Genetically engineered synthetic miniaturized versions of Plasmodium falciparum UvrD helicase are catalytically active
Authors: Abulaish Ansari
Renu Tuteja
Mohammed Tarique
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Helicase; UvrD; Plasmodium falciparum; ATPase; DNA helicase
Affiliations: Malaria Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.

Abstract:  Helicases catalyze unwinding of double stranded nucleic acids in an energy-dependent manner. We have reported characterization of UvrD helicase from Plasmodium falciparum. We reported that the N-terminal and C-terminal fragments of PfUvrD contain characteristic ATPase and DNA helicase activities. Here we report the generation and characterization of a genetically engineered version of PfUvrD and its derivatives. This synthetic UvrD (sUD) contains all the conserved domains of PfUvrD but only the intervening linker sequences are shortened. sUD (‚à?45 kDa) and one of its smallest derivative sUDN1N2 (‚à?22 kDa) contain ATPase and DNA helicase activities. sUD and sUDN1N2 can utilize hydrolysis of all the NTPs and dNTPs, can also unwind blunt end duplex DNA substrate and unwind DNA duplex in 3 to 5 direction only. Some of the properties of sUD are similar to the PfUvrD helicase. Mutagenesis in the conserved motif Ia indicate that the mutants sUDM and sUDN1N2M lose all the enzyme activities, which further confirms that these activities are intrinsic to the synthesized proteins. These studies show that for helicase activity only the conserved domains are essentially required and intervening sequences have almost no role. These observations will aid in understanding the unwinding mechanism by a helicase. 

Retracted: Yes

PubPeer comments:
 June 2016 retraction found here: https: journals.plos.org plosone article?id=10.1371 journal.pone.0158859 From the Retraction Notice:  *The PLOS ONE editors retract this article following an investigation into concerns about the presentation of Figures 6 and 10.* *The PLOS ONE editors were alerted to concerns about Fig 6 and 10 in the article. Upon follow up with the authors and an evaluation of the raw data supplied, concerns about the figures remained and an institutional investigation was requested.* *The investigation conducted by the International Centre for Genetic Engineering and Biotechnology revealed that figures 6 and 10 show evidence of inappropriate manipulation: Fig 6 panels C and D are derived from the same gel; Fig 10 A, B and C are derived from the same gel. Additionally, the substrate structure as described in the text is missing from Fig 10.* *Consistent with the recommendation by the International Centre for Genetic Engineering and Biotechnology of the investigation panel, the PLOS ONE editors retract this publication. * Here are the concerns about the original Figures 6 and 10, as reported to the journal in April 2014. * Figure 6: Green boxes and arrows highlight that the two blots here appear to be identical if one of them is rotated 180 degrees. * Figure 10. Three of the blots here, marked in blue, lime green, and red, appear to all be the same. One of them is rotated 180 degrees.  ,