| Title : Biochemical and biophysical characterisation of haloalkane dehalogenases DmrA and DmrB in Mycobacterium strain JS60 and their role in growth on haloalkanes - Fung_2015_Mol.Microbiol_97_439 |
| Author(s) : Fung HK , Gadd MS , Drury TA , Cheung S , Guss JM , Coleman NV , Matthews JM |
| Ref : Molecular Microbiology , 97 :439 , 2015 |
| Abstract : Haloalkane dehalogenases (HLDs) catalyse the hydrolysis of haloalkanes to alcohols, offering a biological solution for toxic haloalkane industrial wastes. Hundreds of putative HLD genes have been identified in bacterial genomes, but relatively few enzymes have been characterised. We identified two novel HLDs in the genome of Mycobacterium rhodesiae strain JS60, an isolate from an organochlorine-contaminated site: DmrA and DmrB. Both recombinant enzymes were active against C2-C6 haloalkanes, with a preference for brominated linear substrates. However, DmrA had higher activity against a wider range of substrates. The kinetic parameters of DmrA with 4-bromobutyronitrile as a substrate were Km = 1.9 +/- 0.2 mM, kcat = 3.1 +/- 0.2 s(-1) . DmrB showed the highest activity against 1-bromohexane. DmrA is monomeric, whereas DmrB is tetrameric. We determined the crystal structure of selenomethionyl DmrA to 1.7 A resolution. A spacious active site and alternate conformations of a methionine side-chain in the slot access tunnel may contribute to the broad substrate activity of DmrA. We show that M. rhodesiae JS60 can utilise 1-iodopropane, 1-iodobutane and 1-bromobutane as sole carbon and energy sources. This ability appears to be conferred predominantly through DmrA, which shows significantly higher levels of upregulation in response to haloalkanes than DmrB. |
| ESTHER : Fung_2015_Mol.Microbiol_97_439 |
| PubMedSearch : Fung_2015_Mol.Microbiol_97_439 |
| PubMedID: 25899475 |
| Gene_locus related to this paper: mycrh-g4i2j6 |
| Gene_locus related to this paper: mycrh-g4i2j6 |
Fung HK, Gadd MS, Drury TA, Cheung S, Guss JM, Coleman NV, Matthews JM (2015)
Biochemical and biophysical characterisation of haloalkane dehalogenases DmrA and DmrB in Mycobacterium strain JS60 and their role in growth on haloalkanes
Molecular Microbiology
97 :439
Fung HK, Gadd MS, Drury TA, Cheung S, Guss JM, Coleman NV, Matthews JM (2015)
Molecular Microbiology
97 :439