[The Sse9I restriction-modification system: organization of genes and comparative analysis of proteins structures].

A nucleotide sequence was established for the full-length Sporosarcina species 9D operon coding for enzymes of type II restriction-modification system Sse9I. These enzymes recognize the tetranucleotide DNA sequence 5'-AATT-3'. The operon was shown to consist of three genes that are situated with the order: sse9IC-sse9IR-sse9IM and are transcribed in the same direction.

BstF5I, an unusual isoschizomer of FokI.

BstF5I, a new restriction endonuclease (ENase) from Bacillus stearothermophilus F5, has been discovered. This enzyme recognizes 5'-GGATG-3' and cleaves DNA, generating a 2-base 3'extension: 5'-GGATG NN[symbol: see text]-3' 3'-CCTAC[symbol: see text]NN-5' BstF5I is an isoschizomer of FokI and seems to be evolutionarily close to other nonpalindromic-recognizing ENases from thermophilic bacilli.

CciNI, an isoschizomer of NotI from Curtobacterium citreum recognizes 5'-GC decreases GGCCGC-3'.

CciNI, an isoschizomer of NotI, has been isolated from Curtobacterium citreum. The enzyme cleaves within the recognition sequence 5'-GC decreases GGCCGC-3' as indicated by the arrow.

[Effect of poly(dA).poly(dT) sequence inserted into EcoR1 site of pBr322 plasmid on the expression of tet and bla genes].

The 99 base pair poly(dA).poly(dT) stretch was inserted into EcoRI site of pBR plasmid. The effect of this insertion on tet-gene expression from P2 promoter, and bla-gene expression from P1 and P3 promoters was studied.

[Effectiveness of the promoter Ptac' in vitro and in mini-cells].

The efficiency of hybrid promotor Ptac', comprising a synthetic trp-promoter and lacUV5 "-10" sequence, was studied. By means of electrophoresis and hybridization of RNA-products obtained in vitro and in minicells, with promotor-containing plasmids; the hybrid promotor was found to be 6 times and 3-4 times as efficient as trp and lacUV5 promoters, respectively.