Previous Article | Next Article ![]()
J. Bacteriol., 11 1995, 6499-6505, Vol 177, No. 22
JW Vrijbloed, NM van der Put and L Dijkhuizen
Amycolatopsis methanolica contains a 13.3-kb plasmid (pMEA300) that is
present either as an integrated element or as an autonomously replicating
plasmid. Conjugational transfer of pMEA300 results in pock formation, zones
of growth inhibition that become apparent when plasmid- carrying donor
cells develop in a confluent lawn of plasmid-lacking recipient cells. A
6.2-kb pMEA300 DNA region specifying the functions of conjugation and pock
formation was sequenced, revealing 10 open reading frames. This is the
first sequence of the transfer region of a plasmid from a nonstreptomycete
actinomycete. No clear similarities were found between the deduced
sequences of the 10 putative Tra proteins of pMEA300 and those of
Streptomyces plasmids. All Tra proteins of pMEA300 thus may represent
unfamiliar types. A detailed mutational analysis showed that at least four
individual proteins, TraG (9,488 Da), TraH (12,586 Da), TraI (40,468 Da),
and TraJ (81,109 Da), are required for efficient transfer of pMEA300. Their
disruption resulted in a clear reduction in the conjugational transfer
frequencies, ranging from (5.2 x 10(1))-fold (TraG) to (2.3 x 10(6))- fold
(TraJ), and in reduced pock sizes. At least two putative proteins, TraA
(10,698 Da) and TraB (31,442 Da), were shown to be responsible for pock
formation specifically. Specific binding of the pMEA300-encoded KorA
protein to the traA-korA intragenic region was observed.
Copyright © 1995, American Society for Microbiology
Identification and functional analysis of the transfer region of plasmid pMEA300 of the methylotrophic actinomycete Amycolatopsis methanolica
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Haren, The Netherlands.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |