Dendrogram of amino acid sequences of old yellow enzymes (OYEs) from Rhodococcus opacus 1CP and characterized OYE enzymes. The maximum likelihood distance tree was solved by usage of Mega 6.06-mac with Clustal W alignment method. Test of phylogeny was performed with 500 bootstrap replications, and resulting numbers are indicated. ‘Thermophilic-like’ OYEs are indicated by a light gray box. Melting temperatures of ‘thermophilic-like’ OYEs are indicated by symbols colored with respect to the thermogram. NCBI accession numbers are in parentheses. OYE1: Saccharomyces pastorianus (carlsbergensis, CAA37666), OYE3: S. cerevisiae (CAA97878), KYE1: Kluyveromyces lactis (AAA98815), EBP1: Candida albicans (AAA18013), OPR1: Solanum lycopersicum (CAB43506), OPR3: S. lycopersicum (CAC21424), NerA: Agrobacterium tumefaciens (CAA74280), MR: Pseudomonas putida (AAC43569), OYERo1 and OYERo3: R. opacus 1CP, NemA: Escherichia coli (BAA13186), PETNR: Enterobacter cloacae (AAB38638), SYE2: Shewanella oneidensis (AAN55487), Achr-OYE3: Achromobacter sp. JA81 (AFK73187), OYERo2 and OYERo4: R. opacus 1CP, RmER: Ralstonia (Cupriavidus) metallidurans CH34 (ABF11721), DrER: Deinococcus radiodurans R1 (AAF11740), TsER: Thermus scotoductus (CAP16804), XenA: P. putida (AAF02538), TOYE: Thermoanaerobacter pseudethanolicus (ABY93685), Chr-OYE3: Chryseobacterium sp. CA49 (AHV90721), YqjM: Bacillus subtilis (BAA12619), GkOYE: Geobacillus kaustophilus (BAD76617) and GeoER: Geobacillus sp. #30 (BAO37313).