Evolution of RNA-binding specificity in T4 DNA polymerase

Chien Chia Wang, Andrey Pavlov, Jim D. Karam

研究成果: 雜誌貢獻期刊論文同行評審

18 引文 斯高帕斯(Scopus)

摘要

DNA polymerase of phage T4 (T4 gp43), an essential component of the T4 DNA replicase, is a multifunctional single-chained (898-amino acid) protein that catalyzes the highly accurate synthesis of DNA in phage replication. The enzyme functions both as a DNA-binding replication protein and as a sequence- specific RNA-binding autogenous translational repressor. We have utilized a phylogenetic approach to study the relationships between the two nucleic acid-binding functions of the protein. We found that autogenous translational control of gp43 biosynthesis has been conserved in phage RB69, a distant relative of T4, although we also found that the RB69 system differs from its T4 counterpart in two regards: (a) nucleotide sequence and predicted secondary structure of the RNA target (translational operator), and (b) RNA specificity of the protein. T4 gp43 is specific to the RNA operator sequence of the T4 genome whereas RB69 gp43 can bind and repress operator RNA from both phages equally well. In studies with T4-RB69 gp43 chimeras, we mapped T4 gp43 RNA-binding specificity to a protein segment that also harbors important determinants for DNA binding and the polymerase catalytic function. Our results suggest that RNA functions as a regulator of both the dosage and activity of this DNA replication enzyme.

原文???core.languages.en_GB???
頁(從 - 到)17703-17710
頁數8
期刊Journal of Biological Chemistry
272
發行號28
DOIs
出版狀態已出版 - 1997

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