title: Interactions of non-natural halogenated substrates with D-specific dehalogenase (DehD) mutants usingin silicostudies.
abstract: The D-2-haloacid dehalogenase of D-specific dehalogenase (DehD) fromRhizobiumsp. RC1 catalyses the hydrolytic dehalogenation of D-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresponding L-hydroxyalkanoic acids. Our investigations were focused on DehD mutants: R134A and Y135A. We examined the possible interactions between these mutants with haloalkanoic acids and characterized the key catalytic residues in the wild-type dehalogenase, to design dehalogenase enzyme(s) with improved potential for dehalogenation of a wider range of substrates. Three natural substrates of wild-type DehD, specifically, monochloroacetate, monobromoacetate and D,L-2,3-dichloropropionate, and eight other non-natural haloalkanoic acids substrates of DehD, namely, L-2-chloropropionate; L-2-bromopropionate; 2,2-dichloropropionate; dichloroacetate; dibromoacetate; trichloroacetate; tribromoacetate; and 3-chloropropionate, were docked into the active site of the DehD mutants R134A and Y135A, which produced altered catalytic functions. The mutants interacted strongly with substrates that wild-type DehD does not interact with or degrade. The interaction was particularly enhanced with 3-chloropropionate, in addition to monobromoacetate, monochloroacetate and D,L-2,3-dichloropropionate. In summary, DehD variants R134A and Y135A demonstrated increased propensity for binding haloalkanoic acid and were non-stereospecific towards halogenated substrates. The improved characteristics in these mutants suggest that their functionality could be further exploited and harnessed in bioremediations and biotechnological applications.
authors.affiliation: Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering (FBME), Universiti Teknologi Malaysia , Johor Bahru , Johor , Malaysia.
authors.forename: Ismaila Yada
authors.initials: IY
authors.lastname: Sudi
authors.affiliation: Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering (FBME), Universiti Teknologi Malaysia , Johor Bahru , Johor , Malaysia.
authors.forename: Mohd Shahir
authors.initials: MS
authors.lastname: Shamsir
authors.affiliation: Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering (FBME), Universiti Teknologi Malaysia , Johor Bahru , Johor , Malaysia.
authors.forename: Haryati
authors.initials: H
authors.lastname: Jamaluddin
authors.affiliation: Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia , Johor Bahru , Johor , Malaysia.
authors.forename: Roswanira Abdul
authors.initials: RA
authors.lastname: Wahab
authors.affiliation: Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering (FBME), Universiti Teknologi Malaysia , Johor Bahru , Johor , Malaysia.
authors.forename: Fahrul
authors.initials: F
authors.lastname: Huyop
keywords: dehalogenases; docking; haloalkanoic acids; hydrogen-bond distance; interacting residues