In world wide, the pesticides have facilitated the
development and also expansion of the agriculture. Organophosphate componds
were belonging to a class of highly toxic neurotoxins that are commonly used as
pesticides and also 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 of the organophosphate compound (Catherine
et al. 2002). The focussing of this study is organophosphorus hydrolase (OPH, E.C.
220.127.116.11), which catalyzes the hydrolysis of many organophosphorus compounds and
highly reduces the toxicity of organophosphate pesticide and it can able to 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). Although
OPH hydrolyzes a wide range of organophosphate compounds, the effectiveness of
hydrolysis varies dramatically for differnt compounds. Widely used organophosphorus
pesticides like methyl parathion, chlorpyrifos, and diazinon are hydrolyzed slowly
than 30 to 1,000 times is the preferred substrate, paraoxon (Cho et al. 2002).
This reduction in catalytic rate is due to the unfavorable interaction of these
substrates with the active sites involved in catalysis and structural functions
(Zheng et al. 2013).
A number of enzyme are capable of hydrolysing a
number of organophosphate triesters into non-toxic compounds. These enzymes are
possible bioremediators because of their ability to decontaminate OP-containing
environment like waters and soils (Zheng et al. 2013). The most thoroughly
characterized phosphotriesterases were isolated from Flavobacterium sp.
ATCC 27551, Pseudomonas diminuta (OPH) and Agrobacterium radiobacter (OpdA)
(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
had 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