Evolution of assisted protein folding: The distribution of the main chaperoning systems within the phylogenetic domain archaea
Evolution of assisted protein folding: The distribution of the main chaperoning systems within the phylogenetic domain archaea
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DOI：
10.2741/1328
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发表时间：
2004-05-01
影响因子：
3.1
通讯作者：
de Macario, EC
中科院分区：
文献类型：
--
作者：
Macario, AJL;Malz, M;de Macario, EC
新生成的蛋白质必须达到功能性形状，即天然构型，才能在细胞中发挥其生理作用。蛋白质也必须前往现场（e。例如，在一个实施例中，在细胞中需要它们的功能。在这些折叠成天然构型并移位到工作位置的过程中，蛋白质可以由称为分子伴侣的分子协助。压力源可以解折叠（变性）蛋白质，遗传缺陷可能导致错误折叠，此外，这两种异常都可能导致多肽聚集。分子伴侣在帮助部分变性或错误折叠的蛋白质重折叠中起作用，从而防止聚集。显然，分子伴侣在正常的生理环境下以及在由环境或遗传因素引起的潜在有害情况下是关键的细胞组分。因此，分子伴侣构成了各种努力的有吸引力的靶标，这些努力旨在改善细胞的性能，特别是在应激下，以预防疾病，或至少减缓其进展并抑制应激的有害作用。在我们的努力，在这个方向上，我们已经着手调查伴侣系统的细胞属于系统发生域的chaperoning。这里报道的研究结果涉及古细菌中分子伴侣机器、伴侣蛋白和前折叠蛋白的分布。编码分子伴侣机器组分的基因hsp70（dnaK）、hsp40（dnaJ）和grpE只存在于一些古细菌物种中：这与细菌和真核生物形成对比，细菌和真核生物没有已知的例外。组I，或细菌，伴侣蛋白基因groEL和groES发生在甲烷八叠球菌属物种的基因组中，但没有发现在任何其他古细菌的基因组已被测序。虽然所有研究的古生菌都有一个到三个II组（热小体亚基）的伴侣蛋白，但食乙酸甲烷八叠球菌是例外，因为它有五个这样的伴侣蛋白。这是在原核生物中发现的最大数量的第二组伴侣蛋白。此外，两个M。食醋酵母伴侣蛋白与组II的其它已知古菌和真核伴侣蛋白不同，尽管与组II的其它已知古菌和真核伴侣蛋白相关。在所有的古细菌中发现了前折叠蛋白。总的来说，这些结果为伴侣系统的进化提供了线索，自从生命开始以来，伴侣系统在生存中发挥了关键作用。此外，这些数据表明了新的研究途径，用于阐明辅助蛋白质折叠的进化，并揭示这些分子尚未描述的作用和相互作用。
Newly made proteins must achieve a functional shape, the native configuration, before they can play their physiological roles in the cell. Proteins must also travel to the locale ( e. g., the mitochondrion) in the cell where their functions are required. In these processes of folding into the native configuration and translocation to the place of work, proteins may be assisted by molecules called molecular chaperones. Stressors can unfold ( denature) proteins, and genetic defects can cause misfolding and, in addition, both abnormalities can lead to polypeptide aggregation. Chaperones play a role in assisting refolding of partially denatured or misfolded proteins, thus preventing aggregation. Clearly, molecular chaperones are key cell components under normal, physiological circumstances, as well as in potentially harmful situations resulting from environmental or inherited factors. Hence, molecular chaperones constitute attractive targets for a variety of efforts aiming at improving the cell's performance, particularly under stress, to prevent disease, or at least to slow down its progression and to contain the deleterious effects of stress. In our efforts in this direction, we have undertaken to investigate the chaperoning systems of cells belonging to the phylogenetic domain Archaea. The findings reported here pertain to the distribution of the molecular chaperone machine, the chaperonins, and the prefoldins, among archaea. The genes hsp70(dnaK), hsp40(dnaJ), and grpE encoding the components of the molecular chaperone machine were present only in some archeaeal species: this contrasts with bacteria and eucarya, which do have the genes with no known exception. The group I, or bacterial, chaperonin-genes groEL and groES occured in the genomes of Methanosarcina species but were not found in any of the other archaea whose genomes have been sequenced. While all the archaea studied had between one and three chaperonins of group II ( thermosome subunits), Methanosarcina acetivorans was exceptional since it had five of these chaperonins. This is the largest number of group II chaperonins ever found in a prokaryote. Furthermore, two of the M. acetivorans chaperonins were different from, albeit related to, the other known archaeal and eucaryal chaperonins of group II. Prefoldins were found in all archaea examined. Overall, the results provide clues to the evolution of the chaperoning systems, which must have played a critical role in survival since life started. Also, the data suggest new avenues of research for elucidating the evolution of assisted protein folding and for uncovering roles and interactions not yet described for these molecules.