Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
Chem Biol Interact. 2013 Feb 25;202(1-3):91-6. doi: 10.1016/j.cbi.2012.11.008. Epub 2012 Nov 28.
Different lines of alcohol dehydrogenases (ADHs) have separate superfamily origins, already recognized but now extended and re-evaluated by re-screening of the latest databank update. The short-chain form (SDR) is still the superfamily with most abundant occurrence, most multiple divergence, most prokaryotic emphasis, and most non-complicated architecture. This pattern is compatible with an early appearance at the time of the emergence of prokaryotic cellular life. The medium-chain form (MDR) is also old but second in terms of all the parameters above, and therefore compatible with a second emergence. However, this step appears seemingly earlier than previously considered, and may indicate sub-stages of early emergences at the increased resolution available from the now greater number of data entries. The Zn-MDR origin constitutes a third stage, possibly compatible with the transition to oxidative conditions on earth. Within all these three lines, repeated enzymogeneses gave the present divergence. MDR-ADH origin(s), at a fourth stage, may also be further resolved in multiple or extended modes, but the classical liver MDR-ADH of the liver type can still be traced to a gene duplication ~550 MYA (million years ago), at the early vertebrate radiation, compatible with the post-eon-shift, "Cambrian explosion". Classes and isozymes correspond to subsequent and recent duplicatory events, respectively. They illustrate a peculiar pattern with functional and emerging evolutionary distinctions between parent and emerging lines, suggesting a parallelism between duplicatory and mutational events, now also visible at separate sub-stages. Combined, all forms show distinctive patterns at different levels and illustrate correlations with global events. They further show that simple molecular observations on patterns, multiplicities and occurrence give much information, suggesting common divergence rules not much disturbed by horizontal gene transfers after the initial origins.
不同的醇脱氢酶（ADH）家族具有不同的超家族起源，这一点已经得到认可，但现在通过重新筛选最新的数据库更新，已经得到扩展和重新评估。短链形式（SDR）仍然是超家族中出现频率最高、分化程度最高、原核生物强调程度最高、结构最简单的一种。这种模式与原核细胞生命出现时的早期出现相吻合。中链形式（MDR）也很古老，但在上述所有参数中排名第二，因此与第二次出现相吻合。然而，这一步似乎比之前认为的更早，可能表明在可用数据条目数量增加的情况下，早期出现的分阶段更早。Zn-MDR 起源构成了第三个阶段，可能与地球上氧化条件的转变相适应。在这三个谱系中，重复的酶原发生导致了目前的分化。MDR-ADH 的起源（s），在第四个阶段，也可能以多种或扩展的模式进一步分化，但经典的肝脏 MDR-ADH 仍然可以追溯到 5.5 亿年前（百万年前）的早期脊椎动物辐射时期，与后元转变、“寒武纪大爆发”相吻合。类和同工酶分别对应于随后的和最近的复制事件。它们说明了一种特殊的模式，具有功能和新兴进化的区别，表明复制和突变事件之间存在平行关系，现在在单独的亚阶段也可以看到。所有形式都在不同层次上表现出独特的模式，并与全球事件相关联。它们进一步表明，对模式、多样性和出现的简单分子观察提供了大量信息，表明在最初起源后，水平基因转移并没有对共同的分化规则造成太大干扰。
