Journal of Microbiology

An Analysis of the Arm-type Site Binding Domain of Bacteriophage γ Integrase: Cho , Eun Hee; J. Microbiol. 1995;33(2):165-170.

Abstract: The 356 amino acid long lambda integrase protein of bacteriophage λ constains two autonomous DNA binding domains with distinct sequence specificities. The amino terminal domain of integrase is implicated to bind to the arm-type sequences and the carboxyl domain interacts with the coretype sequencess. As a first step to understand the molecular mechanism of the integrase-DNA interaction at the arm-type site, the int(am)94 gene carrying an amber mutation at the 94th codon of the int was cloned under the control of the P_tac promoter and the lacI^q gene. The Int(am)94 mutant protein of amino terminal 93 amino acid residues can be produced at high level from a suppressor free strain harboring the plasmid pInt(am)94. The arm-type binding activity of Int(am)94 were measured in vivo and in vitro. A comparison of the arm-type binding properties of the wild-type integrase and the truncated Int(am)94 mutant indicated that the truncated fragment containing 93 amino acid residues carry all the determinants for DNA binding at the arm-type sites.

Characterization and Identification of the Bacteriophage P4 Mutant Suppressin sir Mutations of Bacteriophage P2: Kim, Kyoung Jin , Sunshine, Melvin G. , Six, Erich W.; J. Microbiol. 1998;36(4):262-265.

Abstract: Bacteriophage P4 ost1 was isolated as a suppressor mutant of P2 sir3 and identified by restriction enzyme site analysis. The mutant DNA turned out to be an imperfect P4 trimer containing deletions. It was suggested that the deletion resulted from int-mediated site-specific recombination. CsCl equilibrium density gradient experiment confirmed the genome size of P4 ostl.

Secondary Structure Analysis of Amino Terminal Domain in Phage Lambda Integrase: Yu, Jeong A , Nam, Chan Eun , Cho, Eun Hee; J. Microbiol. 1998;36(4):266-272.

Abstract: The amino-terminal domain of bacteriophage λ integrase recognizes specific DNA sequences called arm-type sites. To study the structural and functional relationships of the integras armtype DNA binding domains were confirmed by gel mobility-shift assay. The polypeptides were subjected to circular dichroism spectroscopy to estimate the amount of secondary structures they contain Based upon analyses of circular dichroism spectra and comparison with predicted secondary structural compositions, it was estimated that the amino terminal domain of integrase in an aqueous solution was composed of a little α-helical region. The helical content increased with an increasing amount of ethanol, an α-helix inducer. This indicates that its conformation can be changed to a form with higher content of α-helical structure under a certain condition.

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