title: ADP-ribosylation of guanosine by SCO5461 protein secreted from Streptomyces coelicolor.
abstract: The Streptomyces coelicolor A3(2) genome encodes a possible secretion protein, SCO5461, that shares a 30% homology with the activity domains of two toxic ADP-ribosyltransferases, pierisins and mosquitocidal toxin. We found ADP-ribosylating activity for the SCO5461 protein product through its co-incubation with guanosine and NAD(+), which resulted in the formation of N(2)-(ADP-ribos-1-yl)-guanosine ((ar2)Guo), with a K(m) value of 110 μM. SCO5461 was further found to ADP-ribosylate deoxyguanosine, GMP, dGMP, GTP, dGTP, and cyclic GMP with k(cat) values of 150-370 s(-1). Oligo(dG), oligo(G), and yeast tRNA were also ADP-ribosylated by this protein, although with much lower k(cat) values of 0.2 s(-1) or less. SCO5461 showed maximum ADP-ribosylation activity towards guanosine at 30 °C, and maintained 20% of these maximum activity levels even at 0 °C. This is the first report of the ADP-ribosylation of guanosine and guanine mononucleotides among the family members of various ADP-ribosylating enzymes. We additionally observed secretion of the putative gene product, SCO5461, in liquid cultures of S. coelicolor. We thus designated the SCO5461 protein product as S. coelicolor ADP-ribosylating protein, ScARP. Our current results could offer new insights into not only the ADP-ribosylation of small molecules but also signal transduction events via enzymatic nucleoside modification by toxin-related enzymes.
authors.affiliation: Division of Cancer Development System, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan. tnakano@pp.iij4u.or.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakano
authors.forename: Yuko
authors.initials: Y
authors.lastname: Matsushima-Hibiya
authors.forename: Masafumi
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Azusa
authors.initials: A
authors.lastname: Takahashi-Nakaguchi
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fukuda
authors.forename: Masaya
authors.initials: M
authors.lastname: Ono
authors.forename: Takeji
authors.initials: T
authors.lastname: Takamura-Enya
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Kinashi
authors.forename: Yukari
authors.initials: Y
authors.lastname: Totsuka
mesh_terms: D036002:ADP Ribose Transferases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D006151:Guanosine / Q000378:metabolism*; D008969:Molecular Sequence Data; D015398:Signal Transduction; D048372:Streptomyces coelicolor / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D018076:DNA, Complementary; D006151:Guanosine; D036002:ADP Ribose Transferases