On the illusion of auxotrophy: met15Δ yeast cells can grow on inorganic sulfur, thanks to the previously uncharacterized homocysteine synthase Yll058w.
On the illusion of auxotrophy: met15Δ yeast cells can grow on inorganic sulfur, thanks to the previously uncharacterized homocysteine synthase Yll058w.
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DOI：
10.1016/j.jbc.2022.102697
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发表时间：
2022-12
影响因子：
4.8
通讯作者：
Carvunis, Anne-Ruxandra
中科院分区：
文献类型：
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作者：
Van Oss, S. Branden;Parikh, Saurin Bipin;Coelho, Nelson Castilho;Wacholder, Aaron;Belashov, Ivan;Zdancewicz, Sara;Michaca, Manuel;Xu, Jiazhen;Kang, Yun Pyo;Ward, Nathan P.;Yoon, Sang Jun;McCourt, Katherine M.;McKee, Jake;Ideker, Trey;VanDemark, Andrew P.;DeNicola, Gina M.;Carvunis, Anne-Ruxandra
生物体必须合成或同化必需的有机化合物才能生存。自20世纪70年代发现以来，同型半胱氨酸合酶Met15一直被认为是酵母中无机硫同化所必需的。因此，MET 15已作为遗传标记用于数百个在真核生物遗传学和系统生物学中发挥基础作用的实验。然而，我们在这里证明，通过结构和进化建模，体外动力学测定，和遗传互补，一个替代的同型半胱氨酸合酶编码的先前未表征的基因YLL058W使细胞缺乏Met15同化足够的无机硫的生存和增殖。然而，这些细胞不能在贴片或液体培养物中生长，除非提供有外源性甲硫氨酸或其它有机硫。我们发现，这种生长失败，这在历史上证明了MET 15作为一个经典的营养缺陷型标志物的地位，在很大程度上是由于代谢瓶颈的气体硫化氢的毒性积累解释。当用硫化氢螯合剂贴敷或培养时，以及当作为集落网格繁殖时，没有Met15的细胞同化无机硫并生长，而具有Met15的细胞实现甚至更高的产量。因此，Met15不是酵母无机硫同化所必需的。相反，MET 15是酵母基因的第一个例子，其损失以依赖于局部气体交换的方式有条件地阻止生长。我们的研究结果对硫代谢的研究，包括应激反应，蛋氨酸限制和衰老的研究具有广泛的意义。更一般地说，我们的发现说明了不受重视的实验变量如何混淆生物学发现。
Organisms must either synthesize or assimilate essential organic compounds to survive. The homocysteine synthase Met15 has been considered essential for inorganic sulfur assimilation in yeast since its discovery in the 1970s. As a result, MET15 has served as a genetic marker for hundreds of experiments that play a foundational role in eukaryote genetics and systems biology. Nevertheless, we demonstrate here through structural and evolutionary modeling, in vitro kinetic assays, and genetic complementation, that an alternative homocysteine synthase encoded by the previously uncharacterized gene YLL058W enables cells lacking Met15 to assimilate enough inorganic sulfur for survival and proliferation. These cells however fail to grow in patches or liquid cultures unless provided with exogenous methionine or other organosulfurs. We show that this growth failure, which has historically justified the status of MET15 as a classic auxotrophic marker, is largely explained by toxic accumulation of the gas hydrogen sulfide because of a metabolic bottleneck. When patched or cultured with a hydrogen sulfide chelator, and when propagated as colony grids, cells without Met15 assimilate inorganic sulfur and grow, and cells with Met15 achieve even higher yields. Thus, Met15 is not essential for inorganic sulfur assimilation in yeast. Instead, MET15 is the first example of a yeast gene whose loss conditionally prevents growth in a manner that depends on local gas exchange. Our results have broad implications for investigations of sulfur metabolism, including studies of stress response, methionine restriction, and aging. More generally, our findings illustrate how unappreciated experimental variables can obfuscate biological discovery.
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影响因子：
64.8
作者：
Jumper J;Evans R;Pritzel A;Green T;Figurnov M;Ronneberger O;Tunyasuvunakool K;Bates R;Žídek A;Potapenko A;Bridgland A;Meyer C;Kohl SAA;Ballard AJ;Cowie A;Romera-Paredes B;Nikolov S;Jain R;Adler J;Back T;Petersen S;Reiman D;Clancy E;Zielinski M;Steinegger M;Pacholska M;Berghammer T;Bodenstein S;Silver D;Vinyals O;Senior AW;Kavukcuoglu K;Kohli P;Hassabis D
通讯作者：
Hassabis D
影响因子：
5.3
作者：
Eder, Matthias;Sanchez, Isabelle;Dequin, Sylvie
通讯作者：
Dequin, Sylvie
影响因子：
56.9
作者：
Blackstone, E;Morrison, M;Roth, MB
通讯作者：
Roth, MB
影响因子：
16.6
作者：
Lu, Hongzhong;Li, Feiran;Nielsen, Jens
通讯作者：
Nielsen, Jens
DOI：
10.1007/bf00264692
发表时间：
1975-01-01
期刊：
MOLECULAR & GENERAL GENETICS
影响因子：
--
作者：
MASSELOT, M;ROBICHONSZULMAJSTER, HD
通讯作者：
ROBICHONSZULMAJSTER, HD