A novel active DNA topoisomerase I in Leishmania donovani.
A common feature shared by type I DNA topoisomerases is the presence of a "serine, lysine, X, X, tyrosine" motif as conventional enzyme active site. Preliminary data have shown that Leishmania donovani DNA topoisomerase I gene (LdTOP1A) lacked this conserved motif, giving rise to different theories about the reconstitution of an active DNA topoisomerase I in this parasite. We, herein, describe the molecular cloning of a new DNA topoisomerase I gene from L. donovani (LdTOP1B) containing the highly conserved serine, lysine, X, X, tyrosine motif. DNA topoisomerase I activity was detected only when both genes (LdTOP1A and LdTOP1B) were co-expressed in a yeast expression system, suggesting the existence of a dimeric DNA topoisomerase I in Leishmania parasites.
Villa
Héctor
H
Departamento de Farmacologia y Toxicologia (INTOXCAL), Universidad de León, Campus de Vegazana sn, 24071 León, Spain.
Otero Marcos
Ana R
AR
Reguera
Rosa M
RM
Balaña-Fouce
Rafael
R
García-Estrada
Carlos
C
Pérez-Pertejo
Yolanda
Y
Tekwani
Babu L
BL
Myler
Peter J
PJ
Stuart
Kenneth D
KD
Bjornsti
Mary-Ann
MA
Ordóñez
David
D
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017125:Genes, Protozoan; D006801:Humans; D007893:Leishmania donovani / Q000201:enzymology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D004264:DNA Topoisomerases, Type I