Abstract: It is intended to obtain DNA ligase improved in binding ability and reactivity with DNA, particularly thermostable DNA ligase improved in binding ability and reactivity with DNA. The present invention provides a DNA ligase mutant improved in binding ability and reactivity with DNA, which is obtained by partially or completely deleting a C-terminal helix portion of DNA ligase. Particularly, the mutant is derived from a thermostable bacterium.

Abstract: There is provided a method for the detection of a base sequence of interest when amount of a sample DNA or RNA is little and plural base sequences of interest to be detected are present in the sample DNA or RNA. The Problem is solved by a method for the detection of an base sequence of interest in a sample DNA or RNA comprising the steps of (1) contacting a sample DNA or RNA to a probe DNAs or RNAs in an aqueous solution to form a hybridization complex; (2) isolating the hybridization complex; (3) dissociating the complex to recover the probe DNAs or RNAs; and (4) identifying the said probe DNAs or RNAs to detect an base sequence of interest in the sample DNA or RNA.

Abstract: The object of the invention is to provide proteins that have both DNA primase activity and DNA polymerase activity. This subject is solved by a protein (p41) that has an amino acid sequence shown in SEQ ID NO: 1. This is for the first time that proteins that have both DNA primase activity and DNA polymerase activity were found. A protein (p46) that has amino acid sequence shown in SEQ ID NO: 2 forms a complex with p41, and enforces DNA synthesis activity that is independent and/or dependent from primer of p41.

Abstract: The present invention relates to a DNA polymerase possesses the properties of 1) exhibiting higher polymerase activity when assayed by using as a substrate a complex resulting from primer annealing to a single stranded template DNA, as compared to the case where an activated DNA is used as a substrate; 2) possessing a 3′→5′ exonuclease activity; 3) being capable of amplifying a DNA fragment of about 20 kbp, in the case where polymerase chain reaction (PCR) is carried out using &lgr;-DNA as a template. It also relates to a DNA polymerase-constituting protein; a DNA containing the base sequence encoding thereof; and a method for producing the DNA polymerase. The present invention provides a novel DNA polymerase possessing both a high primer extensibility and a 3′→5′ exonuclease activity.

Abstract: The present invention provides a thermostable protein having deoxyribonuclease activity that specifically acts on and cleaves a Holliday structured DNA, which is an intermediate structure in the DNA recombination process, to resolve it into two sets of double-stranded DNAs.

Abstract: This invention provides A method for preparing mutant genes, which comprises the steps of constructing a recombinant plasmid DNA by inserting a gene fragment into a plasmid DNA having a unidirectional origin, introducing the recombinant plasmid DNA into host cell lacking DNA error-correcting function to transform the host cell, and culturing the transformant cell in a condition that any mutations of the inserted gene is detectable. According to the present invention, diverse mutant genes can be prepared in a short period of time.

Abstract: An isolated BalI restriction enzyme gene and an BalI isolated modification enzyme gene are disclosed. A process for preparing a large amount of BalI restriction enzyme which comprises culturing a transformant containing said genes and collecting BalI restriction enzyme from the culture broth is also disclosed.

Abstract: The present invention is directed to a method for cloning a gene for Pol I type DNA polymerase comprising;(a) amplifying target DNA with PCR using primers specific to said genes;(b) cloning a gene for Pol I type DNA polymerase with a probe selected from amplified DNA. And this invention is directed to a novel isolated gene coding for Pol I type DNA polymerase cloned in the plasmid.

Abstract: A restriction endonuclease which recognizes the nucleotide sequence of the following Chemical formula 1 in double stranded DNA and strictly cleaves the nucleotide sequence at the sites marked by arrows. ##STR1## The endonuclease may be made cultivating a strain of the genus Streptomyces such as Streptomyces sp. YH 8647 (FERM BP-5022) capable of producing it.

Abstract: A new restriction endonuclease capable of recognizing the nucleotide sequence of the following formula 1 in double stranded DNA. ##STR1## and specifically cleaving it is disclosed. The endonuclease may be made cultivating a strain of the genus Streptomyces (FERM BP-4836) capable of producing it.

Abstract: The present invention is directed to a method for cloning a gene for Pol I type DNA polymerase comprising;(a) amplifying target DNA with PCR using primers specific to said genes;(b) cloning a gene for Pol I type DNA polymerase with a probe selected from amplified DNA. And this invention is directed to a novel isolated gene coding for Pol I type DNA polymerase cloned in the plasmid.