Identification, molecular cloning, and sequence analysis of a deoxyribose aldolase in Streptococcus mutans GS-5.
Bacterial fitness in the environment, where nutrients are limited and competition is intense, plays a central role in survival and virulence of the organisms. Deoxyribose aldolase, found in several species of bacteria, is known to be involved in the catabolism of deoxynucleosides arising from dead cells, thereby giving a selective advantage to the microorganisms with a capability to consume DNA as an alternative carbon and energy source. A gene encoding a deoxyribose aldolase gene ( deoC) was identified in the cariogenic Streptococcus mutans strain GS-5 by comparative sequence analysis and gene cloning. The gene encodes a protein of 220 amino acids, having a predicted molecular weight of 23.3 kDa with a p I of 5.44. The gene was cloned into the expression vector pFLAG-1, and the biological function of the gene product was analyzed by a complementation assay with a deoC(-) Escherichia coli mutant SPhi063. Transformation of the E. coli SPhi063 with the plasmid construct allowed this organism to grow on glucose minimal medium supplemented with 2 mM deoxyadenosine or deoxythymidine. These results showed activity of deoxyribose aldolase, confirming the identity of the gene. Utilization of exogenous deoxynucleotides as a carbon and energy source may confer a survival and growth advantage to S. mutans over other bacteria in dental plaque, suggesting that deoxyribose aldolase may be a contributing factor to virulence.
Han
Thomas K
TK
Department of Biology SCA110, College of Arts and Sciences, University of South Florida, Tampa, FL 33620-5150, USA.
Zhu
Zhiwen
Z
Dao
My Lien
ML
D000446:Aldehyde-Lyases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D003839:Deoxyadenosines / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017353:Gene Deletion; D023061:Gene Order; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D005947:Glucose / Q000378:metabolism; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020161:Physical Chromosome Mapping; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013295:Streptococcus mutans / Q000201:enzymology* / Q000235:genetics*; D013936:Thymidine / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000502:physiology
D003470:Culture Media; D004269:DNA, Bacterial; D003839:Deoxyadenosines; D037521:Virulence Factors; D000446:Aldehyde-Lyases; C020019:deoxyribose-phosphate aldolase; D005947:Glucose; D013936:Thymidine