Evolutionary Analysis
Aiming to analyze if the promiscuous activities of albumins are physiologically relevant reaction mechanisms, we decided to study the evolutionary bases of the promiscuous reaction aldol condensation, characterized in our previous works12,14. The coding gene sequences and homologous proteins used for this purpose were obtained using BLAST25, using human serum albumin like query. and the multiple sequence alignment of serum albumins was constructed using the Clustal algorithm26. A total number of 46 representative sequences of different organisms, with known structures (121 total structures in the PDB27), were included in the analysis (see Supplementary Table 1). The evolutionary tree was estimated using Phyml28with the JTT model of evolution, experimental frequencies, and a gamma distribution of rate variation among sites. Also, nonparametric bootstrapping with 100 replicas was applied. To estimate the sites subject to positive selection, we used the mixed-effects model of evolution (MEME)29available for execution in the Datamonkey service30. The residues under positive selection were mapped to the structures in order to estimate structural and functional relationships.