SureshKumar Pandian, Thomas Jibu, Poornima Vasudevan
Algae Biomass Research Laboratory, Department of Biosciences and Technology, Karunya University, Coimbatore, Tamil Nadu, India.
Biochematics Laboratory, Department of Bioinformatics, Bharathiar University, Coimbatore, Tamil Nadu, India.
Environ Monit Assess. 2018 Jan 22;190(2):92. doi: 10.1007/s10661-017-6459-4.
Research on bioremediation of polycyclic aromatic hydrocarbons (PAHs) has established that several remediating microbial species are capable of degrading only low molecular weight (LMW)-PAHs, whereas high molecular weight (HMW)-PAHs are hardly degradable. In the present study, the efficiency of degradation of both LMW and HMW-PAHs by cytochrome P450 monooxygenase (CYP) of microalgae was studied. CYP have a key role in the detoxification of xenobiotics. So far, the structure of CYP in microalgae is not predicted; the protein structure was constructed by molecular modelling in the current study using the available template of microalgal CYP. Modelled microalgae 3D structures were docked against 38 different PAH compounds, and the information regarding the interaction between protein and PAHs viz. binding sites along with mode of interactions was investigated. We report that CYP from the microalgae Haematococcus pluvialis and Parachlorella kessleri was found to possess broad oxidising capability towards both LMW and HMW-PAHs. P. kessleri showed a least value with extra precision glide score of - 10.23 and glide energy of - 23.48 kcal/mol. PAHs bind to CYP active sites at Lys , Trp , Gln and Arg through intermolecular hydrogen bonding. Also, study revealed that PAHs interacted with CYP active sites through intermolecular hydrogen bonding, hydrophobic bonding, π-π interactions and van der waals interactions. Thus, structural elucidation study confirms that microalgae Parachlorella kessleri have the capacity to remediate HMW more efficiently than other microorganisms. Our results provide a framework in understanding the structure and the possible binding sites of CYP protein for degradation of PAH and that could be a screening tool in identifying the phycoremediation potential.
多环芳烃（PAHs）生物修复的研究表明，几种修复微生物仅能降解低分子量（LMW）-PAHs，而高分子量（HMW）-PAHs则几乎不可降解。在本研究中，研究了微藻细胞色素P450单加氧酶（CYP）对LMW和HMW-PAHs的降解效率。CYP在异源生物解毒中起关键作用。到目前为止，微藻中CYP的结构尚未预测；在本研究中，利用微藻CYP的可用模板通过分子建模构建了蛋白质结构。将模拟的微藻三维结构与38种不同的PAH化合物进行对接，并研究了蛋白质与PAHs之间相互作用的信息，即结合位点以及相互作用模式。我们报告称，雨生红球藻和克氏小球藻中的CYP对LMW和HMW-PAHs均具有广泛的氧化能力。克氏小球藻的额外精度滑动评分最低，为-10.23，滑动能量为-23.48 kcal/mol。PAHs通过分子间氢键与CYP活性位点的赖氨酸、色氨酸、谷氨酰胺和精氨酸结合。此外，研究还表明，PAHs通过分子间氢键、疏水键、π-π相互作用和范德华相互作用与CYP活性位点相互作用。因此，结构解析研究证实，克氏小球藻比其他微生物更有能力更有效地修复HMW。我们的结果为理解CYP蛋白降解PAH的结构和可能的结合位点提供了一个框架，这可能是一种识别藻修复潜力的筛选工具。
