UMMS Affiliation

Department of Pharmacology and Molecular Toxicology

Date

7-1-1996

Document Type

Article

Subjects

*Adenosine Triphosphatases; Bacterial Proteins; DNA Mutational Analysis; DNA, Bacterial; Escherichia coli; *Escherichia coli Proteins; Gene Dosage; Genes, Bacterial; Genetic Complementation Test; Mutagenesis; Repetitive Sequences, Nucleic Acid; Sequence Analysis, DNA

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

The mutL gene product is part of the dam-directed mismatch repair system of Escherichia coli but has no known enzymatic function. It forms a complex on heteroduplex DNA with the mismatch recognition MutS protein and with MutH, which has latent endonuclease activity. An N-terminal hexahistidine-tagged MutL was constructed which was active in vivo. As a first stop to determine the functional domains of MutL, we have isolated 72 hydroxylamine-induced plasmid-borne mutations which impart a dominant-negative phenotype to the wild-type strain for increased spontaneous mutagenesis. None of the mutations complement a mutL deletion mutant, indicating that the mutant proteins by themselves are inactive. All the dominant mutations but one could be complemented by the wild-type mutL at about the same gene dosage. DNA sequencing indicated that the mutations affected 22 amino acid residues located between positions 16 and 549 of the 615 amino acid protein. In the N-terminal half of the protein, 12 out of 15 amino acid replacements occur at positions conserved in various eukaryotic MutL homologs. All but one of the sequence changes affecting the C-terminal end of the protein are nonsense mutations.

Rights and Permissions

Citation: Nucleic Acids Res. 1996 Jul 1;24(13):2498-504.

Related Resources

Link to Article in PubMed

Journal Title

Nucleic acids research

PubMed ID

8692687

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.