4p08 | pdb_00004p08
Engineered thermostable dimeric cocaine esterase
Structural highlights
FunctionCOCE_RHOSM Hydrolyzes cocaine to benzoate and ecgonine methyl ester, endowing the bacteria with the ability to utilize cocaine as a sole source of carbon and energy for growth, as this bacterium lives in the rhizosphere of coca plants. Also efficiently hydrolyzes cocaethylene, a more potent cocaine metabolite that has been observed in patients who concurrently abuse cocaine and alcohol. Is able to prevent cocaine-induced convulsions and lethality in rat.[1] [2] [3] Publication Abstract from PubMedCocaine esterase (CocE) is known as the most efficient natural enzyme for cocaine hydrolysis. The major obstacle to the clinical application of wild-type CocE is the thermoinstability with a half-life of only approximately 12 min at 37 degrees C. The previously designed T172R/G173Q mutant (denoted as enzyme E172-173) with an improved in vitro half-life of approximately 6 h at 37 degrees C is currently in clinical trial Phase II for cocaine overdose treatment. Through molecular modeling and dynamics simulation, we designed and characterized a promising new mutant of E172-173 with extra L196C/I301C mutations (denoted as enzyme E196-301) to produce cross-subunit disulfide bonds that stabilize the dimer structure. The cross-subunit disulfide bonds were confirmed by X-ray diffraction. The designed L196C/I301C mutations have not only considerably extended the in vitro half-life at 37 degrees C to >100 days, but also significantly improved the catalytic efficiency against cocaine by approximately 150%. In addition, the thermostable E196-301 can be PEGylated to significantly prolong the residence time in mice. The PEGylated E196-301 can fully protect mice from a lethal dose of cocaine (180 mg/kg, LD100) for at least 3 days, with an average protection time of approximately 94h. This is the longest in vivo protection of mice from the lethal dose of cocaine demonstrated within all studies using an exogenous enzyme reported so far. Hence, E196-301 may be developed to become a more valuable therapeutic enzyme for cocaine abuse treatment, and it demonstrates that a general design strategy and protocol to simultaneously improve both the stability and function are feasible for rational protein drug design. Rational Design, Preparation, and Characterization of a Therapeutic Enzyme Mutant with Improved Stability and Function for Cocaine Detoxification.,Fang L, Chow KM, Hou S, Xue L, Chen X, Rodgers DW, Zheng F, Zhan CG ACS Chem Biol. 2014 Jun 11. PMID:24919140[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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