The pesticides have facilitated the development and
also expansion of agriculture in world wide. Organophosphate belong to a class
of highly toxic neurotoxins that are commonly used as pesticides and chemical
warfare agent (Surekha Rani et al. 2008).
The continuous use of organophosphate in intensive quantity throughout the
world and their potential neurotoxicity to humans has wind to the development
of various efficient and safety scheme of bioremediation to plenty with their
wide dispersal in the ecosystem (Cho et al. 2002). Enzymatic degradation by
organophosphorus hydrolase (OPH) has received considerable attention. This
attention provides the possibility of both eco friendly and in situ
detoxification (Catherine et al. 2002). The focussing of this study is
organophosphorus hydrolase (OPH, E.C. 18.104.22.168), which catalyzes the hydrolysis
of many organophosphorus compounds and highly reduces the toxicity of organophosphate
pesticide and it can completely mineralize the organophosphate compounds.
The OPH enzyme was coded by opd gene, were found
in two soil microorganisms namely Pseudomonas diminuta MG and Flavobacterium
sp. (Sethunathan et al. 1998). OPH hydrolyzes a wide range of
organophosphate compounds and the effectiveness of hydrolysis varies
dramatically for differnt compounds like widely used organophosphorus
insecticides methyl parathion, chlorpyrifos, and diazinon are hydrolyzed slowler
than paraoxon (Cho et al. 2002). The catalytic rate is reduced due to the unfavorable
interaction of the substrates with the active sites involved in catalysis and also
structural functions (Zheng et al. 2013).
A number of enzymes can able to hydrolysis a number
of organophosphate trimesters compound into less or non-toxic compound. OPH having
the ability to hydrolyzing the P–S bond of phosphonothioate esters. This enzyme
is a possible bioremediator because of their ability to decontaminate
OP-containing waters and soils (Zheng et al. 2013). The phosphotriesterases isolated
from Flavobacterium sp. ATCC 27551, Pseudomonas diminuta (OPH)
and Agrobacterium radiobacter (OpdA) was thoroughly characterized as a
bioremidiator (Fernanda et al. 2010). These enzymes belong to the binuclear metallohydrolase
family and share high sequence and structural homology. Phosphotriesterases are
highly promiscuous enzymes, hydrolysing a large range of substrates. The
phosphotriester hydrolysis by OPH has been studied extensively (Castro et al. 2016).
In a proposed reaction scheme, based on largely crystal structures with bound
inhibitors, the phosphoryl oxygen of the substrate binds to the ?-metal
ion (Janet et al.2005; Laothanachareo et al. 2008).
In the present research focuses on the interaction
and degradation of chlorpyrifos by OPH enzyme, as this is responsible for
detoxification. The molecular docking study was conducted under FlexX docking