The catalytic core of Leishmania donovani RECQ helicase unwinds a wide spectrum of DNA substrates and is stimulated by replication protein A

Shikha, K and Sriram Bharath, G and Mukhopadhyay, S and Chakraborty, M and Ghosh, S and Khatun, S and De, D and Gupta, AN and Ganguly, A (2021) The catalytic core of Leishmania donovani RECQ helicase unwinds a wide spectrum of DNA substrates and is stimulated by replication protein A. In: FEBS Journal .

	PDF feb_jou_2021.pdf - Published Version Restricted to Registered users only Download (6MB) | Request a copy
	Archive (ZIP) febs16153-sup-0001-supinfo.zip - Published Supplemental Material Restricted to Registered users only Download (1MB) | Request a copy

Abstract

RecQ helicases are superfamily 2 (SF2) DNA helicases that unwind a wide spectrum of complex DNA structures in a 3� to 5� direction and are involved in maintaining genome stability. RecQ helicases from protozoan parasites have gained significant interest in recent times because of their involvement in cellular DNA repair pathways, making them important targets for drug development. In this study, we report biophysical and biochemical characterization of the catalytic core of a RecQ helicase from hemoflagellate protozoan parasite Leishmania donovani. Among the two putative RecQ helicases identified in L. donovani, we cloned, overexpressed and purified the catalytic core of LdRECQb. The catalytic core was found to be very efficient in unwinding a wide variety of DNA substrates like forked duplex, 3� tailed duplex and Holliday junction DNA. Interestingly, the helicase core also unwound blunt duplex with slightly less efficiency. The enzyme exhibited high level of DNA-stimulated ATPase activity with preferential stimulation by forked duplex, Holliday junction and 3� tailed duplex. Walker A motif lysine mutation severely affected the ATPase activity and significantly affected unwinding activity. Like many other RecQ helicases, L. donovani RECQb also possesses strand annealing activity. Unwinding of longer DNA substrates by LdRECQb catalytic core was found to be stimulated in the presence of replication protein A (LdRPA-1) from L. donovani. Detailed biochemical characterization and comparison of kinetic parameters indicate that L. donovani RECQb shares considerable functional similarity with human Bloom syndrome helicase. © 2021 Federation of European Biochemical Societies.

Item Type:	Journal Article
Publication:	FEBS Journal
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to John Wiley and Sons Inc
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	21 Nov 2021 16:27
Last Modified:	21 Nov 2021 16:27
URI:	http://eprints.iisc.ac.in/id/eprint/69930

Actions (login required)

View Item