title: Cloning, expression and characterization of NADP-dependent isocitrate dehydrogenase from Staphylococcus aureus.
abstract: The Krebs cycle dictates oxidative and reductive conditions in Staphylococcus aureus and is mainly regulated by isocitrate dehydrogenase (IDH) which plays pivotal role in the growth and pathogenesis of the bacteria. In the present study, IDH gene from S. aureus ATCC12600 was cloned in the Sma I site of pQE 30 vector; the resultant clone was named as UVIDH1. The insert in the clone was sequenced (accession number HM067707), and the sequence showed complete homology with IDH sequence of other S. aureus strains reported in the database indicating presence of single enzyme in S. aureus, and considerable sequence homology with other bacteria was observed; however, only 24% homology was found with NADP-dependent human IDH. Phylogenetically, the S. aureus IDH showed close identity with Bacillus subtilis and high degree of variability with other bacteria and human IDH. The expression of IDH in the clone UVIDH1 was induced with 1 mM IPTG, and the recombinant IDH was purified by passing through nickel metal chelate column; the purified recombinant IDH showed a single band in SDS-PAGE with a molecular weight of 40 kDa; K(m) and V(max) for isocitrate are 8.2 ± 0.28 and 525 ± 25 μM NADPH/mg/min, respectively, and for cofactor NADP 67.5 ± 2.82 μM and V(max) 50.5 ± 2.12 μM NADPH/mg/min.
authors.affiliation: Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati 517507, India.
authors.forename: U Venkateswara
authors.initials: UV
authors.lastname: Prasad
authors.forename: D
authors.initials: D
authors.lastname: Vasu
authors.forename: Y Nanda
authors.initials: YN
authors.lastname: Kumar
authors.forename: P Santhosh
authors.initials: PS
authors.lastname: Kumar
authors.forename: S
authors.initials: S
authors.lastname: Yeswanth
authors.forename: V
authors.initials: V
authors.lastname: Swarupa
authors.forename: B V
authors.initials: BV
authors.lastname: Phaneendra
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chaudhary
authors.forename: P V G K
authors.initials: PV
authors.lastname: Sarma
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D008970:Molecular Weight; D013211:Staphylococcus aureus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D007521:Isocitrate Dehydrogenase; C039355:isocitrate dehydrogenase (NADP+)