4z17
Thermostable enolase from Chloroflexus aurantiacus
Structural highlights
FunctionENO_CHLAA Catalyzes the reversible conversion of 2-phosphoglycerate into phosphoenolpyruvate. It is essential for the degradation of carbohydrates via glycolysis. Publication Abstract from PubMedEnolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate during both glycolysis and gluconeogenesis, and is required by all three domains of life. Here, we report the purification and biochemical and structural characterization of enolase from Chloroflexus aurantiacus, a thermophilic anoxygenic phototroph affiliated with the green non-sulfur bacteria. The protein was purified as a homodimer with a subunit molecular weight of 46 kDa. The temperature optimum for enolase catalysis was 80 degrees C, close to the measured thermal stability of the protein which was determined to be 75 degrees C, while the pH optimum for enzyme activity was 6.5. The specific activities of purified enolase determined at 25 and 80 degrees C were 147 and 300 U mg(-1) of protein, respectively. K m values for the 2-phosphoglycerate/phosphoenolpyruvate reaction determined at 25 and 80 degrees C were 0.16 and 0.03 mM, respectively. The K m values for Mg(2+) binding at these temperatures were 2.5 and 1.9 mM, respectively. When compared to enolase from mesophiles, the biochemical and structural properties of enolase from C. aurantiacus are consistent with this being thermally adapted. These data are consistent with the results of our phylogenetic analysis of enolase, which reveal that enolase has a thermophilic origin. Biochemical and Structural Characterization of Enolase from Chloroflexus aurantiacus: Evidence for a Thermophilic Origin.,Zadvornyy OA, Boyd ES, Posewitz MC, Zorin NA, Peters JW Front Bioeng Biotechnol. 2015 Jun 1;3:74. doi: 10.3389/fbioe.2015.00074., eCollection 2015. PMID:26082925[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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