The Enzymatic and Metabolic Capabilities of Early Life
Figure 1
Metaconsensus analysis of conserved enzyme functions identified by three independent comparative bioinformatics methods.
These methods include comparisons of clusters of orthologous protein sequences [9], protein fold architectures [26], and metabolic reactions [21]. Members in each of these datasets are converted to enzyme functions represented by a three-term EC code and the resulting datasets are made nonredundant. Six metaconsensus enzyme functions are found in all three datasets and thus are very likely to have been present in LUCA. Because the universal reactions data were acquired by comparing only autotrophic organisms, this analysis may be overly dependent on whether or not LUCA was also autotrophic. Thus, the four EC groups common between the universal sequence and universal structure datasets, but not present in the universal reaction dataset, are also likely to have been present in LUCA.