Crystal structure of 2-phosphosulfolactate phosphatase (ComB) from Clostridium acetobutylicum at 2.6 Å resolution reveals a new fold with a novel active site
Crystal structure of 2-phosphosulfolactate phosphatase (ComB) from Clostridium acetobutylicum at 2.6 Å resolution reveals a new fold with a novel active site
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DOI：
10.1002/prot.20978
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发表时间：
2006-11-15
影响因子：
2.9
通讯作者：
Wilson, Ian A.
中科院分区：
文献类型：
--
作者：
DiDonato, Michael;Krishna, S. Sri;Wilson, Ian A.
导论.丙酮丁醇梭菌的2-磷酸硫代乳酸磷酸酶（ComB）基因编码分子量为26，012 Da（残基1-235）且计算的等电点为6.6的酶。ComB是Mg 2依赖性酸性磷酸酶，其催化辅酶M（CoM; 2-巯基乙磺酸）生物合成的第二步（EC 3.1. 3.71），即（2 R）-2-磷酸-3-磺酸乳酸盐水解生成（2 R）-3-磺酸乳酸盐和磷酸盐[图1（A）]。1 CoM是甲烷生成的末端甲基载体。产甲烷古菌开始通过磺化磷酸烯醇丙酮酸形成2-磷酸-3-磺基乳酸来产生这种必需的辅因子。脱磷酸化后，该前体被氧化，脱羧，然后还原硫醇化形成CoM。在所有可用的蓝藻基因组序列中以及在来自遗传多样性细菌和古细菌的基因组中已经鉴定了ComB的同源物。1，2然而，这些生物中的许多缺乏其他CoM生物合成基因的同源物。已知来自詹氏甲烷球菌的ComB酶作用于底物的两种立体异构体，并水解许多（S）-2-羟基羧酸的磷酸单酯。1催化CoM生物合成第一步的ComA的晶体结构已被报道。3在此，我们报告了ComB的晶体结构，这是使用结构基因组学联合中心（JCSG）的半自动化，高通量管道确定的。4结果与讨论使用多波长异常衍射（MAD）方法测定ComB的晶体结构[图1（B）]，标称分辨率为2.6 nm。数据收集、模型和细化统计总结见表I。最终模型包括三个
Introduction. The 2-phosphosulfolactate phosphatase (ComB) gene of Clostridium acetobutylicum encodes an enzyme with a molecular weight of 26,012 Da (residues 1–235) and a calculated isoelectric point of 6.6. ComB is a Mg2-dependent acid phosphatase that catalyzes the second step in Coenzyme M (CoM; 2-mercaptoethanesulfonic acid) biosynthesis (EC 3.1. 3.71), namely, the hydrolysis of (2R)-2-phospho-3-sulpholactate to yield (2R)-3-sulpholactate and phosphate [Fig. 1 (A)]. 1 CoM is the terminal methyl carrier in methanogenesis. Methanogenic archaea begin the production of this essential cofactor by sulfonating phosphoenolpyruvate to form 2-phospho-3-sulfolactate. After dephosphorylation, this precursor is oxidized, decarboxylated, and then reductively thiolated to form CoM. Homologs of ComB have been identified in all available cyanobacterial genome sequences and in genomes from phylogenetically diverse bacteria and archaea. 1, 2 However, many of these organisms lack homologs of other CoM biosynthetic genes. The ComB enzyme from Methanococcus jannaschii is known to act on both stereoisomers of the substrate, and hydrolyzes a number of phosphate monoesters of (S)-2-hydroxycarboxylic acids. 1 The crystal structure of ComA, which catalyzes the first step of CoM biosynthesis, has been reported previously. 3 Herein, we report the crystal structure of ComB, which was determined using the semiautomated, high-throughput pipeline of the Joint Center for Structural Genomics (JCSG). 4Results and Discussion. The crystal structure of ComB [Fig. 1 (B)] was determined to a nominal resolution of 2.6 Å using the multi-wavelength anomalous diffraction (MAD) method. Data collection, model, and refinement statistics are summarized in Table I. The final model includes three