Vimal Archana, Kumar Awanish
Department of Biotechnology, National Institute of Technology (NIT), Raipur, India.
Department of Biotechnology, National Institute of Technology (NIT), Raipur, India.
Enzyme Microb Technol. 2017 Mar;98:9-17. doi: 10.1016/j.enzmictec.2016.12.001. Epub 2016 Dec 9.
l-asparaginase is an enzyme of medical prominence and reputable as a chemotherapeutic agent. It also has immense potential to cure autoimmune and infectious diseases. The vast application of this enzyme in healthcare sector increases its market demand. However, presently the huge market demand is not achieved completely. This serves the basis to explore better producer microbial strains to bridge the gap between huge demand and supply of this therapeutic enzyme. The present study deals with the successful screening of potent microorganisms producing l-asparaginase. 47 microorganisms were screened including bacteria, fungi, and yeasts. Among all, Penicillium lilacinum showed the highest enzyme activity i.e., 39.67 IU/ml. Shigella flexneri has 23.21 IU/ml of enzyme activity (highest among all the bacterial strain tested). Further, the 3-D structure of l-asparaginase from higher producer strains was developed and validated in silico for its activity. l-asparagine (substrate for l-asparaginase) was docked inside the binding pocket of P. lilacinum and S. flexneri. Docking score for the most common substrate l-asparagine is -6.188 (P. lilacinum), -5.576 (S. flexneri) which is quite good. Moreover, the chemical property of the binding pocket revealed that amino acid residues Phe 243, Gln 260, Gly 365, Asp 386 in P. lilacinum and residues Asp 181, Thr 318, Asn 320 in S. flexneri have an important role in H-bonding. The in silico results supports and strengthen the wet lab results. The outcome obtained motivates to take the present study result from lab to industry for the economic/massive production of this enzyme for the diverse therapeutic application.
L-天冬酰胺酶是一种具有医学重要性的酶，作为一种化疗药物颇负盛名。它在治疗自身免疫性疾病和传染病方面也具有巨大潜力。这种酶在医疗保健领域的广泛应用增加了其市场需求。然而，目前巨大的市场需求尚未得到完全满足。这为探索更好的生产微生物菌株以弥合这种治疗性酶的巨大供需差距提供了依据。本研究致力于成功筛选出产生L-天冬酰胺酶的高效微生物。共筛选了47种微生物，包括细菌、真菌和酵母。其中，淡紫拟青霉表现出最高的酶活性，即39.67 IU/ml。福氏志贺菌的酶活性为23.21 IU/ml（在所测试的所有细菌菌株中最高）。此外，对高产菌株的L-天冬酰胺酶的三维结构进行了虚拟开发并验证其活性。L-天冬酰胺（L-天冬酰胺酶的底物）对接在淡紫拟青霉和福氏志贺菌的结合口袋内。最常见底物L-天冬酰胺的对接分数为-6.188（淡紫拟青霉）、-5.576（福氏志贺菌），相当不错。此外，结合口袋的化学性质表明，淡紫拟青霉中的氨基酸残基Phe 243、Gln 260、Gly 365、Asp 386以及福氏志贺菌中的残基Asp 181、Thr 318、Asn 320在氢键形成中起重要作用。虚拟结果支持并强化了湿实验室结果。所获得的结果促使将本研究结果从实验室应用于工业，以便经济/大规模生产这种酶用于各种治疗应用。
