Cloning and characterization of the HpaII methylase gene

Card, C. O., Wilson, G. G., Weule, K., Hasapes, J., Kiss, A., Roberts, R. J. (March 1990) Cloning and characterization of the HpaII methylase gene. Nucleic Acids Res, 18 (6). pp. 1377-83. ISSN 0305-1048 (Print)0305-1048 (Linking)

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DOI: 10.1093/nar/18.6.1377


The HpaII restriction-modification system from Haemophilus parainfluenzae recognizes the DNA sequence CCGG. The gene for the HpaII methylase has been cloned into E. coli and its nucleotide sequence has been determined. The DNA of the clones is fully protected against cleavage by the HpaII restriction enzyme in vitro, indicating that the methylase gene is active in E. coli. The clones were isolated in an McrA-strain of E. coli; attempts to isolate them in an McrA+ strain were unsuccessful. The clones do not express detectable HpaII restriction endonuclease activity, suggesting that either the endonuclease gene is not expressed well in E. coli, or that it is not present in its entirety in any of the clones that we have isolated. The derived amino acid sequence of the HpaII methylase shows overall similarity to other cytosine methylases. It bears a particularly close resemblance to the sequences of the HhaI, BsuFI and MspI methylases. When compared with three other methylases that recognize CCGG, the variable region of the HpaII methylase, which is believed to be responsible for sequence specific recognition, shows some similarity to the corresponding regions of the BsuFI and MspI methylases, but is rather dissimilar to that of the SPR methylase.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Base Sequence *Cloning, Molecular DNA Modification Methylases/metabolism DNA, Bacterial/genetics/isolation & purification DNA-Cytosine Methylases/*genetics/metabolism Escherichia coli/genetics Gene Library *Genes, Bacterial Haemophilus/enzymology/*genetics Molecular Sequence Data Plasmids Recombinant Proteins/metabolism Restriction Mapping Sequence Homology, Nucleic Acid Substrate Specificity
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > restriction enzyme
CSHL Authors:
Communities: CSHL labs > Roberts lab
Depositing User: Matt Covey
Date: 25 March 1990
Date Deposited: 06 Apr 2016 15:04
Last Modified: 08 Nov 2017 16:55
PMCID: PMC330500
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