(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Thermotogae [phylum]: NE > Thermotogae [class]: NE > Thermotogales: NE > Thermotogaceae: NE > Thermotoga: NE > Thermotoga maritima: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MLFFIFMGILSILFAQEDVTVKSVTLITKVFPEGEKVCAVVIEYPVEIDG QKLSPDQFSVKVKTGDTYSSRTITKVYANNSGGLSFSIFNNRGKYVVLEL STEDLHSNTIVFGPNFLNTRMKLDYIVSQLVPIFDVDGNEVEPFTSKQTD EKHLIIDDFLAFTFKDPETGVEIPYRLFVPKDVNPDRKYPLVVFLHGAGE RGTDNYLQVAGNRGAVVWAQPRYQVVHPCFVLAPQCPPNSSWSTLFTDRE NPFNPEKPLLAVIKIIRKLLDEYNIDENRIYITGLSMGGYGTWTAIMEFP ELFAAAIPICGGGDVSKVERIKDIPIWVFHAEDDPVVPVENSRVLVKKLA EIGGKVRYTEYEKGFMEKHGWDPHGSWIPTYENQEAIEWLFEQSR
Comparative analysis of the genome of the hyperthermophilic bacterium Thermotoga maritima revealed a hypothetical protein (EstA) with typical esterase features. The EstA protein was functionally produced in Escherichia coli and purified to homogeneity. It indeed displayed esterase activity with optima at or above 95 degrees C and at pH 8.5, with a preference for esters with short acyl chains (C2-C10). Its 2.6-A-resolution crystal structure revealed a classical alpha/beta hydrolase domain with a catalytic triad consisting of a serine, an aspartate, and a histidine. EstA is irreversibly inhibited by the organophosphate paraoxon. A 3.0-A-resolution structure confirmed that this inhibitor binds covalently to the catalytic serine residue of EstA. Remarkably, the structure also revealed the presence of an N-terminal immunoglobulin (Ig)-like domain, which is unprecedented among esterases. EstA forms a hexamer both in the crystal and in solution. Electron microscopy showed that the hexamer in solution is identical with the hexamer in the crystal, which is formed by two trimers, with the N-terminal domains facing each other. Mutational studies confirmed that residues Phe89, Phe112, Phe116, Phe246, and Trp377 affect enzyme activity. A truncated mutant of EstA, in which the Ig-like domain was removed, showed only 5% of wild-type activity, had lower thermostability, and failed to form hexamers. These data suggest that the Ig-like domain plays an important role in the enzyme multimerization and activity of EstA.
Title: Crystallization and preliminary crystallographic analysis of an esterase with a novel domain from the hyperthermophile Thermotoga maritima Sun L, Levisson M, Hendriks S, Akveld T, Kengen SW, Dijkstra BW, Van der Oost J Ref: Acta Crystallographica Sect F Struct Biol Cryst Commun, 63:777, 2007 : PubMed
A predicted esterase (EstA) with an unusual new domain from the hyperthermophilic bacterium Thermotoga maritima has been cloned and overexpressed in Escherichia coli. The purified protein was crystallized by the hanging-drop vapour-diffusion technique in the presence of lithium sulfate and polyethylene glycol 8000. Selenomethionine-substituted EstA crystals were obtained under the same conditions and three different-wavelength data sets were collected to 2.6 A resolution. The crystal belongs to space group H32, with unit-cell parameters a = b = 130.2, c = 306.2 A. There are two molecules in the asymmetric unit, with a V(M) of 2.9 A3 Da(-1) and 58% solvent content.
The 1,860,725-base-pair genome of Thermotoga maritima MSB8 contains 1,877 predicted coding regions, 1,014 (54%) of which have functional assignments and 863 (46%) of which are of unknown function. Genome analysis reveals numerous pathways involved in degradation of sugars and plant polysaccharides, and 108 genes that have orthologues only in the genomes of other thermophilic Eubacteria and Archaea. Of the Eubacteria sequenced to date, T. maritima has the highest percentage (24%) of genes that are most similar to archaeal genes. Eighty-one archaeal-like genes are clustered in 15 regions of the T. maritima genome that range in size from 4 to 20 kilobases. Conservation of gene order between T. maritima and Archaea in many of the clustered regions suggests that lateral gene transfer may have occurred between thermophilic Eubacteria and Archaea.
Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)a EstA hypothetical 44.8 kda protein
