme is identical to cysteine synthase B. The intracellular level of this enzyme was regulated by lesser extents of the same factors as those effective for cysteine synthase A.

  S-硫基半胱氨酸合成酶从鼠伤寒沙门氏菌LT-2中分离出纯化形式，并使用聚丙烯酰胺凝胶电泳确定了该酶的分子量约为55,000。该酶由两个相同大小的亚基组成，每个亚基含有一个吡哆醛磷酸盐。该酶催化了半胱氨酸或S-甲基半胱氨酸从硫化物或甲硫醇和O-乙酰丝氨酸中的生物合成，此外还催化了硫代硫酸盐和O-乙酰丝氨酸生成S-硫基半胱氨酸。该酶与半胱氨酸合成酶B相同。该酶的细胞内水平由与半胱氨酸合成酶A相同的因素调节。
• S-sulfocysteine synthase function in sensing chloroplast redox status
  作者：Cecilia Gotor、Luis C. Romero

  DOI：10.4161/psb.23313

  日期：2013.3

  The minor chloroplastic O-acetylserine(thiol)lyase isoform encoded by the CS26 gene in Arabidopsis thaliana has been described as an S-sulfocysteine synthase enzyme that plays an important role in chloroplast function. This enzyme is located in the thylakoid lumen, and its S-sulfocysteine activity is essential for the proper photosynthetic performance of the chloroplast under long-day growth conditions. Based on the present knowledge of this enzyme, we suggest that S-sulfocysteine synthase functions as a protein sensor to detect the accumulation of thiosulfate as a result of the inadequate detoxification of reactive oxygen species generated under conditions of excess light to produce the S-sulfocysteine molecule that triggers protection mechanisms of the photosynthetic apparatus.
• O-Acetylserine sulfhydrylase and S-sulfocysteine synthase activities of Rhodospirillum tenue
  作者：Gabriele Hensel、Hans G. Tr�per

  DOI：10.1007/bf00407763

  日期：1983.6

  O-Acetylserine sulfhydrylase in cell-free extracts of Rhodospirillum tenue was markedly repressed after growth in the presence of sulfide or thiosulfate, whereas S-sulfocysteine synthase activity remained almost unchanged. Purification on DE52 cellulose resulted in the separation of two proteins: Protein I with a molecular weight of 57000 had O-acetylserine sulfhydrylase activity only, while protein II with a molecular weight of 46000 had S-sulfocysteine synthase activity in addition. The activity of protein II with O-acetylserine plus sulfide was about 1.5 of that with O-acetylserine plus thiosulfate. Protein I from sulfate-grown cells possessed 74% of the total O-acetylserine sulfhydrylase, protein II 26%. Growth with sulfide repressed only the synthesis of protein I, which after separation showed only 19% of the measurable O-acetylserine sulfhydrylase, whereas protein II now possessed 81%. Regulatory and kinetic phenomena of the two activities were studied. In addition to the phototrophic bacteria studied earlier, also Rhodomicrobium vannielii, Rhodopseudomonas acidophila, Rhodocyclus purpureus and Thiocystis violacea were found to contain O-acetylserine sulfhydrylase activities; the latter two species contained S-sulfocysteine synthase activities in addition.