Identification and characterization of carboxyl esterases of gill chamber-associated microbiota in the deep-sea shrimp rimicaris exoculata by using functional metagenomics
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Identification and characterization of carboxyl esterases of gill chamber-associated microbiota in the deep-sea shrimp rimicaris exoculata by using functional metagenomics
Alcaide, María; Tchigvintsev, Anatoli; Martinez-Martinez, Monica; Popovic, Ana; Reva, Oleg N.; Lafraya, Alvaro; Bargiela, Rafael; Nechitaylo, Taras Y.; Matesanz, Ruth; Cambon-Bonavita, Marie-Ann; Jebbar, Mohamed; Yakimov, Michail M.; Savchenko, Alexei; Golyshina, Olga V.; Yakunin, Alexander F.; Golyshin, Peter N.; Ferrer, Manuel; The MAMBA Consortium
The shrimp Rimicaris exoculata dominates the fauna in deep-sea hydrothermal vent sites along the Mid-Atlantic Ridge (depth,
2,320 m). Here, we identified and biochemically characterized three carboxyl esterases from microbial communities inhabiting
the R. exoculata gill that were isolated by naive screens of a gill chamber metagenomic library. These proteins exhibit low to
moderate identity to known esterase sequences (<52%) and to each other (11.9 to 63.7%) and appear to have originated from
unknown species or from genera of Proteobacteria related to Thiothrix/Leucothrix (MGS-RG1/RG2) and to the Rhodobacteraceae
group (MGS-RG3). A library of 131 esters and 31 additional esterase/lipase preparations was used to evaluate the activity
profiles of these enzymes. All 3 of these enzymes had greater esterase than lipase activity and exhibited specific activities with
ester substrates (<356Umg 1) in the range of similar enzymes. MGS-RG3 was inhibited by salts and pressure and had a low
optimal temperature (30°C), and its substrate profile clustered within a group of low-activity and substrate-restricted marine
enzymes. In contrast, MGS-RG1 and MGS-RG2 were most active at 45 to 50°C and were salt activated and barotolerant. They
also exhibited wider substrate profiles that were close to those of highly active promiscuous enzymes from a marine hydrothermal
vent (MGS-RG2) and from a cold brackish lake (MGS-RG1). The data presented are discussed in the context of promoting
the examination of enzyme activities of taxa found in habitats that have been neglected for enzyme prospecting; the enzymes
found in these taxa may reflect distinct habitat-specific adaptations and may constitute new sources of rare reaction specificities.