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PMID:15489438

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Citation

Tiemann, B, Depping, R, Gineikiene, E, Kaliniene, L, Nivinskas, R and Rüger, W (2004) ModA and ModB, two ADP-ribosyltransferases encoded by bacteriophage T4: catalytic properties and mutation analysis. J. Bacteriol. 186:7262-72

Abstract

Bacteriophage T4 encodes three ADP-ribosyltransferases, Alt, ModA, and ModB. These enzymes participate in the regulation of the T4 replication cycle by ADP-ribosylating a defined set of host proteins. In order to obtain a better understanding of the phage-host interactions and their consequences for regulating the T4 replication cycle, we studied cloning, overexpression, and characterization of purified ModA and ModB enzymes. Site-directed mutagenesis confirmed that amino acids, as deduced from secondary structure alignments, are indeed decisive for the activity of the enzymes, implying that the transfer reaction follows the Sn1-type reaction scheme proposed for this class of enzymes. In vitro transcription assays performed with Alt- and ModA-modified RNA polymerases demonstrated that the Alt-ribosylated polymerase enhances transcription from T4 early promoters on a T4 DNA template, whereas the transcriptional activity of ModA-modified polymerase, without the participation of T4-encoded auxiliary proteins for middle mode or late transcription, is reduced. The results presented here support the conclusion that ADP-ribosylation of RNA polymerase and of other host proteins allows initial phage-directed mRNA synthesis reactions to escape from host control. In contrast, subsequent modification of the other cellular target proteins limits transcription from phage early genes and participates in redirecting transcription to phage middle and late genes.

Links

PubMed PMC523198 Online version:10.1128/JB.186.21.7262-7272.2004

Keywords

ADP Ribose Transferases/chemistry; ADP Ribose Transferases/genetics; ADP Ribose Transferases/isolation & purification; ADP Ribose Transferases/metabolism; Amino Acid Sequence; Bacteriophage T4/enzymology; Bacteriophage T4/physiology; Inclusion Bodies/enzymology; Molecular Sequence Data; Mutagenesis, Site-Directed; Mutation; Protein Renaturation; Transcription, Genetic

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

BPT4:MODB

enables

GO:0003956: NAD(P)+-protein-arginine ADP-ribosyltransferase activity

ECO:0000315: mutant phenotype evidence used in manual assertion

F

Seeded From UniProt

complete

BPT4:MODA

GO:0070213: protein auto-ADP-ribosylation

ECO:0000314:

P

Fig 2 "Self-ADP-ribosylation of ModA and ModB was also observed in the reactions"

complete
CACAO 12071

BPT4:MODA

enables

GO:0003956: NAD(P)+-protein-arginine ADP-ribosyltransferase activity

ECO:0000315: mutant phenotype evidence used in manual assertion

F

Seeded From UniProt

complete

Notes

See also

References

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