The protein that binds to DNA base J in trypanosomatids has features of a thymidine hydroxylase.
Trypanosomatids contain an unusual DNA base J (beta-d-glucosylhydroxymethyluracil), which replaces a fraction of thymine in telomeric and other DNA repeats. To determine the function of base J, we have searched for enzymes that catalyze J biosynthesis. We present evidence that a protein that binds to J in DNA, the J-binding protein 1 (JBP1), may also catalyze the first step in J biosynthesis, the conversion of thymine in DNA into hydroxymethyluracil. We show that JBP1 belongs to the family of Fe(2+) and 2-oxoglutarate-dependent dioxygenases and that replacement of conserved residues putatively involved in Fe(2+) and 2-oxoglutarate-binding inactivates the ability of JBP1 to contribute to J synthesis without affecting its ability to bind to J-DNA. We propose that JBP1 is a thymidine hydroxylase responsible for the local amplification of J inserted by JBP2, another putative thymidine hydroxylase.
Yu
Zhong
Z
Division of Molecular Biology and Centre of Biomedical Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Genest
Paul-André
PA
ter Riet
Bas
B
Sweeney
Kate
K
DiPaolo
Courtney
C
Kieft
Rudo
R
Christodoulou
Evangelos
E
Perrakis
Anastassis
A
Simmons
Jana M
JM
Hausinger
Robert P
RP
van Luenen
Henri G A M
HG
Rigden
Daniel J
DJ
Sabatini
Robert
R
Borst
Piet
P
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D049308:Dioxygenases / Q000145:classification; D005960:Glucosides / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D007891:Leishmania / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D014498:Uracil / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism
D004268:DNA-Binding Proteins; D005960:Glucosides; C402790:J-specific DNA-binding protein, protozoa; D015800:Protozoan Proteins; C084880:5-((glucopyranosyloxy)methyl)uracil; D014498:Uracil; D006899:Mixed Function Oxygenases; D049308:Dioxygenases; C023162:thymidine,2-oxoglutarate dioxygenase