ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
The actinomycete Amycolatopsis methanolica contains a 13.3 kb plasmid (pMEA300), capable of enhancing the spontaneous mutation frequency of its host. Depending on the growth medium pMEA300 is not only maintained as an integrated element but can additionally be present as a multicopy, autonomously replicating plasmid. The minimal replicon of pMEA300 was identified. Two unlinked DNA fragments of 2.6 kb and 0.8 kb were required for pMEA300 maintenance. Sequence analysis of the 2.6 kb fragment revealed at least two open reading frames, orfA and orfB, encoding putative proteins of 170 amino acids (18 373 Da) and 416 amino acids (45 260 Da), respectively. No clear similarities were found between the deduced amino acid sequences of the putative orfA and orfB products of pMEA300 and replication proteins identified for various Streptomyces plasmids. The pMEA300 proteins of A. methanolica thus may represent unfamiliar types. The 0.8 kb fragment contained a single complete open reading frame (korA), encoding a protein of 118 amino acids (12 917 Da). The putative KorA protein of pMEA300 shows sequence similarity with various other Streptomyces plasmid-encoded Kor proteins which may belong to the GntR family of transcriptional repressor proteins. The data provide preliminary evidence for the possible involvement of a kil—kor system in autonomous replication of pMEA300.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2958.1995.mmi_18010021.x
Permalink