Heteroduplex DNA mismatch repair system of Streptococcus pneumoniae: cloning and expression of the hexA gene

Journal Article · Sat Jun 01 00:00:00 EDT 1985 · J. Bacteriol.; (United States)

OSTI ID:5091628

Balganesh, T S; Lacks, S A

Mutations affecting heteroduplex DNA mismatch repair in Streptococcus pneumoniae were localized in two genes, hexA and hexB, by fractionation of restriction fragments carrying mutant alleles. A fragment containing the hexA4 allele was cloned in the S. pneumoniae cloning system, and the hexA/sup +/ allele was introduced into the recombinant plasmid by chromosomal facilitation of plasmid transfer. Subcloning localized the functional hexA gene to a 3.5-kilobase segment of the cloned pneumococcal DNA. The product of this gene was shown in Bacillus subtilis minicells to be a polypeptide with an M/sub r/ of 86,000. Two mutant alleles of hexA showed partial expression of the repair system when present in multicopy plasmids. A model for mismatch repair, which depends on the interaction of two protein components to recognize the mismatched base pair and excise a segment of DNA between strand breaks surrounding the mismatch, is proposed.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 5091628
• Journal Information: J. Bacteriol.; (United States), Vol. 162:3
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
DNA
GENETIC RADIATION EFFECTS
STREPTOCOCCUS
DNA REPAIR
DNA-CLONING
EXTREME ULTRAVIOLET RADIATION
GENES
MUTANTS
POLYPEPTIDES
STRAND BREAKS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CLONING
ELECTROMAGNETIC RADIATION
GENETIC EFFECTS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PEPTIDES
PROTEINS
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
ULTRAVIOLET RADIATION
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