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首页> 外文期刊>Journal of bacteriology >Instability of ackA (Acetate Kinase) Mutations and Their Effects on Acetyl Phosphate and ATP Amounts in Streptococcus pneumoniae D39
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Instability of ackA (Acetate Kinase) Mutations and Their Effects on Acetyl Phosphate and ATP Amounts in Streptococcus pneumoniae D39

机译：ackA（乙酸激酶）突变的不稳定性及其对肺炎链球菌D39中乙酰磷酸和ATP含量的影响

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Acetyl phosphate (AcP) is a small-molecule metabolite that can act as a phosphoryl group donor for response regulators of two-component systems (TCSs). The serious human respiratory pathogen Streptococcus pneumoniae (pneumococcus) synthesizes AcP by the conventional pathway involving phosphotransacetylase and acetate kinase, encoded by pta and ackA, respectively. In addition, pneumococcus synthesizes copious amounts of AcP and hydrogen peroxide (H2O2) by pyruvate oxidase, which is encoded by spxB. To assess possible roles of AcP in pneumococcal TCS regulation and metabolism, we constructed strains with combinations of spxB, pta, and ackA mutations and determined their effects on ATP, AcP, and H2O2 production. Unexpectedly, ΔackA mutants were unstable and readily accumulated primary suppressor mutations in spxB or its positive regulator, spxR, thereby reducing H2O2 and AcP levels, and secondary capsule mutations in cps2E or cps2C. ΔackA ΔspxB mutants contained half the cellular amount of ATP as a ΔspxB or spxB+ strain. Acetate addition and anaerobic growth experiments suggested decreased ATP, rather than increased AcP, as a reason that ΔackA mutants accumulated spxB or spxR suppressors, although experimental manipulation of the AcP amount was limited. This finding and other considerations suggest that coping with endogenously produced H2O2 may require energy. Starting with a ΔspxB mutant, we constructed Δpta, ΔackA, and Δpta ΔackA mutants. Epistasis and microarray experiment results were consistent with a role for the SpxB-Pta-AckA pathway in expression of the regulons controlled by the WalRKSpn, CiaRHSpn, and LiaSRSpn TCSs involved in sensing cell wall status. However, AcP likely does not play a physiological role in TCS sensing in S. pneumoniae.
机译：乙酰磷酸酯（AcP）是一种小分子代谢产物，可作为两组分系统（TCS）响应调节剂的磷酰基供体。严重的人类呼吸道病原体肺炎链球菌（肺炎球菌）通过磷酸转乙酰酶和乙酸激酶的常规途径合成AcP，分别由 pta 和 ackA 编码。此外，肺炎球菌通过丙酮酸氧化酶合成大量的AcP和过氧化氢（H 2 O 2 ），丙酮酸氧化酶由 spxB 编码。为了评估AcP在肺炎球菌TCS调节和代谢中的可能作用，我们构建了具有 spxB ， pta 和 ackA 突变的菌株，并确定了它们对ATP，AcP和H 2 O 2 产生的影响。出乎意料的是，Δ ackA 突变体不稳定，并且易于在s pxB 或其正调控子 spxR 中积累主要的抑制子突变，从而降低H 2 O 2 和AcP水平以及 cps2E 或 cps2C 中的继发性囊膜突变。 Δ ackA Δ spxB 突变体包含细胞数量的ATP，为Δ spxB 或 spxB + 应变。醋酸盐添加和厌氧生长实验表明，ATP降低而不是AcP升高，这是Δ ackA 突变体积累了 spxB 或 spxR 抑制剂的原因。 AcP量的实验操作受到限制。这一发现和其他考虑因素表明，应对内生产生的H 2 O 2 可能需要能量。从Δ spxB 突变体开始，我们构建了Δ pta ，Δ ackA 和Δ pta Δ ackA 突变体。上位性和微阵列实验结果与SpxB-Pta-AckA通路在WalRK Spn ，CiaRH 控制的调节子表达中的作用一致Spn 和LiaSR Spn TCS参与感知细胞壁状态。但是，AcP可能在 S的TCS传感中不发挥生理作用。肺炎。

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