Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Streptomyces coelicolor A3(2) possesses two plasmids (SCP1 and SCP2) that act as sex factors. The plasmid deoxyribonucleic acid isolated from S. coelicolor A3(2) SCP1- strains A617 and A585 had the same molecular weight and endonuclease cleavage pattern as the SCP2 plasmid. The plasmidless strain S18 SCP2- was isolated from the A617 X A585 cross. SCP2 plasmid-containing strains acted as donors of chromosomal markers, whereas the plasmidless strain acted as recipient. The transfer of SCP2+ donor strain markers into the SCP2- recipient occurred at high frequencies (approximately 75%), was unidirectional, was initiated from a fixed region of the chromosome, and had the SCP2 fertility factor transferred first. The introduction of the SCP2 plasmid into a recipient strain greatly reduced the recombination frequency. These fertility properties differed from those previously reported, thereby suggesting that the SCP2 plasmid examined in this investigation may be an additional variant to those described in the literature. The SCP2 plasmid also regulated production of three antibacterial substances and conveyed resistance for S. coelicolor A3(2) strains against growth inhibition by one of them.
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PMID:Fertility properties and regulation of antimicrobial substance production by plasmid SCP2 of Streptomyces coelicolor. 50 May 59

When strains of Streptomyces coelicolor A3(2) lacking the previously identified autonomous plasmids SCP1 and SCP2 are crossed with Streptomyces lividans 66, some of the S. lividans progeny are able to elicit zones of growth inhibition (lethal zygosis), previously associated with the transfer of conjugative Streptomyces plasmids, when grown in contact with S. lividans 66. Some such progeny yield covalently closed circular (CCC) plasmid DNA, the size and restriction endonuclease cleavage pattern of which is constant for a particular isolate, but varies among isolates. These plasmids, which have been named SLP1.1, SLP1.2, etc., all confer resistance to lethal zygosis elicited by the others. Genetic and molecular characterization of the plasmids reveals that they are derived from the strA region of the chromosome of S. coelicolor. It is proposed that, before or during mating with S. lividans, the SLP1 sequences are excised from the chromosome, bringing varying regions of the surrounding chromosome with them, and can circularize to yield the SLP1 family of plasmids. Autonomous SLP1 plasmids can also be generate by cleaving total DNA of S. coelicolor with certain restriction enzymes, ligating it, and transforming the DNA into S. lividans. The autonomous SLP1 plasmids exist within S. lividans in a few copies per chromosome, and act as fertility factors. They provide suitable vectors for DNA cloning since the segments of chromosomal DNA carried by the larger members of the family are dispensable.
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PMID:Excision of chromosomal DNA sequences from Streptomyces coelicolor forms a novel family of plasmids detectable in Streptomyces lividans. 694 98