Role of glutamine synthetase adenylylation in the self-protection of Pseudomonas syringae subsp. "tabaci" from its toxin, tabtoxinine-beta-lactam
Role of glutamine synthetase adenylylation in the self-protection of Pseudomonas syringae subsp. "tabaci" from its toxin, tabtoxinine-beta-lactam
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谷氨酰胺合成酶腺苷酸化在丁香假单胞菌亚种自我保护中的作用。
DOI：
10.1128/jb.166.1.224-229.1986
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发表时间：
1986
影响因子：
3.2
通讯作者：
P. J. Langston
中科院分区：
文献类型：
--
作者：
T. J. Knight;R. Durbin;P. J. Langston
选择的假单胞菌的致病变种产生细胞外植物毒素，tabtoxinine-β-内酰胺，不可逆地抑制其已知的生理靶标，谷氨酰胺合成酶（GS）。葡萄假单胞菌“烟粉虱”在培养物中产生毒素期间保留了大量的谷氨酰胺合成酶活性。作为我们研究这些致病变种所使用的自我保护机制的一部分，我们已经确定GS在毒素产生开始后变为腺苷酸化，并且从tabtoxin的锌活化水解释放的丝氨酸是这种腺苷酸化开始的因素。该GS的腺苷酸化状态估计为E5.0-7.5。通过tabtoxinine-β-内酰胺对从P.“烟粉虱”进行了调查。腺苷酰化的GS被tabtoxinine-β-内酰胺以比未腺苷酰化的酶更慢的速率灭活。腺苷酰化GS（E7.5-10.5）的显着保护，从这种失活的酶效应子，AMP，Ala，Gly，His和Ser的存在下。因此，组合的腺苷酰化GS毒素产生后，启动和酶效应子的存在下，在体内可以提供的一部分，使用的subsp.烟粉虱
Selected pathovars of Pseudomonas syringae produce an extracellular phytotoxin, tabtoxinine-beta-lactam, that irreversibly inhibits its known physiological target, glutamine synthetase (GS). Pseudomonas syringae subsp. "tabaci" retains significant amounts of glutamine synthetase activity during toxin production in culture. As part of our investigation of the self-protection mechanism(s) used by these pathovars, we have determined that GS becomes adenylylated after toxin production is initiated and that the serine released from the zinc-activated hydrolysis of tabtoxin is a factor in the initiation of this adenylylation. The adenylylation state of this GS was estimated to range from E5.0-7.5. The irreversible inactivation by tabtoxinine-beta-lactam of unadenylylated and adenylylated glutamine synthetase purified from P. syringae subsp. "tabaci" was investigated. Adenylylated GS was inactivated by tabtoxinine-beta-lactam at a slower rate than was unadenylylated enzyme. Adenylylated GS (E7.5-10.5) was significantly protected from this inactivation in the presence of the enzyme effectors, AMP, Ala, Gly, His, and Ser. Thus, the combination of the adenylylation of GS after toxin production is initiated and the presence of the enzyme effectors in vivo could provide part of the self-protection mechanism used by subsp. "tabaci".